Risk of preterm birth with routine first-trimester combined screening for pre-eclampsia

Preterm birth (PTB) is a major public health problem worldwide. It can occur spontaneously or be medically indicated for obstetric complications, such as pre-eclampsia (PE) or fetal growth restriction. The main objective of the study was to investigate the implication of uteroplacental dysfunction in the first trimester in subsequent PTB. This retrospective cohort study on singleton pregnancies was conducted between March 2018 and December 2020. A total of 11,437 women underwent first-trimester screening for preterm PE using the Fetal Medicine Foundation algorithm, which includes maternal factors, mean arterial pressure (MAP), uterine artery pulsatility index (UtA-PI) and pregnancy-associated plasma protein (PAPP-A). Women with a risk of ≥1 in 50 for preterm PE were classified as high-risk and offered prophylactic aspirin 150mg and serial ultrasound assessments. The following outcomes at delivery were collected: PTB, iatrogenic PTB (iPTB) and spontaneous PTB (sPTB). 475 (4.2%) women had preterm births with 308 (64.8%) sPTB and 167 (35.2%) iPTB. Patients with PTB had a higher body mass index, were more likely to be Black or Asian and have a history of previous PTB. They also had higher MAP (87.70 vs 86.00, p