Diabetic nephropathy and pregnancy: The effect of ACE inhibitors prior to pregnancy on fetomaternal outcome

Background. Diabetic nephropathy is associated with an increase in perinatal mortality and morbidity in uncontrolled pregnant patients. Recently angiotensin-converting enzyme inhibitor (ACE-I) was shown to improve the disease status in non-pregnant subjects. The purpose of this study was to examine the effect of prepregnancy treatment of insulin-dependent diabetes mellitus (IDDM) nephrotic women with captopril angiotensin converting enzyme inhibitor (ACE-I), on maternal renal function throughout pregnancy and on the fetomaternal outcome. Methods. Eight IDDM nephrotic patients planning pregnancy were treated with captopril for a minimum of 6 months prior to conception together with intensive insulin management. Conception was allowed when proteinuria was < 500 mg/day and euglycaemia was achieved. At conception captopril was discontinued. Results. At the beginning of captopril treatment, was 1633 +/- 666 mg/day. At conception, proteinuria dropped to 273 +/- 146 mg/day (P = 0.0000) and increased gradually over the three trimesters to 593 +/- 515, 783 +/- 813, and 1000 +/- 1185 mg/day respectively (P = 0.2 between the trimesters); declining to 619 +/- 411 mg/day (P = 0.0002 vs conception) 3 months after delivery. Only in two patients (25%) did proteinuria exceed 1000 mg/day during pregnancy. There was no significant change in any of the other renal function tests: CCT, serum creatinine, uric acid, K+ and blood pressure. However, there were three cases of PET just prior to delivery. Maternal glycaemic control improved significantly prior to conception (P = 0.002) and remained euglycaemic (reflected by daily glucose profile, HbA1C and fructosamine) throughout gestation. Perinatal outcome was excellent. Conclusion. Captopril treatment before pregnancy has a prolonged protective effect on maternal renal functions during pregnancy and results in a favourable maternal-fetal outcome.