Association between delivering live-born twins and acute psychiatric illness within 1 year of delivery

Prenatal exposure to poly- and perfluoroalkyl substances and postpartum depression in women with twin pregnancies

BACKGROUND

Women with multiple pregnancies are vulnerable to experience postpartum depression (PPD). Emerging evidence indicates an association between poly- and perfluoroalkyl substances (PFAS) exposure and PPD in women delivering singletons. The health risks of PFAS may also be present in women delivering twins.

OBJECTIVE

To estimate the impacts of prenatal PFAS exposure on the risk of PPD in women with twin pregnancies.

METHODS

Our study included 150 mothers who gave birth to twins and were enrolled in the Wuhan Twin Birth Cohort. The concentrations of maternal plasma PFAS were measured in each trimester and averaged. Eight individual PFAS were included in analyses. We used Edinburgh Postnatal Depression Scale to evaluate maternal depression at early pregnancy and 1 and 6 months after childbirth. The outcome was dichotomized using a cutoff value of ≥10 for main analyses. Associations were examined using multiple informant models and modified Poisson regressions. PFAS mixture effects were estimated using quantile g-computation.

RESULTS

Using quantile g-computation models, a quartile increase in the PFAS mixture during the first, second, third, and average pregnancy was significantly associated with a relative risk (RR) of 1.73 (95% CI: 1.42, 2.12), 1.54 (95% CI: 1.27, 1.84), 1.75 (95% CI: 1.49, 2.08), and 1.63 (95% CI: 1.35, 1.97) for PPD at 6 months after childbirth, respectively. The results of the single-PFAS models also indicated significant positive associations between individual PFAS and PPD at both 1 and 6 months.

CONCLUSIONS

The first study of women with twin pregnancies suggests that prenatal exposure to PFAS increases PPD risk up to 6 months postpartum. Twin pregnant women should receive long-term follow-up after delivery and extensive social support.

Twin pregnancy and severe maternal mental illness: a Canadian population-based cohort study

Twin pregnancy is a risk factor for postpartum depression and anxiety. Whether this translates into a higher risk of severe maternal mental illness in the short-term or long-term is unknown. This study was a population-based retrospective cohort study, using linked health administrative databases for the entire province of Ontario, Canada. Included were primiparas aged 15-50 years with a twin vs. singleton hospital livebirth, between January 1, 2003, and March 31, 2019. Propensity-score inverse probability of treatment weights accounted for potential confounding. The primary outcome of severe mental illness comprised a composite of an emergency department visit or hospitalization for mental illness or self-injury, or death by suicide, assessed in the first year after birth, and in long-term follow-up, up to 17 years thereafter. Fifteen thousand twenty-four twin and 796,804 (15,022 weighted) singleton births were included, with a mean (IQR) duration of follow-up of 9 (5-13) years. After weighting, the mean (SD) maternal age was 31.3 (5.5) years. In the first 365 days postpartum, severe mental illness occurred at rates of 10.5 and 8.7 per 1000 person-years in twin and singleton mothers, respectively, corresponding to a hazard ratio (HR) of 1.21 (95% CI 1.07-1.47). From 366 days onward, the corresponding figures were 5.9 and 6.1 per 1000 person-years (HR 0.96, 95% CI 0.89-1.04). Individuals with a twin birth appear to experience an increased risk for severe mental illness in the first year postpartum, but not thereafter. This suggests a potential need for targeted counselling and mental health services for mothers within the first year after birth.