(950) What to Expect of Expectant Management in Preterm Preeclampsia with Severe Features

Objective: Despite common practice in the US, Level I data from RCT’s of expectant management of preterm preeclampsia with severe features (PSF) is limited. Of the three RCT’s conducted, only one was performed in the US 30 years ago. There is also limited evidence guiding management in the setting of fetal growth restriction (FGR). Our objective was to describe maternal and perinatal outcomes with expectant management of early onset PSF by gestational age (GA) at diagnosis and by presence of FGR.

Study Design: This is a retrospective cohort study of pregnant individuals with a diagnosis of PSF between 24-34 weeks at a single Level 4 center between January 2022 to April 2024. Exclusion criteria was delivery < 24 hours of admission. We compared the latency period (time interval from diagnosis to delivery) by GA at diagnosis and presence or absence of FGR. Indications for delivery, maternal and perinatal outcomes were evaluated.

Results: Over the study period, 241 patients were admitted with PSF < 34 weeks and 73% (n=175) met criteria for analysis. Patients were divided by GA: 24w0d–27w6d (n=43), 28w0d–31w6d (n=90), and 32w0d–33w-6d (n=42). There were no significant differences in maternal characteristics.

Latency was longer with earlier GA at PSF diagnosis. The median (IQR) latency in days was 6.4 (2.7–14.2) in group 1, 4.2 (2.5-11.0) in group 2, and 3.0 (1.7-6.4) in group 3 (p=0.024).

Rate of FGR was significantly higher with earlier onset at 51%, 46%, and 21% in groups 1, 2, and 3 (p=0.01) and was associated with decreased latency though it did not reach statistical significance (Figure 1). Latency when PSF is diagnosed beyond 32 weeks in the presence of FGR was only 1.7 days (1.5 – 7.6). Fetal indications for delivery were higher in group 1 (65 vs 47, and 24%, p= 0.002) (Table 1).

Conclusion: In pregnancies complicated by preterm PSF, latency decreased with advancing gestational age at diagnosis especially in the setting of FGR. Further studies are needed to evaluate if there is a benefit in attempting expectant management beyond administration of corticosteroids when PSF is diagnosed beyond 32 weeks with FGR.