Is mid-gestational uterine artery Doppler still useful in a setting with routine first-trimester pre-eclampsia screening? A cohort study.

Objective: To evaluate whether routine mid-gestational uterine artery Doppler (UtAD) modifies the risk for preterm pre-eclampsia after first-trimester combined pre-eclampsia screening.

Design: Retrospective cohort study.

Setting: London Tertiary Hospital.

Population: A cohort of 7793 women with singleton pregnancies, first-trimester pre-eclampsia screening using the Fetal Medicine Foundation (FMF) algorithm and UtAD pulsatility index (PI) assessment at the mid-gestation ultrasound.

Methods: Pregnancies were divided into four groups: high risk in both trimesters (H H ), high risk in the first but not in the second trimester (H L ), low risk in the first but high risk in the second trimester (L H ) and low risk in both trimesters (L L ).

Main Outcome Measures: Small for gestational age (SGA), hypertensive disorders of pregnancy (HDP) and stillbirth.

Results: In this cohort, 600 (7.7%) and 620 (7.9%) women were designated as being at high risk in the first and second trimesters, respectively. Preterm pre-eclampsia was more prevalent in the H L group (4.5%) than in women considered at low risk in the first trimester (0.4%, p < 0.0001). The prevalence of preterm pre-eclampsia in the L H group (3.3%) was significantly lower than that in women considered at high risk in the first trimester (7.0%, p = 0.0076), and was higher than that observed in the L L group (0.2%, p < 0.0001). The prevalence of SGA and term HDP followed similar trends.

Conclusions: Pre-eclampsia risk after first-trimester FMF pre-eclampsia screening may be stratified through mid-gestational routine UtAD assessment. Pregnancy care should not be de-escalated for low mid-gestational UtAD resistance in women classified as being at high risk in the first trimester. The escalation of care may be justified in women at low risk but with high mid-gestational UtAD resistance.