Ernesto Casillas, BS

Maternal postpartum depression occurs in 5% to 25% of all mothers, and up to 40% to 60% in high‐risk populations such as low‐income women.[1, 2, 3, 4] Children of affected mothers suffer negative health consequences such as decreased physical growth, poor maternalchild bond, problem behavior, and child abuse.[5, 6, 7] Timely recognition of symptoms and treatment may improve child outcomes.[8] Published guidelines recommend pediatricians screen for postpartum depression at infant 1‐, 2‐, 4‐, and 6‐month outpatient visits.[9] There are no current guidelines for or studies of screening in general inpatient settings, although emergency rooms[10] and neonatal intensive care units (NICUs)[11] have been examined. Pediatric hospitalization may offer an additional opportunity for expanding screening and intervention.

Augmenting outpatient screening practices with additional inpatient screening would have several benefits. Infant health problems have been associated with postpartum depression, and therefore mothers in the hospital may be at higher risk.[12] Inpatient screening would also improve access to mothers not screened as outpatients. Missed screening could occur due to physician discomfort with screening, time constraints during busy office visits, or noncompliance with recommended visit schedules.[13, 14, 15, 16] Finally, inpatient providers would benefit from understanding the psychosocial milieu of children now under their care. Recent studies note hospital discharges may be improved and readmissions reduced by assessing socioeconomic risk factors during hospitalization.[17] The evidence‐based Peds Effective Discharge: Better Handoff to Home through Safer Transitions Better Outcomes by Optimizing Safe Transitions (Pedi‐BOOST) toolkit specifically recommends an assessment of parental psychiatric issues.[18] Postpartum depression strongly correlates with impaired maternalchild bonding,[19] which in turn negatively affects mothers' engagement with healthcare providers.[20] This could impact patient education and recommendations provided during hospitalization.

Therefore, we sought to perform postpartum depression screening during infant hospitalizations. Our primary goal was to determine rate of postpartum depression in our population and proportion of women previously unscreened who could be captured by inpatient screening. We additionally aimed to determine the proportion of women with poor maternalinfant bond. Our next goal was to identify maternal or infant factors associated with positive postpartum depression screening. Finally, we performed follow‐up calls to determine if in‐hospital interventions resulted in formal postpartum depression diagnosis, use of recommended referrals, improved maternalchild bond, and decreased symptoms of depression over time.

METHODS

RESULTS

Out of 366 motherinfant pairs, 56 (15%) refused, and 310 (85%) mothers were fully enrolled (Figure 1A). Mothers had an average age of 28.17 years, were 68.3% Hispanic/Latina by self‐report, and 45.2% were married. Infants were an average of 4.24 months old, 81.9% were born term (>37 weeks), and 64.8% were previously healthy (Table 1).

Figure 1

Eighty‐seven (28%) mothers were EPDS+; 223 (72%) were EPDS. Only 42 mothers reported previous postpartum depression screening since the birth of their most recent child. However, 30 infants were <1 month in age, thus outside recommended screening range. Eliminating these infants revealed a 14.6% rate of appropriate prior screening. Higher EPDS scores were associated with higher (worse) MIB scores by linear regression ( = 0.11, P < 0.001). The vast majority (77%) of mothers scored a 0 or 1 on the MIB scale, indicating good bonding; further statistical comparison using the MIB scale as a secondary outcome was therefore inappropriate.

On bivariate logistic regression, Hispanic/Latina women were less likely to be EPDS+ (odds ratio [OR]: 0.43; 95% CI: 0.23‐0.84) compared to white/Caucasian women. Mothers who identified Spanish as their primary language and took the Spanish EPDS had lower odds of a positive screen (OR: 0.47; 95% CI: 0.25‐0.88). The racial differences did not persist on multivariate analysis (OR: 0.64; 95% CI: 0.30‐1.38) (Table 2). Maternal characteristics identified as potential risk factors for positive screens were poor social support (OR: 3.58; 95% CI: 1.95‐6.59) and history of a prior psychiatric diagnosis (OR: 5.07; 95% CI: 2.65‐9.72). There were no differences in age, number of children or people living in the home, relationship status, or breastfeeding rates by EPDS score.

Infant characteristics were next examined. Children of EPDS+ and EPDS mothers were similar in age, number of prior hospital admissions, gestational age at birth, and overall use of medical equipment (Table 2). To examine the effect of illness leading to hospitalization on EPDS+ risk, discharge diagnoses were collected and grouped into categories. Infants of EPDS+ mothers were more likely hospitalized for neurologic illness (P = 0.008) (see Supporting Table 1 in the online version of this article), but otherwise similar.

