Heritability of GDM
GDM is thought to have strong heritability. GDM women have an increased positive family history of T2DM. Compared to pregnant women with normal glucose tolerance, GDM women have a significantly greater parental history of T2DM (13.2% vs. 30.1%, p < 0.001) [10]. In addition, both GDM women and their offspring are at increased risk of future development of T2DM. The heritability estimate of T2DM was reported to be quite high (h2 = 0.69) in a recent study performed in Europeans [11]. These findings are indirect evidence that GDM has familial tendency. However, there is no study that has specifically evaluated the heritability of GDM using familial clustering or twins [12]. It would be important to estimate the heritability of GDM and compare it with that of T2DM in women.