Abstract
Background: Pathological insulin resistance in pregnancy is associated with an increased risk for complications such as gestational diabetes mellitus and pre-eclampsia. Individuals with pathological insulin resistance also exhibit hyperinsulinaemia. Currently, there are no diagnostic criteria for pathological hyperinsulinaemia in pregnancy that may be used to indicate risk of adverse outcomes.Aim: This case series aimed to explore the relationship between first trimester insulin response patterns and gestational outcomes.Setting: Auckland, New Zealand.Methods: Participants included four pregnant women with prepregnancy body mass index ≥ 25 kg/m2 and aged 25–35 years. Glucose and insulin response patterns were examined following a 120 min oral glucose tolerance test (OGTT) at 12–15 weeks of gestation using a modified Kraft methodology. Outcomes assessed at 25 and 35 weeks of gestation included gestational weight gain (GWG), blood pressure, fasting capillary blood glucose and foetal growth. Lifestyle and medical information were collected at each trimester. After delivery, total GWG, infant size, delivery method and clinical outcomes were recorded.Results: Kraft pattern IIB hyperinsulinaemia was identified in two cases. Amongst them, Case #1 experienced excessive GWG, induction of labour and surgically assisted delivery. Case #4 delivered by emergency caesarean, and the neonate required intensive care admission for 17 h. No cases developed hyperglycaemia or hypertension. Infant weights were between 3.75 kg and 3.86 kg.Conclusion: Dynamic insulin assay provides a promising template to assess metabolic risk in the first trimester of pregnancy. Diagnosing hyperinsulinaemia early in pregnancy means that lifestyle-based initiatives could be introduced earlier to mitigate excess GWG and potential adverse outcomes.