We next compared differences in long‐term infant comorbidities. The rate of having any comorbidity was similar between children of EPDS+ and EPDS mothers (39.1% vs 33.6%; P = 0.551). However, children of EPDS+ mothers were more likely to have mental retardation, hydrocephalus, or require ventriculoperitoneal shunt (VPS); however, the overall number of infants with each comorbidity was low. A neurodevelopmental comorbidity variable was created combining mental retardation, cerebral palsy, epilepsy, hydrocephalus, craniosynostosis, and VPS, resulting in 22 (7.1%) unique infants with 1 or more of these conditions. Having an infant with a neurodevelopmental comorbidity was a risk factor for positive postpartum depression screen (OR: 3.41; 95% CI: 1.41‐8.21). This continued to be significant (OR: 2.78; 95% CI: 1.03‐7.52) (Table 2) when controlling for maternal race/ethnicity, psychiatric history, and social support in multivariate logistic regression.

To determine if women screened followed through with recommendations, participants were called 3 and 6 months postenrollment. We attempted to call all women and successfully reached 120; 19 (16%) refused the call. One hundred one of the original 310 enrolled (33%) completed at least 1 follow‐up call; 47 at 3 months, 40 at 6 months, and only 14 (14%) responded at both time points. Due to this response rate, the first call at either 3 or 6 months was used as a single follow‐up time point for statistical analysis. A slightly higher proportion of EPDS‐ mothers (80/223, 36%) completed calls compared to EPDS+ mothers (21/87, 24%; P = 0.047).

Of 21 mothers initially EPDS+ who completed a follow‐up call, 10 (48%) later screened negative. Seven of these 10 (70%) reported discussing postpartum depression with their physician or using provided referral resources in the interim; 1 woman both spoke to a doctor and used a referral resource. One additional woman used resources, but repeat EPDS was still positive (Table 3). Reasons cited for not seeking evaluation included too busy (n = 4) and lost paperwork (n = 1), or no reason was given (n = 2). Mothers utilizing appropriate follow‐up had reduction in scores compared to those not (F(1,19) = 5.743, P = 0.027), although all scores decreased over time (F(1,19) = 11.54, P = 0.0030) (Figure 1B).

Of 80 women initially EPDS, most stayed negative (73/80, 91%), but 7 (9%) became EPDS+. These mothers received education and referral information over the phone, but none completed a subsequent call. Infants of mothers initially EPDS had a higher frequency of hospitalization postenrollment compared to EPDS+ mothers (P = 0.021) (Table 3). Two (33%) mothers who converted from EPDS to EPDS+ had infants readmitted in the follow‐up period.

DISCUSSION

This study demonstrated almost a third of mothers of hospitalized infants are at risk for postpartum depression and most had not been previously screened. Stress due to hospitalization did not seem to falsely elevate EPDS scores; the proportion of EPDS+ mothers matched our prestudy prediction (28% vs 27.9%). Follow‐up calls indicated that EPDS+ mothers not pursuing further evaluation tended to remain EPDS+. Higher (worse) MIB score was strongly correlated to increased EPDS score as expected, supporting screening accuracy. Our results suggest that postpartum depression screening in hospital settings can be used to complement outpatient practice and capture mothers who would otherwise be missed.

Although we were able to screen, it is difficult to know whether this correctly identified mothers with postpartum depression. Only 2 mothers reported subsequent official diagnosis of postpartum depression, and 1 of these was EPDS originally. This reflects weakness of our survey‐based design; we only know if the mother self‐reported a formal diagnosis of postpartum depression, because we do not have access to their medical charts. We also had higher than expected loss to follow up (67%), leaving 66 initially EPDS+ mothers with unknown eventual diagnoses. The EPDS has been validated in multiple populations and has a positive predictive value ranging from 23% to 93%.[23] Therefore, somewhere between 20 and 80 women in our study should meet diagnostic criteria for postpartum depression. A limitation of children's hospital‐based screening with the EPDS is lack of adult‐trained psychiatrists who could immediately follow screening with diagnosis. Such integration may already be possible at community or hospital‐within‐a‐hospital models, and could be trialed at children's hospitals. Regardless, participation in the study seemed to increase mothers' awareness of postpartum depression. Prior to enrollment, only 14.6% of subjects reported discussing postpartum depression with a physician, although recall bias likely contributed to some mothers not remembering a screen. Promisingly, on follow‐up, 37% of called participants reported they discussed postpartum depression with a doctor following their child's hospital discharge.

Our study identified low social support and history of past psychiatric diagnosis as maternal risk factors for EPDS+ screens, which is consistent with previous reports.[29] There was a slight increase in subsequent infant hospitalizations in the EPDS group, which is contrary to reports stating that increased healthcare utilization is associated with postpartum depression.[30] However, most studies have shown an increase in only acute or emergency room care visits[30, 31] and no association between maternal depression and infant hospitalization.[30, 32] In our study, the median number of hospitalizations for both groups was 0, indicating overall low utilization. Because 2 of the mothers who converted from EPDS to EPDS+ had children readmitted, this underscores the benefit of reassessment at each medical encounter. A large proportion of mothers (36.5%) reported that the infant had been previously hospitalized, adding another potential missed screening opportunity. Our study supports others advocating repeated screenings and suggests mothers should be screened at any medical encounter that occurs in the first postpartum year.

