Researchers from Rutgers University, Princeton University and the University of California, San Francisco found an association between maternal depressive symptoms identified immediately after childbirth and infant mortality in a study of 414,890 New Jersey births. Published September 2 in JAMA Network Open, the research examined deaths during the first 364 days after birth.

Key Takeaways

• A study published in JAMA Network Open found that maternal depressive symptoms identified immediately after childbirth were associated with a higher risk of infant mortality.
• Researchers analyzed 414,890 singleton births in New Jersey from 2016 through 2020.
• Mothers with an Edinburgh Postnatal Depression Scale score of 10 or higher were classified as having documented depressive symptoms.
• Infant mortality was 7.2 deaths per 1,000 births among infants whose mothers had depressive symptoms, compared with 2.0 per 1,000 among those without documented symptoms.
• The observational study found an association but did not prove that postpartum depression causes infant death.

JAMA Study Examines Postpartum Depression and Infant Mortality

The population-based retrospective cohort study examined whether maternal depressive symptoms identified during the immediate postpartum period were associated with the risk of infant death. Researchers used New Jersey birth records from 2016 through 2020 and linked them with death records from 2016 through 2021.

The final complete-case analysis included 414,890 singleton infants. Of those infants, 413,984 did not die during the study’s defined follow-up period, while 906 died within 364 days of birth. The infants included 212,760 males and 202,130 females.

The study defined maternal depressive symptoms using the 10-item Edinburgh Postnatal Depression Scale, commonly known as the EPDS. A score of 10 or higher was classified as indicating depressive symptoms under the clinical threshold used by New Jersey hospitals. Screening takes place in hospitals after delivery and before discharge.

Among the mothers represented in the analysis, 15,905, or 3.8%, had documented depressive symptoms. The researchers compared infant outcomes among mothers with and without those symptoms while accounting for maternal and infant demographic and socioeconomic characteristics.

The study was conducted in New Jersey because the state requires hospitals to screen for maternal depressive symptoms during the immediate postpartum period. That requirement allowed researchers to use screening results rather than relying only on formal depression diagnoses recorded in medical records.

The findings add to existing coverage of maternal health and postpartum care, including the role of emotional and mental health support after childbirth.

Researchers Analyze 414,890 New Jersey Births

Researchers analyzed 483,138 singleton births to New Jersey residents, with 414,890 included in the final complete-case analysis. The study excluded records missing data needed for the primary analysis; 39,086 infants (8.1%) had mothers without a documented EPDS score.

The analysis adjusted for maternal age, race and ethnicity, nativity, parity, education, insurance, WIC participation, neighborhood income, infant sex and birth year. Researchers also considered tobacco and substance use, hypertension, diabetes, delivery type, low birth weight and preterm birth.

The primary outcome was death within 364 days of birth, with a separate analysis examining deaths from 8 through 364 days. Among the 906 infant deaths in the complete analysis, 107 involved mothers with documented depressive symptoms.

Infant mortality was 7.2 deaths per 1,000 births among mothers with depressive symptoms, compared with 2.0 per 1,000 among those without documented symptoms. Infants who died were also more likely to have mothers with lower educational attainment, public or other insurance, WIC participation, tobacco use, hypertension and lower neighborhood income; low birth weight and preterm birth were also more common.

Edinburgh Postnatal Depression Scale Screening

The EPDS score was treated as a measure of depressive symptoms rather than a definitive diagnosis of postpartum depression. The researchers used both the threshold of 10 or higher and continuous EPDS scores in their analyses.

The timing of screening was also relevant to the study. New Jersey hospitals generally administer the screening before maternal discharge, but depressive symptoms can develop later in the postpartum period. The researchers therefore noted that immediate postpartum screening does not capture every case of postpartum depression that may occur after childbirth.

Depressive Symptoms Associated With Higher Infant Mortality Risk

In the unadjusted analysis, infants born to mothers with depressive symptoms had a relative risk of infant death of 3.36 compared with infants whose mothers did not have documented symptoms. After adjustment for maternal and infant demographic and socioeconomic characteristics, the adjusted relative risk was 2.89, with a 95% confidence interval of 2.36 to 3.54.

The researchers conducted an additional model that included maternal and infant risk factors such as low birth weight and preterm birth. That model produced an adjusted relative risk of 1.97, with a 95% confidence interval of 1.61 to 2.42. The researchers considered the model adjusting for demographic and socioeconomic characteristics to be their preferred model because some additional risk factors could potentially fall along the pathway between depressive symptoms and infant death.

The association was also present when researchers limited the outcome to infant deaths occurring between eight and 364 days after birth. In the preferred adjusted model, the relative risk was 2.10, with a 95% confidence interval of 1.56 to 2.81.

