Pregnancy in women with renal disease may be detrimental to maternal renal function and increases the risk of obstetric complications such as pre-eclampsia and intrauterine growth restriction. Women with a preconception glomerular filtration rate of less than 30ml/min (serum creatinine >170μmol/l) have a one in three chance of an accelerated decline in renal function and are likely to have small or premature babies. Pre-existing hypertension, proteinuria and recurrent urinary tract infections (and poor glycaemic control in women with diabetic nephropathy) are all independently but cumulatively detrimental to maternal and fetal outcome. Women with end-stage renal failure are far more likely to have a successful pregnancy following a kidney transplant compared with those on dialysis. Peripartum fluid balance is especially important for women with renal impairment. Intravascular volume is difficult to assess clinically during pregnancy; therefore, in the presence of renal impairment, invasive monitoring (central venous pressure or pulmonary artery catheter) is usually necessary. Immediately after a healthy delivery, urine output may transiently fall to less than 100ml/4h. Injudicious fluid replacement readily leads to pulmonary oedema, a major cause of maternal death.