We identified neurodevelopmental illness as the major infant characteristic associated with postpartum depression risk. Conversely, Garfield et al. did not find correlation between poorer Neurobiologic Risk Score and increased maternal depression risk in a NICU setting.[11] Perhaps our population of older and mainly full‐term infants makes consequences of neurologic insult more obvious and affects mothers more significantly. Cheng et al. reported that 26.9% of mothers of children with cognitive delay reported high depressive symptoms, compared with 17.4% of mothers of typically developing children at 4 years of age.[33] Another body of evidence suggests maternal emotional state during pregnancy influences neurodevelopmental outcome in the child. Maternal anxiety or depression has been associated with altered placental function, reduced infant gray matter density, and worse cognitive function.[34, 35] Therefore, future research may focus on mothers of infants with neurodevelopmental disease to better understand this relationship.

There were several limitations to this study. Some data collected by a survey are subject to information bias. Women may report a more supportive social network than actually exists or omit history of mental health diagnoses. We attempted to control for this by using validated measures where possible and performing chart review to verify reported infant characteristics. Our population was overwhelmingly Hispanic/Latina, and a third of infants were not previously healthy, which limits applicability to other settings. We used a convenience method that could introduce sampling bias. Our hospital's overall patient demographic is 65% Hispanic, which is similar to the 68% sampled in our study. In addition, the proportions of infant diagnoses approximate the overall rates at CHLA, so we feel our sample was fairly representative. There is a general consensus that depression studies have recruitment difficulties.[36] In the unlikely event that all 56 of women who declined to participate were EPDS+, overall proportion of at‐risk mothers would rise to 39%. If our study does show slight underestimation of risk, that would only mean more potential for intervention if screening were mandatory. Another weakness was high loss to follow‐up, which led us to combine the 3‐ and 6‐month follow‐up calls into 1 outcome. Sixty percent of calls used in analysis occurred at 3 months, so long‐term maintenance of improved EPDS scores remains unclear. Although conducting repeat EPDS via phone may affect honest answering of sensitive questions, other studies have used this technique successfully.[4]

CONCLUSION

This is the first study evaluating a screening program for maternal postpartum depression during infant hospitalizations. In our population, risk factors for positive postpartum depression screening were low social support, history of maternal psychiatric diagnosis, and having an infant with neurodevelopmental disease. We believe mothers should receive postpartum depression screening at all medical encounters during the child's first year.

Disclosures: Dr. Trost is an Institutional Career Development Program Scholar through the Southern California Clinical and Translational Science Institute (SC‐CTSI) at the University of Southern California Keck School of Medicine. The content is solely the responsibility of the author(s) and does not represent the official view of the SC‐CTSI. Dr. Trost conceptualized and designed the study, drafted the initial manuscript, and approved the final manuscript as submitted. Dr. Molas‐Torreblanca co‐designed the study, reviewed and revised the manuscript, and approved the final manuscript as submitted. Ms. Man coordinated and supervised hospital data collection, critically reviewed the manuscript, and approved the final manuscript as submitted. Mr. Casillas coordinated and supervised the phone call data collection, critically reviewed the manuscript, and approved the final manuscript as submitted. Ms. Sapir coordinated the referral process for enrolled patients, supervised the design of patient handouts, and critically reviewed and approved the final manuscript as submitted. Dr. Schrager guided study design, supervised the statistical analysis of the final data, critically reviewed and revised the manuscript, and approved the final manuscript as submitted. The authors report no conflicts of interest.

Maternal postpartum depression occurs in 5% to 25% of all mothers, and up to 40% to 60% in high‐risk populations such as low‐income women.[1, 2, 3, 4] Children of affected mothers suffer negative health consequences such as decreased physical growth, poor maternalchild bond, problem behavior, and child abuse.[5, 6, 7] Timely recognition of symptoms and treatment may improve child outcomes.[8] Published guidelines recommend pediatricians screen for postpartum depression at infant 1‐, 2‐, 4‐, and 6‐month outpatient visits.[9] There are no current guidelines for or studies of screening in general inpatient settings, although emergency rooms[10] and neonatal intensive care units (NICUs)[11] have been examined. Pediatric hospitalization may offer an additional opportunity for expanding screening and intervention.

Augmenting outpatient screening practices with additional inpatient screening would have several benefits. Infant health problems have been associated with postpartum depression, and therefore mothers in the hospital may be at higher risk.[12] Inpatient screening would also improve access to mothers not screened as outpatients. Missed screening could occur due to physician discomfort with screening, time constraints during busy office visits, or noncompliance with recommended visit schedules.[13, 14, 15, 16] Finally, inpatient providers would benefit from understanding the psychosocial milieu of children now under their care. Recent studies note hospital discharges may be improved and readmissions reduced by assessing socioeconomic risk factors during hospitalization.[17] The evidence‐based Peds Effective Discharge: Better Handoff to Home through Safer Transitions Better Outcomes by Optimizing Safe Transitions (Pedi‐BOOST) toolkit specifically recommends an assessment of parental psychiatric issues.[18] Postpartum depression strongly correlates with impaired maternalchild bonding,[19] which in turn negatively affects mothers' engagement with healthcare providers.[20] This could impact patient education and recommendations provided during hospitalization.

