(424) Pregnancy latency and fetal growth restriction in expectant management of severe pre-eclampsia

Pre-eclampsia leads to significant maternal-fetal complications and is associated with fetal growth restriction (FGR). We investigated the impact of pre-existing FGR at hospital admission on latency to delivery among patients undergoing expectant management of severe pre-eclampsia (SPREX).

Study Design: Retrospective cohort study of patients with SPREX diagnosed < 32 weeks’ gestational age (GA) admitted to a single tertiary center (2013-2019) who were candidates for expectant management. We excluded patients with contraindications to expectant management and < 2 days of latency. An upper threshold of 32 weeks’ GA at diagnosis was used to allow for latency. Primary outcome was latency, measured in days from diagnosis to delivery. Secondary outcomes included latency >7 and >14 days, and maternal/obstetric outcomes. Bivariate statistics compared characteristics and logistic regression estimated adjusted odds ratios (aOR) with 95% confidence intervals (95%CI).

Results: Of 135 pregnancies with SPREX < 32 weeks, 47 (35%) had FGR at admission. Demographic traits did not differ between patients with and without FGR (Table 1). Pregnancies with FGR had an earlier admission GA (27.4 weeks vs 29.1 weeks, p=0.01), SPREX diagnosis < 28 weeks (57% vs 36%, p=0.02), and abnormal dopplers (62% vs 9%, p< 0.001) compared to pregnancies without FGR. Median latency did not differ (Table 2). Even after controlling for admission GA, latency >7 days (aOR 0.68, 95%CI:0.32-1.44) and >14 days (aOR 0.45, 95%CI:0.18-1.11) were not different with FGR. No differences were observed with delivery mode or individual morbidities (Table 2). However, less maternal morbidity was observed in pregnancies with FGR after controlling for admission GA and dopplers (aOR 0.32, 95%CI:0.11-0.96).

Conclusion: Latency to delivery was similar between FGR and normally grown pregnancies with SPREX. FGR was associated with less maternal morbidity, suggesting differences in pathophysiology underlying early FGR in SPREX. Larger studies are needed to determine the association between latency and obstetric outcomes in SPREX.