Association between Stillbirth at or after 23 weeks gestation and Acute Psychiatric Illness within One Year of Delivery

Abstract Background Stillbirth has been associated with emotional and psychological symptoms. The association between stillbirth and diagnosed postpartum psychiatric illness is less well-known. Objectives To determine whether women have higher risk of developing clinician-diagnosed psychiatric morbidity in the year after stillbirth versus livebirth. Study Design This retrospective cohort study used International Classification of Diseases, 9 th Revision, Clinical Modification (ICD-9-CM) diagnosis and procedure codes to identify participants, exposures, and outcomes within the Florida State Inpatient and State Emergency Department (ED) Databases. The first delivery of female Florida residents aged 13 to 55 years old from 2005 to 2014 was included; women with ICD-9-CM coding for psychiatric illness or substance use during pregnancy were excluded. The exposure was an ICD-9-CM diagnosis code during delivery hospitalization of a stillbirth ≥ 23 weeks gestation. The primary outcome was a primary or secondary ICD-9-CM diagnosis code during an ED encounter or inpatient admission within one year of delivery for a composite of psychiatric morbidity: suicide attempt, depression, anxiety, post-traumatic stress disorder, psychosis, acute stress reaction, or adjustment disorder. The secondary outcome was a substance use composite: drug or alcohol use or dependence. We compared outcomes after delivery of stillbirth versus livebirth using multivariable logistic regression adjusting for maternal sociodemographic factors, medical comorbidities, and severe intrapartum morbidity. We also used Cox proportional hazard models and tested for violation of the proportional hazard assumption to identify the highest risk time within the year after stillbirth delivery for the primary outcome, adjusting for the same factors and morbidities as in the logistic regression model. Results 8292 women with stillborn singletons and 1,194,758 with liveborn singletons were included. Within one year of hospital discharge after stillbirth, 4.0% (n=331) of women had an ED encounter or inpatient admission coded for psychiatric morbidity: the risk was nearly 2.5 times higher compared to livebirth (1.6% (n=19,746); adjusted odds ratio (aOR) 2.47 (95% Confidence Interval (CI) 2.20 – 2.77)). Women also had higher risk of having an ED encounter or inpatient admission coded for drug or alcohol use or dependence in the year following delivery of stillbirth versus livebirth (124 (1.5%) versus 7033 (0.6%); aOR 2.41 (95% CI 1.99 – 2.90)). Cox proportional hazard modeling suggested that highest risk interval for postpartum psychiatric illness was within four months of stillbirth delivery (adjusted hazard ratio (aHR) 3.26 (95% CI 2.63 – 4.04), though the risk remained high during the four to twelve months after delivery (aHR 2.42 (95% CI 2.13 – 2.76). Conclusions Coding for psychiatric illness or substance misuse in ED visits or hospital admissions in the year after delivery of livebirths was not uncommon, corresponding to nearly two per 100 women. However, having a stillbirth was associated with increased risk of both psychiatric morbidity (corresponding to 1 per 25 women) and substance misuse (corresponding to 3 in 100 women), with the highest risk of postpartum psychiatric morbidity occurring from delivery until four months postpartum.