Therefore, we sought to perform postpartum depression screening during infant hospitalizations. Our primary goal was to determine rate of postpartum depression in our population and proportion of women previously unscreened who could be captured by inpatient screening. We additionally aimed to determine the proportion of women with poor maternalinfant bond. Our next goal was to identify maternal or infant factors associated with positive postpartum depression screening. Finally, we performed follow‐up calls to determine if in‐hospital interventions resulted in formal postpartum depression diagnosis, use of recommended referrals, improved maternalchild bond, and decreased symptoms of depression over time.

METHODS

RESULTS

Out of 366 motherinfant pairs, 56 (15%) refused, and 310 (85%) mothers were fully enrolled (Figure 1A). Mothers had an average age of 28.17 years, were 68.3% Hispanic/Latina by self‐report, and 45.2% were married. Infants were an average of 4.24 months old, 81.9% were born term (>37 weeks), and 64.8% were previously healthy (Table 1).

Figure 1

Eighty‐seven (28%) mothers were EPDS+; 223 (72%) were EPDS. Only 42 mothers reported previous postpartum depression screening since the birth of their most recent child. However, 30 infants were <1 month in age, thus outside recommended screening range. Eliminating these infants revealed a 14.6% rate of appropriate prior screening. Higher EPDS scores were associated with higher (worse) MIB scores by linear regression ( = 0.11, P < 0.001). The vast majority (77%) of mothers scored a 0 or 1 on the MIB scale, indicating good bonding; further statistical comparison using the MIB scale as a secondary outcome was therefore inappropriate.

On bivariate logistic regression, Hispanic/Latina women were less likely to be EPDS+ (odds ratio [OR]: 0.43; 95% CI: 0.23‐0.84) compared to white/Caucasian women. Mothers who identified Spanish as their primary language and took the Spanish EPDS had lower odds of a positive screen (OR: 0.47; 95% CI: 0.25‐0.88). The racial differences did not persist on multivariate analysis (OR: 0.64; 95% CI: 0.30‐1.38) (Table 2). Maternal characteristics identified as potential risk factors for positive screens were poor social support (OR: 3.58; 95% CI: 1.95‐6.59) and history of a prior psychiatric diagnosis (OR: 5.07; 95% CI: 2.65‐9.72). There were no differences in age, number of children or people living in the home, relationship status, or breastfeeding rates by EPDS score.

Infant characteristics were next examined. Children of EPDS+ and EPDS mothers were similar in age, number of prior hospital admissions, gestational age at birth, and overall use of medical equipment (Table 2). To examine the effect of illness leading to hospitalization on EPDS+ risk, discharge diagnoses were collected and grouped into categories. Infants of EPDS+ mothers were more likely hospitalized for neurologic illness (P = 0.008) (see Supporting Table 1 in the online version of this article), but otherwise similar.

We next compared differences in long‐term infant comorbidities. The rate of having any comorbidity was similar between children of EPDS+ and EPDS mothers (39.1% vs 33.6%; P = 0.551). However, children of EPDS+ mothers were more likely to have mental retardation, hydrocephalus, or require ventriculoperitoneal shunt (VPS); however, the overall number of infants with each comorbidity was low. A neurodevelopmental comorbidity variable was created combining mental retardation, cerebral palsy, epilepsy, hydrocephalus, craniosynostosis, and VPS, resulting in 22 (7.1%) unique infants with 1 or more of these conditions. Having an infant with a neurodevelopmental comorbidity was a risk factor for positive postpartum depression screen (OR: 3.41; 95% CI: 1.41‐8.21). This continued to be significant (OR: 2.78; 95% CI: 1.03‐7.52) (Table 2) when controlling for maternal race/ethnicity, psychiatric history, and social support in multivariate logistic regression.

To determine if women screened followed through with recommendations, participants were called 3 and 6 months postenrollment. We attempted to call all women and successfully reached 120; 19 (16%) refused the call. One hundred one of the original 310 enrolled (33%) completed at least 1 follow‐up call; 47 at 3 months, 40 at 6 months, and only 14 (14%) responded at both time points. Due to this response rate, the first call at either 3 or 6 months was used as a single follow‐up time point for statistical analysis. A slightly higher proportion of EPDS‐ mothers (80/223, 36%) completed calls compared to EPDS+ mothers (21/87, 24%; P = 0.047).

Of 21 mothers initially EPDS+ who completed a follow‐up call, 10 (48%) later screened negative. Seven of these 10 (70%) reported discussing postpartum depression with their physician or using provided referral resources in the interim; 1 woman both spoke to a doctor and used a referral resource. One additional woman used resources, but repeat EPDS was still positive (Table 3). Reasons cited for not seeking evaluation included too busy (n = 4) and lost paperwork (n = 1), or no reason was given (n = 2). Mothers utilizing appropriate follow‐up had reduction in scores compared to those not (F(1,19) = 5.743, P = 0.027), although all scores decreased over time (F(1,19) = 11.54, P = 0.0030) (Figure 1B).

