(706) Trends in postpartum sFLt-1 among patients diagnosed with preeclampsia with severe features

Friday, January 31, 2025

10:30 AM – 12:30 PM

Submitting Author and Presenting Author(s)

Ashten B. Waks, MD, MSPH (she/her/hers)

Maternal-Fetal Medicine Fellow
University of California Irvine
Orange, California, United States

Coauthor(s)

Devesh Naidoo, MD

Fellow
MemorialCare Miller Children's and Women's Hospital Long Beach University of California Irvine
Long Beach, CA, United States
DC

Dongbao Chen, PhD

University of California Irvine
Orange, California, United States
Megan C. Oakes, MD, MSCI (she/her/hers)

Maternal-Fetal Medicine
MemorialCare Miller Children's and Women's Hospital Long Beach
Long Beach , CA, United States

Objective: Because an excess of anti-angiogenic proteins like soluble fms-like tyrosine kinase 1 (sFlt-1) relative to pro-angiogenic proteins is thought to result in preeclampsia, placental delivery is regarded as curative for this condition. As there is little research on the impact of delivery on such placental proteins, this study sought to examine postpartum trends in sFlt-1 among patients with preeclampsia.

Study Design: A prospective pilot study of pregnant persons without chronic hypertension delivered for preeclampsia with severe features between 7/2023 – 6/2024. Subjects had at least 2 postpartum sFlt-1 levels drawn, the first within 24 hours of delivery and the second within 10 days of delivery. Primary outcome measures included change in sFlt-1 over time and postpartum half-life of sFlt-1. The normality of distribution for these continuous outcomes was tested by Kolmogorov-Smirnov test, and outcomes with normal distributions were presented as means while those with non-normal distributions were presented as medians. Half-life was calculated according to first-order elimination principles.

Results: Among 20 subjects with preeclampsia with severe features, 16 (80%) had at least 2 postpartum sFlt-1 levels drawn. Median sFlt-1 was 9,304pg/mL (IQR 7,060 – 25,051pg/mL) and 508pg/mL (IQR 402 – 855pg/mL) on postpartum day 1 and 7, respectively. This translated to a median reduction in sFlt-1 of 8,800 pg/mL (IQR 7,076 – 24,650pg/mL) and a median half-life of only 1.51 days (IQR 1.13 – 1.73 days). These trends did not vary when assessed according to variables including maternal age, ethnicity, body mass index, medical comorbidities, antenatal aspirin exposure, gestational age at diagnosis, blood pressure at delivery, or need for antihypertensives postpartum (p > 0.32).

Conclusion: Even in patients with preeclampsia with severe features, serum sFlt-1 levels declined rapidly over the first week postpartum. This suggests that factors other than clearance of abnormal placental proteins are likely responsible for persistent postpartum hypertensive disease.