Women with a predisposition for diabetes have an increased risk of pregnancy complications, especially in combination with pregestational overweight

BACKGROUND: Overweight and gestational diabetes are risk factors for pregnancy complications. We hypothesized that the metabolic impact of overweight on pregnancy outcome, would be different if it was combined with a predisposition for diabetes. The aim of this study was to compare the outcome of pregnancies in women with diabetes diagnosed later in life, to the outcome of pregnancies of women who did not develop diabetes. METHODS: Women in a population-based cohort who also were registered in the Swedish Medical Birth Registry (n = 4738) were included. A predisposition for diabetes (GDM or diabetes after pregnancy) was found in 455 pregnancies. The number of pregnancies with maternal BMI ≥ 25 kg/m2 and without diabetes were 2466, and in 10,405 pregnancies the mother had a BMI < 25 kg/m2 without diabetes at any time. Maternal BMI, gestational length, gestational weight gain, frequency of caesarean section, infant birth weight, frequency of large for gestational age (LGA) and Apgar score were retrospectively compared. RESULTS: Pregnancies with normal maternal BMI ≤25 kg/m2, with predisposition for diabetes had a higher frequency of LGA (11.6% vs. 2.9%; p < 0.001), a higher frequency of macrosomia (28.6% vs. 17.6%; p < 0.001), and a shorter gestational length (39.7 vs. 40 weeks; p = 0.08) when compared to pregnancies in women without a predisposition for diabetes. In addition, pregnancies with both maternal predisposition for diabetes and BMI ≥ 25 kg/m2 there was a higher frequency of LGA (23.3% vs. 7.1%; p < 0.001), caesarean section (24.0% vs. 14.9%, p = 0.031) compared to pregnancies in women who were only overweight. A predisposition for diabetes significantly increases the risk of macrosomia (OR1.5; 95% CI 1.07-2.15; p = 0.02). CONCLUSIONS: In pregnancy, there is an increased frequency of LGA, macrosomia and caesarean section if the woman has a predisposition for diabetes. The frequency of overweight young women is increasing, and it is urgent to identify pregnant women with a predisposition to diabetes. How to distinguish the women with the highest risk for adverse pregnancy outcome and the highest risk of future disease, remains to be studied.