Of 80 women initially EPDS, most stayed negative (73/80, 91%), but 7 (9%) became EPDS+. These mothers received education and referral information over the phone, but none completed a subsequent call. Infants of mothers initially EPDS had a higher frequency of hospitalization postenrollment compared to EPDS+ mothers (P = 0.021) (Table 3). Two (33%) mothers who converted from EPDS to EPDS+ had infants readmitted in the follow‐up period.

DISCUSSION

This study demonstrated almost a third of mothers of hospitalized infants are at risk for postpartum depression and most had not been previously screened. Stress due to hospitalization did not seem to falsely elevate EPDS scores; the proportion of EPDS+ mothers matched our prestudy prediction (28% vs 27.9%). Follow‐up calls indicated that EPDS+ mothers not pursuing further evaluation tended to remain EPDS+. Higher (worse) MIB score was strongly correlated to increased EPDS score as expected, supporting screening accuracy. Our results suggest that postpartum depression screening in hospital settings can be used to complement outpatient practice and capture mothers who would otherwise be missed.

Although we were able to screen, it is difficult to know whether this correctly identified mothers with postpartum depression. Only 2 mothers reported subsequent official diagnosis of postpartum depression, and 1 of these was EPDS originally. This reflects weakness of our survey‐based design; we only know if the mother self‐reported a formal diagnosis of postpartum depression, because we do not have access to their medical charts. We also had higher than expected loss to follow up (67%), leaving 66 initially EPDS+ mothers with unknown eventual diagnoses. The EPDS has been validated in multiple populations and has a positive predictive value ranging from 23% to 93%.[23] Therefore, somewhere between 20 and 80 women in our study should meet diagnostic criteria for postpartum depression. A limitation of children's hospital‐based screening with the EPDS is lack of adult‐trained psychiatrists who could immediately follow screening with diagnosis. Such integration may already be possible at community or hospital‐within‐a‐hospital models, and could be trialed at children's hospitals. Regardless, participation in the study seemed to increase mothers' awareness of postpartum depression. Prior to enrollment, only 14.6% of subjects reported discussing postpartum depression with a physician, although recall bias likely contributed to some mothers not remembering a screen. Promisingly, on follow‐up, 37% of called participants reported they discussed postpartum depression with a doctor following their child's hospital discharge.

Our study identified low social support and history of past psychiatric diagnosis as maternal risk factors for EPDS+ screens, which is consistent with previous reports.[29] There was a slight increase in subsequent infant hospitalizations in the EPDS group, which is contrary to reports stating that increased healthcare utilization is associated with postpartum depression.[30] However, most studies have shown an increase in only acute or emergency room care visits[30, 31] and no association between maternal depression and infant hospitalization.[30, 32] In our study, the median number of hospitalizations for both groups was 0, indicating overall low utilization. Because 2 of the mothers who converted from EPDS to EPDS+ had children readmitted, this underscores the benefit of reassessment at each medical encounter. A large proportion of mothers (36.5%) reported that the infant had been previously hospitalized, adding another potential missed screening opportunity. Our study supports others advocating repeated screenings and suggests mothers should be screened at any medical encounter that occurs in the first postpartum year.

We identified neurodevelopmental illness as the major infant characteristic associated with postpartum depression risk. Conversely, Garfield et al. did not find correlation between poorer Neurobiologic Risk Score and increased maternal depression risk in a NICU setting.[11] Perhaps our population of older and mainly full‐term infants makes consequences of neurologic insult more obvious and affects mothers more significantly. Cheng et al. reported that 26.9% of mothers of children with cognitive delay reported high depressive symptoms, compared with 17.4% of mothers of typically developing children at 4 years of age.[33] Another body of evidence suggests maternal emotional state during pregnancy influences neurodevelopmental outcome in the child. Maternal anxiety or depression has been associated with altered placental function, reduced infant gray matter density, and worse cognitive function.[34, 35] Therefore, future research may focus on mothers of infants with neurodevelopmental disease to better understand this relationship.

There were several limitations to this study. Some data collected by a survey are subject to information bias. Women may report a more supportive social network than actually exists or omit history of mental health diagnoses. We attempted to control for this by using validated measures where possible and performing chart review to verify reported infant characteristics. Our population was overwhelmingly Hispanic/Latina, and a third of infants were not previously healthy, which limits applicability to other settings. We used a convenience method that could introduce sampling bias. Our hospital's overall patient demographic is 65% Hispanic, which is similar to the 68% sampled in our study. In addition, the proportions of infant diagnoses approximate the overall rates at CHLA, so we feel our sample was fairly representative. There is a general consensus that depression studies have recruitment difficulties.[36] In the unlikely event that all 56 of women who declined to participate were EPDS+, overall proportion of at‐risk mothers would rise to 39%. If our study does show slight underestimation of risk, that would only mean more potential for intervention if screening were mandatory. Another weakness was high loss to follow‐up, which led us to combine the 3‐ and 6‐month follow‐up calls into 1 outcome. Sixty percent of calls used in analysis occurred at 3 months, so long‐term maintenance of improved EPDS scores remains unclear. Although conducting repeat EPDS via phone may affect honest answering of sensitive questions, other studies have used this technique successfully.[4]

CONCLUSION

This is the first study evaluating a screening program for maternal postpartum depression during infant hospitalizations. In our population, risk factors for positive postpartum depression screening were low social support, history of maternal psychiatric diagnosis, and having an infant with neurodevelopmental disease. We believe mothers should receive postpartum depression screening at all medical encounters during the child's first year.

