Nocturnal Insulin Requirements Are Higher in Pregnant Hispanic Women with Type 2 DM

T2DM is rapidly rising in pregnancy, especially in Hispanic women (HW). Classically, OBGYNs are taught to manage T2DM with a split dose NPH/Regular, especially if cost is a concern. OBGyn textbooks advise that 2/3 of total NPH be given in the am; 1/3 in pm based on historical data in Caucasians with T1DM. However, HW often display greater fasting glucoses (FBG) secondary to hepatic insulin resistance. We tested the hypothesis that more HW who are adequately controlled would require >50% of their NPH at night compared to non-Hispanic (NHW). All 667 pregnant women with T2DM at our county hospital from 2010-2016 were evaluated for inclusion (insulin treatment by 22 weeks, ≥5 prenatal visits, and ≥4/7 FBG≤95 mg/dl and A1C <6.5 by term). Our primary endpoint was tested with χ²; differences over time with generalized linear mixed-effects modeling. Inclusion criteria were met by 102 (81 HW and 21 NHW). Mean A1C decreased from baseline to term (7.7 to 5.9; 7.2 to 5.9 respectively). By term, more HW required >50% of NPH at night (51% vs. 19%, p=0.009). Fig. 1 shows at each prenatal visit, significantly more HW required >50% NPH at night (p< 0.05). Hispanic women require a higher % of NPH at night throughout gestation and at term to achieve adequate control. This novel finding questions the efficacy of traditional split dosing of NPH/Reg in HW and could lead to a change in dosing strategies and earlier FBG control, essential to improve outcomes.