The study’s findings also relate to broader women’s mental and physical health, including mental health concerns associated with pregnancy and the postpartum period.

Researchers examined the association across maternal race and ethnicity, educational level, insurance status and infant preterm birth. They reported higher relative risks across those subgroups, with no statistically significant differences in the association across most of the characteristics examined.

The researchers also examined infant deaths according to leading causes. Maternal depressive symptoms were associated with deaths attributed to prematurity-related conditions, perinatal conditions, congenital malformations and chromosomal abnormalities, and sudden infant death syndrome.

For deaths from prematurity-related conditions, the adjusted relative risk was 4.07. The adjusted relative risk was 5.12 for deaths associated with perinatal conditions, 3.56 for congenital malformations and chromosomal abnormalities, and 2.08 for sudden infant death syndrome.

For deaths occurring between eight and 364 days after birth, the association remained for prematurity-related conditions, perinatal conditions and sudden infant death syndrome. The adjusted relative risks were 4.85, 4.68 and 2.13, respectively.

Infant Death Risks Differ Across Major Causes

Prematurity-related conditions accounted for 213 of the 906 infant deaths (23.5%), followed by perinatal conditions with 154 deaths, congenital malformations and chromosomal abnormalities with 134, and sudden infant death syndrome with 118.

The association between maternal depressive symptoms and infant mortality remained after adjusting for maternal and infant characteristics, with sensitivity analyses producing similar results. Researchers noted that maternal depression may be associated with physiological changes, adverse birth outcomes, infant care practices and health care use, but the study did not establish a specific mechanism.

Because the study was observational, the findings do not prove that maternal depressive symptoms caused infant deaths. Researchers also noted that some mothers may develop depressive symptoms after the immediate postpartum screening period and that unmeasured factors could have affected the results.

Study Limitations Affect Interpretation of the Findings

The researchers identified several limitations that affect how the findings should be interpreted. First, the study relied on data from New Jersey, so the results may not apply directly to populations in other states.

Second, 8.1% of infants in the larger study population had mothers without a documented EPDS score. The missing screening records may have resulted from patients declining screening or from administrative errors. Multiple-imputation analyses produced estimates similar to the primary findings, but those methods depend on assumptions about the missing data.

The researchers also could not match every infant death record to a birth record. Of 2,094 infant deaths identified in the death records between 2016 and 2021, 1,608 had matching birth records, and 1,413 of those were singleton infants included in the analysis. Additional sensitivity and bounds analyses were conducted to assess the potential effect of unmatched deaths.

Another limitation involved the timing of depressive symptoms. The prevalence identified through immediate postpartum screening was lower than national estimates cited by the researchers, which they attributed in part to the timing of the screening. Some mothers develop depressive symptoms later in the postpartum period and would therefore not necessarily be identified through the hospital screening used in this study.

The researchers also said the analysis could not account for unobserved confounding. In addition, mothers may have been aware of infant health problems present at birth that increased the risk of death, and that knowledge could have been associated with depressive symptoms. The researchers conducted additional analyses, including examinations of deaths from sudden infant death syndrome, but said future research is needed to address these issues more fully.

The study authors reported that their findings support further research into the relationship between maternal depressive symptoms and infant mortality. They also identified maternal depression screening and interventions for people with depressive symptoms as areas relevant to maternal and infant health, while the study itself does not establish which interventions would reduce infant mortality.

Frequently Asked Questions

Can postpartum depression increase the risk of infant mortality?

The study found an association between maternal depressive symptoms identified immediately after childbirth and a higher risk of infant death before age 1. It did not establish that postpartum depression directly causes infant mortality.

What did the new postpartum depression study find?

Researchers found that infants whose mothers had depressive symptoms had a higher adjusted relative risk of death within 364 days after birth. In the preferred adjusted model, the relative risk was 2.89 compared with infants whose mothers did not have documented depressive symptoms.

How was postpartum depression measured in the study?

Researchers used the Edinburgh Postnatal Depression Scale, a 10-item screening tool. An EPDS score of 10 or higher was classified as indicating maternal depressive symptoms for the study.

How many births were included in the study?

The complete-case analysis included 414,890 singleton infants born in New Jersey between 2016 and 2020. Birth records were linked with death records to examine infant mortality through 364 days after birth.

Did the study prove that postpartum depression causes infant death?

No. The research was a retrospective observational cohort study and identified an association rather than proving causation. Researchers also reported limitations involving missing screening data, unmatched death records, the timing of depressive symptoms and unmeasured confounding.

Disclaimer:
This article is for informational and educational purposes only and should not be considered medical advice, diagnosis or treatment. Anyone experiencing symptoms of postpartum depression or concerns about maternal or infant health should consult a qualified healthcare professional for appropriate evaluation and care.