Disclosures: Dr. Trost is an Institutional Career Development Program Scholar through the Southern California Clinical and Translational Science Institute (SC‐CTSI) at the University of Southern California Keck School of Medicine. The content is solely the responsibility of the author(s) and does not represent the official view of the SC‐CTSI. Dr. Trost conceptualized and designed the study, drafted the initial manuscript, and approved the final manuscript as submitted. Dr. Molas‐Torreblanca co‐designed the study, reviewed and revised the manuscript, and approved the final manuscript as submitted. Ms. Man coordinated and supervised hospital data collection, critically reviewed the manuscript, and approved the final manuscript as submitted. Mr. Casillas coordinated and supervised the phone call data collection, critically reviewed the manuscript, and approved the final manuscript as submitted. Ms. Sapir coordinated the referral process for enrolled patients, supervised the design of patient handouts, and critically reviewed and approved the final manuscript as submitted. Dr. Schrager guided study design, supervised the statistical analysis of the final data, critically reviewed and revised the manuscript, and approved the final manuscript as submitted. The authors report no conflicts of interest.

Maternal postpartum depression occurs in 5% to 25% of all mothers, and up to 40% to 60% in high‐risk populations such as low‐income women.[1, 2, 3, 4] Children of affected mothers suffer negative health consequences such as decreased physical growth, poor maternalchild bond, problem behavior, and child abuse.[5, 6, 7] Timely recognition of symptoms and treatment may improve child outcomes.[8] Published guidelines recommend pediatricians screen for postpartum depression at infant 1‐, 2‐, 4‐, and 6‐month outpatient visits.[9] There are no current guidelines for or studies of screening in general inpatient settings, although emergency rooms[10] and neonatal intensive care units (NICUs)[11] have been examined. Pediatric hospitalization may offer an additional opportunity for expanding screening and intervention.

Augmenting outpatient screening practices with additional inpatient screening would have several benefits. Infant health problems have been associated with postpartum depression, and therefore mothers in the hospital may be at higher risk.[12] Inpatient screening would also improve access to mothers not screened as outpatients. Missed screening could occur due to physician discomfort with screening, time constraints during busy office visits, or noncompliance with recommended visit schedules.[13, 14, 15, 16] Finally, inpatient providers would benefit from understanding the psychosocial milieu of children now under their care. Recent studies note hospital discharges may be improved and readmissions reduced by assessing socioeconomic risk factors during hospitalization.[17] The evidence‐based Peds Effective Discharge: Better Handoff to Home through Safer Transitions Better Outcomes by Optimizing Safe Transitions (Pedi‐BOOST) toolkit specifically recommends an assessment of parental psychiatric issues.[18] Postpartum depression strongly correlates with impaired maternalchild bonding,[19] which in turn negatively affects mothers' engagement with healthcare providers.[20] This could impact patient education and recommendations provided during hospitalization.

Therefore, we sought to perform postpartum depression screening during infant hospitalizations. Our primary goal was to determine rate of postpartum depression in our population and proportion of women previously unscreened who could be captured by inpatient screening. We additionally aimed to determine the proportion of women with poor maternalinfant bond. Our next goal was to identify maternal or infant factors associated with positive postpartum depression screening. Finally, we performed follow‐up calls to determine if in‐hospital interventions resulted in formal postpartum depression diagnosis, use of recommended referrals, improved maternalchild bond, and decreased symptoms of depression over time.

METHODS

RESULTS

Out of 366 motherinfant pairs, 56 (15%) refused, and 310 (85%) mothers were fully enrolled (Figure 1A). Mothers had an average age of 28.17 years, were 68.3% Hispanic/Latina by self‐report, and 45.2% were married. Infants were an average of 4.24 months old, 81.9% were born term (>37 weeks), and 64.8% were previously healthy (Table 1).

Figure 1

Eighty‐seven (28%) mothers were EPDS+; 223 (72%) were EPDS. Only 42 mothers reported previous postpartum depression screening since the birth of their most recent child. However, 30 infants were <1 month in age, thus outside recommended screening range. Eliminating these infants revealed a 14.6% rate of appropriate prior screening. Higher EPDS scores were associated with higher (worse) MIB scores by linear regression ( = 0.11, P < 0.001). The vast majority (77%) of mothers scored a 0 or 1 on the MIB scale, indicating good bonding; further statistical comparison using the MIB scale as a secondary outcome was therefore inappropriate.

