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

Background: Having twins is associated with more depressive symptoms than having singletons. However, the association between having twins and psychiatric morbidity requiring emergency department visit or inpatient hospitalization is less well known. Objective: This study aimed to determine whether women have higher risk of having a psychiatric diagnosis at an emergency department visit or inpatient admission in the year after having twins vs singletons. Study Design: This retrospective cohort study used International Classification of Diseases, Ninth Revision, Clinical Modification diagnosis and procedure codes within the Florida State Inpatient Database and State Emergency Department Database, which have an encrypted identifier allowing nearly all inpatient and emergency department encounters statewide to be linked to the medical record. The first delivery of Florida residents at the age of 13 to 55 years from 2005 to 2014 was included, regardless of parity; women with International Classification of Diseases, Ninth Revision, Clinical Modification coding for psychiatric illness or substance misuse during pregnancy or for stillbirth or higher-order gestations were excluded. The exposure was an International Classification of Diseases, Ninth Revision, Clinical Modification code during delivery hospitalization of live-born twins. The primary outcome was an International Classification of Diseases, Ninth Revision, Clinical Modification code during an emergency department encounter or inpatient admission within 1 year of delivery for a psychiatric morbidity composite (suicide attempt, depression, anxiety, posttraumatic stress disorder, psychosis, acute stress reaction, or adjustment disorder). The secondary outcome was drug or alcohol use or dependence within 1 year of delivery. We compared outcomes after delivery of live-born twins with singletons using multivariable logistic regression adjusting for sociodemographic and medical factors. We tested for interactions between independent variables in the primary model and conducted sensitivity analyses stratifying women by insurance type and presence of severe intrapartum morbidity or medical comorbidities. Results: A total of 17,365 women who had live-born twins and 1,058,880 who had singletons were included. Within 1 year of birth, 1.6% of women delivering twins (n=270) and 1.6% of women delivering singletons (n=17,236) had an emergency department encounter or inpatient admission coded for psychiatric morbidity (adjusted odds ratio, 1.00; 95% confidence interval, 0.88–1.14). Coding for drug or alcohol use or dependence in an emergency department encounter or inpatient admission in the year after twin vs singleton delivery was also similar (n=96 [0.6%] vs n=6222 [0.6%]; adjusted odds ratio, 1.11; 95% confidence interval, 0.91–1.36). However, women with public health insurance were more likely to be coded for drug or alcohol use or dependence after twin than singleton delivery (n=75 [1.2%] vs n=4858 [1.0%]; adjusted odds ratio, 1.27; 95% confidence interval, 1.01–1.60). Women with ≥1 medical comorbidity, severe maternal morbidity, or low income also had an increased risk of psychiatric morbidity after twin delivery (comorbidities, n=7438 [42.8%]; adjusted odds ratio, 1.30; 95% confidence interval, 1.25–1.34; severe maternal morbidity, n=940 [5.4%]; adjusted odds ratio, 1.65; 95% confidence interval, 1.49–1.81; lowest income quartile, n=4409 [26.8%]; adjusted odds ratio, 1.31; 95% confidence interval, 1.23–1.40; second-lowest income quartile, n=4770 [29.0%]; adjusted odds ratio, 1.34; 95% confidence interval, 1.26–1.43). Conclusion: Overall, diagnostic codes for psychiatric illness or substance misuse in emergency department visits or hospital admissions in the year after twin vs singleton delivery are similar. However, women with who are low income or have public health insurance, comorbidities, or severe maternal morbidity are at an increased risk of postpartum psychiatric morbidity after twin vs singleton delivery.