Pre-eclampsia and pregnancy-induced hypertension are associated with severe diabetic retinopathy in type 1 diabetes later in life

To investigate whether pre-eclampsia (PE) or pregnancy-induced hypertension (PIH) predicts the development of severe diabetic retinopathy (SDR) in type 1 diabetes. Altogether, 203 women with type 1 diabetes who were followed during pregnancy were re-examined within the Finnish Diabetic Nephropathy Study. After excluding patients with pre-pregnancy hypertension and those who had had laser treatment or whose retinopathy was graded as proliferative at the index pregnancy, 158 were prospectively studied. As a surrogate marker for SDR, retinal laser photocoagulation was used. The time from pregnancy to SDR (N = 21) or follow-up was 16 years (interquartile range, 11–19). HbA_1c was repeatedly measured both during pregnancy and follow-up. Women with prior PE (26 % vs. 6 %, P = 0.003) or PIH (24 % vs. 6 %, P = 0.008) had more often incident SDR during follow-up compared to those with normotensive pregnancy. The hazard ratios (HR) remained associated with the progression to SDR after adjustment for duration of diabetes and diabetic nephropathy in a Cox regression analysis [PE: 3.5 (95 % CI 1.1–10.9); P = 0.03 and for PIH: 3.2 (1.1–9.8); P = 0.04]. The association between PIH and incident SDR did not change after inclusion of mean HbA_1c, measured during pregnancy (all 3 trimesters) and serial HbA_1c measurements during follow-up, 3.5 (1.1–11.8; P = 0.03). However, in a similar model, the HR for PE was no more significant 2.0 (0.6–6.8; P = NS). The results suggest that women with type 1 diabetes and a hypertensive pregnancy have an increased risk of severe diabetic retinopathy later in life.