The association between preterm birth and postpartum mental health care utilization among California birthing people.

BACKGROUND While birthing person's mental health conditions such as postpartum depression are common, little is known about how mental health care utilization varies postpartum based on whether or not an infant is born preterm. OBJECTIVE To determine whether preterm birth is associated with postpartum inpatient and emergency mental health care utilization. STUDY DESIGN Data were obtained from a database of liveborn neonates born in California between the years of 2011-2017. The sample included all people giving birth to singleton infants between the gestational age of 20-44 weeks. Preterm birth was defined as <37 weeks gestation. Emergency department visits and hospitalizations with a mental health diagnosis within 1 year after birth were identified using International Classification of Diseases codes. Logistic regression was used to compare relative risks of health care utilization among people giving birth to preterm infants versus term infants, adjusting for the following covariates: age, race/ethnicity, parity, prior preterm birth, body mass index, tobacco use, alcohol/drug use, hypertension, diabetes, adequacy of prenatal care, education, insurance payer, and the presence of a mental health diagnosis before birth. Results were then stratified by mental health diagnosis prior to birth to determine whether associations varied based on mental health history. RESULTS Of our sample of 3,067,069 births, 6.7% were preterm. In fully adjusted models, compared to people giving birth to term infants, people giving birth to preterm infants had a 1.5 times (RR, 95% confidence interval [CI] 1.4-1.7) and 1.3 times (95% CI 1.2-1.4) increased risk of being hospitalized with a mental health diagnosis within 3 months and 1 year postpartum, respectively. People giving birth to preterm infants also had a 1.4 times (95% CI 1.3-1.5) and 1.3 times (95% CI 1.2-1.4) increased risk of visiting the emergency department for a mental health diagnosis within 3 months and 1 year after birth, respectively. Stratifying by preexisting mental health diagnosis, preterm birth was associated with an elevated risk of mental health care utilization for people with and without a prior mental health diagnosis. CONCLUSIONS We found that preterm birth is an independent risk factor for postpartum mental health care utilization. Our findings suggest that screening for and providing mental health resources to birthing people postpartum is crucial, particularly among people giving birth to preterm infants, regardless of mental health history.