The Impact of Small for Gestational Age Births in Early and Late Preeclamptic Pregnancies for Preeclampsia Recurrence: a Cohort Study of Successive Pregnancies in Sweden.

BACKGROUND

Results from uterine artery Doppler investigations suggest that the aetiology of late preeclampsia with fetal growth restriction may be more similar to the aetiology of early preeclampsia than with late preeclampsia without fetal growth restriction. We hypothesised that a small-for-gestational-age (SGA) birth in a late preeclamptic pregnancy may be associated with increased subsequent risk of early preeclampsia. We also studied effects of maternal factors on risks of preeclampsia recurrence.

METHODS

In a nation-wide Swedish cohort study of first and second consecutive single births between 1992 and 2012, we identified 22 473 mothers with preeclampsia in their first pregnancy. We calculated relative risks (RR), and 95% confidence intervals (CI), to investigate associations between subtypes of preeclampsia in the first pregnancy and risks of early (<34 weeks) and late (≥34 weeks) preeclampsia in the second pregnancy.

RESULTS

In women with a previous late preeclampsia, a co-occurring SGA birth was associated with an increased risk of subsequent early preeclampsia (adjusted RR 2.85, 95% CI 1.93, 4.20), but not of subsequent late preeclampsia. Among women with a previous early preeclampsia, a co-occurring SGA birth was not associated with increased subsequent risks of early or late preeclampsia. Interpregnancy weight gain was associated with increased risks of early and late preeclampsia in the second pregnancy.

CONCLUSIONS

Late preeclampsia combined with fetal growth restriction may be regarded as an ischaemic placental disease. Given the high absolute risk of preeclampsia recurrence, preventing weight gain may be especially important in women with previous preeclampsia.