Postpartum readmission risk: a comparison between stillbirths and live births.

BACKGROUND: Stillbirth occurs more commonly among pregnant people with comorbid conditions and obstetrical complications. Stillbirth also independently increases maternal morbidity and imparts a psychosocial hazard when compared with live birth. These distinct needs and burden may increase the risk for postpartum readmission after stillbirth. OBJECTIVE: This study aimed to examine the risk for maternal postpartum readmission after stillbirth in comparison with live birth and to identify indications for readmission and the associated risk factors. STUDY DESIGN: This was a retrospective cohort of patients with singleton stillbirths or live births, delivered at ≥20 weeks' gestation, who were identified from the 2019 Nationwide Readmissions Database. The primary outcome was all-cause readmission within 6 weeks of discharge from the childbirth hospitalization. The association between stillbirth (vs live birth) and risk for readmission was assessed using multivariable regression models with adjustment for maternal age, sociodemographic characteristics, maternal and obstetrical conditions, and delivery characteristics. Within the stillbirth group, risk factors for readmission were further examined using multivariable regression. The secondary outcomes included principal indication for readmission (categorized based on principal diagnosis code of the readmission hospitalization) and timing of readmission (number of weeks after childbirth hospitalization). Differences in these secondary outcomes were compared between the stillbirth and live birth groups using chi-square tests. All analyses accounted for the complex sample design to generate nationally representative estimates. RESULTS: Postpartum readmission occurred in 2.7% of 16,636 patients with stillbirths, whereas it occurred in 1.6% of 2,870,677 patients with live births (unadjusted risk ratio, 1.65; 95% confidence interval, 1.47-1.86). The higher risk for readmission after stillbirth (vs live birth) persisted after adjusting for maternal, obstetrical, and delivery characteristics (adjusted risk ratio, 1.27; 95% confidence interval, 1.11-1.46). The distribution of principal indication for readmission differed after stillbirth and after live birth and included hypertension (30.2% vs 39.5%; unadjusted risk ratio, 0.76; 95% confidence interval, 0.63-0.93), mental health or substance use disorders (6.8% vs 3.6%; unadjusted risk ratio, 1.90; 95% confidence interval, 1.15-3.16), and venous thromboembolism (5.8% vs 2.0%; unadjusted risk ratio, 2.87; 95% confidence interval, 1.60-5.17). Among patients with stillbirths, 56.0% of readmissions occurred within 1 week, 71.8% within 2 weeks, and 88.1% within 4 weeks; the timing of readmission did not differ significantly between the stillbirth and live birth cohorts. Pregestational diabetes (adjusted risk ratio, 1.87; 95% confidence interval, 1.20-2.93), gestational diabetes (adjusted risk ratio, 1.67; 95% confidence interval, 1.03-2.71), hypertensive disorders of pregnancy (adjusted risk ratio, 1.80; 95% confidence interval, 1.31-2.47), obesity (adjusted risk ratio, 1.46; 95% confidence interval, 1.01-2.12), and primary cesarean delivery (adjusted risk ratio, 1.74; 95% confidence interval, 1.17-2.58) were associated with a higher risk for readmission after stillbirth, whereas higher household income was associated with a lower risk for readmission (eg, adjusted risk ratio for income ≥$82,000 vs $1-$47,999, 0.48; 95% confidence interval, 0.30-0.77). CONCLUSION: When compared with live births, the risk for postpartum readmission was higher after stillbirths, even after adjustment for differences in the patient demographic and clinical characteristics. Readmission for mental health or substance use disorders and venous thromboembolism is more common after stillbirths than after live births.

Co-existing chronic hypertension and hypertensive disorders of pregnancy and associated adverse pregnancy outcomes.

OBJECTIVE: Chronic hypertension (CHTN) causes vascular damage and resistance in the pregnant person and malperfusion in the placenta which may worsen the endothelial dysfunction of hypertensive disorders of pregnancy (HDP). These conditions frequently co-exist. A cumulative effect has been inconsistently demonstrated in prior studies, and it is unclear how co-existing hypertensive conditions affect pregnancy outcomes. We sought to examine maternal and neonatal outcomes in pregnancies affected by co-existing CHTN and HDP and compare these outcomes to those of pregnancies which were unaffected or affected by either condition alone. METHODS: This is a retrospective cohort study of singleton deliveries at a single institution 1 October 2013 to 1 October 2021. Data were extracted from the electronic medical record using standardized definitions and billing and diagnosis codes. Pregnant people with no evidence of hypertensive condition were compared to those with CHTN only, HDP only, and co-existing CHTN and HDP. Demographics, baseline clinical data, and use of aspirin or antihypertensive medications were assessed. Maternal outcomes included cesarean delivery, critical range blood pressure, intensive care unit (ICU) admission, and death. Neonatal outcomes included preterm birth <37 weeks' gestation, small for gestational age (SGA) birthweight, ICU admission, and a morbidity composite. Bivariate tests of association were performed using Chi-square test. Crude and adjusted odds ratios (aORs) were calculated using logistic regression for three maternal and four neonatal outcomes. Descriptive statistics and multivariable analyses were performed. RESULTS: Of 40,840 eligible people, 1451 (3.6%) had CHTN only; 5213 (12.8%) had HDP only; and 1890 (4.6%) had co-existing CHTN and HDP. Though odds of adverse maternal and neonatal outcomes were significantly increased for all hypertensive groups relative to the unaffected referent group, co-existing CHTN and HDP had the highest odds of cesarean delivery (aOR 1.60; 95% confidence interval (CI) 1.45-1.77), critical blood pressure (OR 41.54; 95% CI 35.96-47.99), maternal ICU admission or death (aOR 3.52; 95% CI 2.65-4.67), preterm birth (aOR 2.76; 95% CI 2.41-3.16), and SGA birthweight (aOR 1.61; 95% CI 1.39-1.87). CONCLUSIONS: Hypertensive disorders of pregnancy in the setting of CHTN are associated with the highest odds of serious consequences on the pregnant person and neonate independent of maternal comorbidities and prematurity. Antihypertensive medication use lowers the odds of some adverse outcomes. Patients should be informed of heightened risks, but optimal management remains unclear.