On bivariate logistic regression, Hispanic/Latina women were less likely to be EPDS+ (odds ratio [OR]: 0.43; 95% CI: 0.23‐0.84) compared to white/Caucasian women. Mothers who identified Spanish as their primary language and took the Spanish EPDS had lower odds of a positive screen (OR: 0.47; 95% CI: 0.25‐0.88). The racial differences did not persist on multivariate analysis (OR: 0.64; 95% CI: 0.30‐1.38) (Table 2). Maternal characteristics identified as potential risk factors for positive screens were poor social support (OR: 3.58; 95% CI: 1.95‐6.59) and history of a prior psychiatric diagnosis (OR: 5.07; 95% CI: 2.65‐9.72). There were no differences in age, number of children or people living in the home, relationship status, or breastfeeding rates by EPDS score.

Infant characteristics were next examined. Children of EPDS+ and EPDS mothers were similar in age, number of prior hospital admissions, gestational age at birth, and overall use of medical equipment (Table 2). To examine the effect of illness leading to hospitalization on EPDS+ risk, discharge diagnoses were collected and grouped into categories. Infants of EPDS+ mothers were more likely hospitalized for neurologic illness (P = 0.008) (see Supporting Table 1 in the online version of this article), but otherwise similar.

We next compared differences in long‐term infant comorbidities. The rate of having any comorbidity was similar between children of EPDS+ and EPDS mothers (39.1% vs 33.6%; P = 0.551). However, children of EPDS+ mothers were more likely to have mental retardation, hydrocephalus, or require ventriculoperitoneal shunt (VPS); however, the overall number of infants with each comorbidity was low. A neurodevelopmental comorbidity variable was created combining mental retardation, cerebral palsy, epilepsy, hydrocephalus, craniosynostosis, and VPS, resulting in 22 (7.1%) unique infants with 1 or more of these conditions. Having an infant with a neurodevelopmental comorbidity was a risk factor for positive postpartum depression screen (OR: 3.41; 95% CI: 1.41‐8.21). This continued to be significant (OR: 2.78; 95% CI: 1.03‐7.52) (Table 2) when controlling for maternal race/ethnicity, psychiatric history, and social support in multivariate logistic regression.

To determine if women screened followed through with recommendations, participants were called 3 and 6 months postenrollment. We attempted to call all women and successfully reached 120; 19 (16%) refused the call. One hundred one of the original 310 enrolled (33%) completed at least 1 follow‐up call; 47 at 3 months, 40 at 6 months, and only 14 (14%) responded at both time points. Due to this response rate, the first call at either 3 or 6 months was used as a single follow‐up time point for statistical analysis. A slightly higher proportion of EPDS‐ mothers (80/223, 36%) completed calls compared to EPDS+ mothers (21/87, 24%; P = 0.047).

Of 21 mothers initially EPDS+ who completed a follow‐up call, 10 (48%) later screened negative. Seven of these 10 (70%) reported discussing postpartum depression with their physician or using provided referral resources in the interim; 1 woman both spoke to a doctor and used a referral resource. One additional woman used resources, but repeat EPDS was still positive (Table 3). Reasons cited for not seeking evaluation included too busy (n = 4) and lost paperwork (n = 1), or no reason was given (n = 2). Mothers utilizing appropriate follow‐up had reduction in scores compared to those not (F(1,19) = 5.743, P = 0.027), although all scores decreased over time (F(1,19) = 11.54, P = 0.0030) (Figure 1B).

Of 80 women initially EPDS, most stayed negative (73/80, 91%), but 7 (9%) became EPDS+. These mothers received education and referral information over the phone, but none completed a subsequent call. Infants of mothers initially EPDS had a higher frequency of hospitalization postenrollment compared to EPDS+ mothers (P = 0.021) (Table 3). Two (33%) mothers who converted from EPDS to EPDS+ had infants readmitted in the follow‐up period.

DISCUSSION

This study demonstrated almost a third of mothers of hospitalized infants are at risk for postpartum depression and most had not been previously screened. Stress due to hospitalization did not seem to falsely elevate EPDS scores; the proportion of EPDS+ mothers matched our prestudy prediction (28% vs 27.9%). Follow‐up calls indicated that EPDS+ mothers not pursuing further evaluation tended to remain EPDS+. Higher (worse) MIB score was strongly correlated to increased EPDS score as expected, supporting screening accuracy. Our results suggest that postpartum depression screening in hospital settings can be used to complement outpatient practice and capture mothers who would otherwise be missed.

