The effect of pregnancy on mild diabetic retinopathy

To study microaneurysm (MA) formation and disappearance rates during pregnancy and postpartum in diabetic women with mild diabetic retinopathy.

Red-free photographs were taken at the 12th, 24th and 32nd-36th weeks of pregnancy and 3 and 6 months postpartum from 21 type 1 diabetics with mild diabetic retinopathy. In a subset of 13 patients follow-up was continued until 1 year after pregnancy. Fundus photographs were analysed using a computer-assisted fundus lesion localization system.

In the whole material the total MA count was 3.1 +/- 3.6 (mean +/- SD) at the 12th week, 3.4 +/- 3.1 at the 24th week, 4.1 +/- 4.9 at the 32nd-36th week, 5.4 +/- 6.2 at 3 months postpartum and 5.2 +/- 5.8 at 6 months postpartum. We found that MA count increased during pregnancy, but it was highest 3 months postpartum. Both the rate of MA formation and the rate of MA disappearance increased during pregnancy, with the disappearance rate exceeding the formation rate 6 months postpartum. In patients having mean HbA1c levels below the median value of 6.38 mmol/l there was a flare-up of MAs during pregnancy, levelling by 3 months postpartum. Patients with a higher than the median (0.76 mmol/l) decrease in HbA1c level compared to pre-pregnancy HbA1c also developed more MAs during the course of pregnancy.

These data suggest that there is continuous turnover of MAs during pregnancy. MA count increases during pregnancy but the MA count was highest 3 months postpartum, after which the formation rate started to decline. Temporary aggravation of mild retinopathy occurs in diabetic patients after normalization of blood glucose levels.