LAUSR

BACKGROUND A definition of preeclampsia (PE) that incorporates assessment of maternal, fetal, and uteroplacental status optimizes identification of pregnancies at risk of complications at term gestational age. This includes 'carrying forward' angiogenic test results from 35-36 weeks to term gestational age. Would this approach still be useful if testing were performed earlier, at a routine mid-gestation scan, and the result used to inform the diagnosis of PE that developed thereafter? OBJECTIVE To evaluate whether fetoplacental assessment at a 19-23-week scan could be 'carried forward' to contribute to classification of PE and improve detection of women and babies at risk of adverse outcomes associated with hypertension. STUDY DESIGN In this prospective cohort study of singleton pregnancies at two maternity hospitals in England (Oct/2011 to Mar/2020), women attending a routine hospital visit at 19-23 weeks, underwent assessment that included history; ultrasonographic estimated fetal weight; Doppler measurements of the pulsatility index in uterine arteries; and serum placental growth factor (PlGF). PE was defined according to various definitions: (i) traditional, based on new-onset proteinuria at ≥20 weeks; (ii) American College of Obstetricians and Gynecologists (ACOG) 2013; (iii) International Society for the Study of Hypertension in Pregnancy 2018 maternal (ISSHP-M); (iv) ISSHP 2018 maternal plus fetal (death or growth restriction) (ISSHP-MF), by the 19+0-23+6 week scan, as estimated fetal weight (EFW) <3rd percentile or EFW at 3-10 percentile with a uterine artery pulsatility index (PI) >95th percentile; and (v) ISSHP 2021 maternal-fetal factors plus placental growth factor (ISSHP-MF+PlGF), with abnormal PlGF as <5th percentile for gestational age. Detection rates for outcomes of interest (i.e., severe maternal hypertension, major maternal morbidity, perinatal mortality or major neonatal morbidity, neonatal unit admission ≥48 hours, and birthweight <3rd percentile) ascertained by health record review were compared using chi-square. P<0.05 was considered statistically significant. RESULTS Among 40,241 singleton pregnancies, PE incidence varied by definition, from lows of 2.6% (traditional) and 3.0% (ACOG), to a high of 3.8% (ISSHP-MF+PlGF). The ISSHP-MF+PlGF definition (vs. the traditional) best-identified women who developed adverse outcomes: severe hypertension (detection rate of 70.6% vs. 52.8%; p<0.001); major maternal morbidity (100% vs. 87.5%, p=0.027); perinatal mortality or major morbidity (84.6% vs. 69.5%, p=0.004); neonatal unit admission for ≥48 hours (76.6% vs. 63.2%, p=.0002]; and birthweight <3rd percentile (81.3% vs. 61.9%, p<.0001]. Detection rates improved in going from ACOG to ISSHP-MF+PlGF definitions, for severe hypertension (11.4%, p=0.003), perinatal mortality or major morbidity (10.6%, p=0.03), neonatal unit admission for ≥48 hours (8.6%, p=0.01), and birthweight <3rd percentile (16.2%, p<0.001). However, in going from ISSHP-MF to ISSHP-MF+PlGF definitions, detection of babies with birthweight <3rd percentile improved (by 7.0%, p=0.01), but no other improvements were seen for: severe hypertension (1.7%, p=0.33), major maternal morbidity (0%), perinatal mortality or major morbidity (4.0%, p=0.20), and neonatal unit admission ≥48 hours (3.2%, p=0.17). CONCLUSION Criteria for uteroplacental dysfunction (including PlGF) from the 19-23 week assessment can be used in the assessment of women who are later suspected of having PE, to best identify pregnancies at risk of adverse outcomes.