Although we were able to screen, it is difficult to know whether this correctly identified mothers with postpartum depression. Only 2 mothers reported subsequent official diagnosis of postpartum depression, and 1 of these was EPDS originally. This reflects weakness of our survey‐based design; we only know if the mother self‐reported a formal diagnosis of postpartum depression, because we do not have access to their medical charts. We also had higher than expected loss to follow up (67%), leaving 66 initially EPDS+ mothers with unknown eventual diagnoses. The EPDS has been validated in multiple populations and has a positive predictive value ranging from 23% to 93%.[23] Therefore, somewhere between 20 and 80 women in our study should meet diagnostic criteria for postpartum depression. A limitation of children's hospital‐based screening with the EPDS is lack of adult‐trained psychiatrists who could immediately follow screening with diagnosis. Such integration may already be possible at community or hospital‐within‐a‐hospital models, and could be trialed at children's hospitals. Regardless, participation in the study seemed to increase mothers' awareness of postpartum depression. Prior to enrollment, only 14.6% of subjects reported discussing postpartum depression with a physician, although recall bias likely contributed to some mothers not remembering a screen. Promisingly, on follow‐up, 37% of called participants reported they discussed postpartum depression with a doctor following their child's hospital discharge.

Our study identified low social support and history of past psychiatric diagnosis as maternal risk factors for EPDS+ screens, which is consistent with previous reports.[29] There was a slight increase in subsequent infant hospitalizations in the EPDS group, which is contrary to reports stating that increased healthcare utilization is associated with postpartum depression.[30] However, most studies have shown an increase in only acute or emergency room care visits[30, 31] and no association between maternal depression and infant hospitalization.[30, 32] In our study, the median number of hospitalizations for both groups was 0, indicating overall low utilization. Because 2 of the mothers who converted from EPDS to EPDS+ had children readmitted, this underscores the benefit of reassessment at each medical encounter. A large proportion of mothers (36.5%) reported that the infant had been previously hospitalized, adding another potential missed screening opportunity. Our study supports others advocating repeated screenings and suggests mothers should be screened at any medical encounter that occurs in the first postpartum year.

We identified neurodevelopmental illness as the major infant characteristic associated with postpartum depression risk. Conversely, Garfield et al. did not find correlation between poorer Neurobiologic Risk Score and increased maternal depression risk in a NICU setting.[11] Perhaps our population of older and mainly full‐term infants makes consequences of neurologic insult more obvious and affects mothers more significantly. Cheng et al. reported that 26.9% of mothers of children with cognitive delay reported high depressive symptoms, compared with 17.4% of mothers of typically developing children at 4 years of age.[33] Another body of evidence suggests maternal emotional state during pregnancy influences neurodevelopmental outcome in the child. Maternal anxiety or depression has been associated with altered placental function, reduced infant gray matter density, and worse cognitive function.[34, 35] Therefore, future research may focus on mothers of infants with neurodevelopmental disease to better understand this relationship.

There were several limitations to this study. Some data collected by a survey are subject to information bias. Women may report a more supportive social network than actually exists or omit history of mental health diagnoses. We attempted to control for this by using validated measures where possible and performing chart review to verify reported infant characteristics. Our population was overwhelmingly Hispanic/Latina, and a third of infants were not previously healthy, which limits applicability to other settings. We used a convenience method that could introduce sampling bias. Our hospital's overall patient demographic is 65% Hispanic, which is similar to the 68% sampled in our study. In addition, the proportions of infant diagnoses approximate the overall rates at CHLA, so we feel our sample was fairly representative. There is a general consensus that depression studies have recruitment difficulties.[36] In the unlikely event that all 56 of women who declined to participate were EPDS+, overall proportion of at‐risk mothers would rise to 39%. If our study does show slight underestimation of risk, that would only mean more potential for intervention if screening were mandatory. Another weakness was high loss to follow‐up, which led us to combine the 3‐ and 6‐month follow‐up calls into 1 outcome. Sixty percent of calls used in analysis occurred at 3 months, so long‐term maintenance of improved EPDS scores remains unclear. Although conducting repeat EPDS via phone may affect honest answering of sensitive questions, other studies have used this technique successfully.[4]

CONCLUSION

This is the first study evaluating a screening program for maternal postpartum depression during infant hospitalizations. In our population, risk factors for positive postpartum depression screening were low social support, history of maternal psychiatric diagnosis, and having an infant with neurodevelopmental disease. We believe mothers should receive postpartum depression screening at all medical encounters during the child's first year.

Disclosures: Dr. Trost is an Institutional Career Development Program Scholar through the Southern California Clinical and Translational Science Institute (SC‐CTSI) at the University of Southern California Keck School of Medicine. The content is solely the responsibility of the author(s) and does not represent the official view of the SC‐CTSI. Dr. Trost conceptualized and designed the study, drafted the initial manuscript, and approved the final manuscript as submitted. Dr. Molas‐Torreblanca co‐designed the study, reviewed and revised the manuscript, and approved the final manuscript as submitted. Ms. Man coordinated and supervised hospital data collection, critically reviewed the manuscript, and approved the final manuscript as submitted. Mr. Casillas coordinated and supervised the phone call data collection, critically reviewed the manuscript, and approved the final manuscript as submitted. Ms. Sapir coordinated the referral process for enrolled patients, supervised the design of patient handouts, and critically reviewed and approved the final manuscript as submitted. Dr. Schrager guided study design, supervised the statistical analysis of the final data, critically reviewed and revised the manuscript, and approved the final manuscript as submitted. The authors report no conflicts of interest.