Abnormal uterine artery Doppler in small-for-gestational-age pregnancies is associated with later hypertension

In a cohort of normotensive small-for-gestational-age (SGA) pregnancies, we aimed to determine the prevalence of later preeclampsia and gestational hypertension. We hypothesised that (i) uterine artery Doppler abnormalities would increase in severity from those with normotension to gestational hypertension to preeclampsia and (ii) the severity of uterine artery Doppler abnormalities would be related to the severity of fetal disease. Serial uterine and umbilical artery Doppler studies were performed on 224 normotensive women with SGA pregnancies, from detection of SGA until delivery. Outcomes were compared between groups that remained normotensive (n = 174) and those that developed gestational hypertension and preeclampsia. Of the women studied, 50 (22%) subsequently developed hypertension [(3% (n = 8) preeclampsia, 19% (n = 42) gestational hypertension)] at a median (interquartile range) of 19 (12-32) days after recognition of SGA. Mean uterine artery resistance indices (RI) increased from women who remained normotensive (n = 174) to those who later developed gestational hypertension or preeclampsia [0.51 (SD 0.09), 0.55 (0.09), 0.62 (0.13), p < 0.001], as did the proportion of abnormal uterine RI (33%, 39%, 88%, p = 0.007) and umbilical RI (28%, 40%, 75% p = 0.007). Mean uterine RI correlated negatively with z score birthweight (R2 = 0.069, p < 0.001) and positively with umbilical RI (R2 = 0.16, p < 0.001).