To examine the impact of nephrotic range proteinuria during pregnancy on renal, maternal and fetal outcomes.

A retrospective study of pregnant women with proteinuria greater than 3 g/24 h. Outcome measures included: gestation and mode of delivery, maternal high dependency unit admission, birth weight, maternal blood pressure and proteinuria at time of last follow-up, renal biopsy.

Two hundred and sixty four pregnancies in 262 women were reviewed. Postnatal data were available in 180; of these 104 (57%) had urinary protein quantified postnatally. Sixty three (60%) were pure preeclampsia and nine (9%) super-imposed preeclampsia. Biopsy-proven renal disease was newly diagnosed in nine (9%). Sixty three per cent required caesarean section and 34% required high dependency unit admission. There were no maternal deaths. Birth weight corrected for gestation was below the fifth centile in 33%.

The incidence of underlying renal pathology in this cohort is significant and highlights the importance of careful follow-up.