(856) Association of Co-Occurring Chronic Hypertension and Oligohydramnios on Neonatal Outcomes

Objective: Oligohydramnios has been associated with uteroplacental insufficiency and occurs at a higher rate among patients with chronic hypertension. However, the additional risk associated with oligohydramnios and adverse neonatal outcomes has not been well elucidated in this population, which is already at higher risk of adverse outcomes. The objective of this study was to investigate the association between oligohydramnios and chronic hypertension on neonatal outcomes. 

Study Design: This is a retrospective cohort study comparing pregnant persons with chronic hypertension who had oligohydramnios versus no oligohydramnios. We used a California cohort of singleton, non-anomalous pregnancies with late preterm or term births (34 to 41 weeks) who delivered between 2008 and 2020. Chi-squared and multivariable logistic regression models were used for statistical analysis with a p-value of 0.05. 

Results: Of the 434,362 pregnant persons with chronic hypertension who met inclusion criteria, 14,867 had oligohydramnios (3.4%). Pregnant persons with chronic hypertension with oligohydramnios were significantly different by race/ethnicity, body mass index, and parity compared to those without oligohydramnios. The rate of preexisting diabetes was similar between groups (4.3% vs 4.0%, P = 0.13). Oligohydramnios was associated with a higher adjusted odds of preterm birth (aOR 1.58; 1.51-1.65), NICU admission (aOR 1.13; 95% CI 1.07-1.19), small for gestational age (aOR 2.43; 95% CI 2.34-2.53), and stillbirth (aOR 1.81; 95% CI 1.05-3.12).

Conclusion: This study demonstrates that oligohydramnios with chronic hypertension is associated with adverse neonatal outcomes. Our study can enhance patient knowledge and provider counseling to mitigate neonatal impacts of co-occurring diagnoses.