Routine first trimester combined screening for preterm preeclampsia in Australia : a multicenter clinical implementation cohort study

Objective: To assess pregnancy outcomes following first trimester combined screening for preterm preeclampsia in Australia. Methods: We compared pregnancy outcomes of women with singleton pregnancies who underwent first trimester combined preeclampsia screening with the Fetal Medicine Foundation algorithm between 2014 and 2017 in Melbourne and Sydney, Australia, with those from women who received standard care. The primary outcomes were preterm preeclampsia and screening performance. Effect estimates were presented as risk ratios with 95% confidence intervals. Results: A total of 29 618 women underwent combined screening and 301 566 women received standard care. Women who had combined screening were less likely to have preeclampsia, preterm birth, small neonates, and low Apgar scores than the general population. Women with high-risk results (≥1 in 100) were more likely to develop preterm preeclampsia (2.1% vs. 0.7%, risk ratio [RR] 3.04, 95% CI 2.46–3.77), while low-risk women (risk <1 in 100) had lower rates of preterm preeclampsia (0.2% vs. 0.7%, RR 0.26, 95% CI 0.19–0.35) and other pregnancy complications. Screening detected 65.2% (95% CI 56.4–73.2%) of all preterm preeclampsia cases, with improved performance after adjustment for treatment effect. Conclusions: First trimester screening for preeclampsia in clinical practice identified a population at high risk of adverse pregnancy outcomes and low-risk women who may be suitable for less intensive antenatal care. © 2021 International Federation of Gynecology and Obstetrics