Insulin Lispro in pregnancy - retrospective analysis of 33 cases and matched controls

Aims/hypothesis: To evaluate if the application of Lispro insulin in pregnancy increases the risk for malformations or unusual pregnancy courses. Methods: Diabetes specialists were contacted in Germany and Austria and asked to report women with diabetes who had been treated with Lispro during pregnancy. Furthermore they were asked to report another pregnant diabetic woman treated with regular insulin with similar HbA(1c) and age for each Lispro case. Following data were requested: age, first HbA(1c) in pregnancy and time of analysis, start and duration of Lispro treatment, ultrasound examination, chorionic villi biopsy, amniocentesis, unusual pregnancy courses, standard examination of the new-born for any malformation. Two-sided 95% confidence limits (95%-CI) for risk differences of proportions of malformations or unusual pregnancy courses were calculated. Results: 33 pregnant diabetic women with Lispro and 27 with regular insulin treatment were analysed (mean age 28.3 years (17-41)and 30.1 (19-40); mean HbA(1c) 6.9% (4.5-10.7) and 6.8% (4.7-9.8), respectively). There were four malformations or unusual pregnancy course (spontaneous abortion; elective interruption because of multiple malformations; heart malformations and hyaline membrane syndrom; premature birth) in the Lispro and one malformation (dyplastic hip) in the regular insulin group. Risk differences in proportions of malformation or unusual pregnancy courses were 8% (95%-CI: - 5% to 21%). Conclusions/interpretation: Risk differences for malformations or unusual pregnancy courses were not higher in the insulin Lispro group compared to the controls. However, we observed four malformations or unusual pregnancy courses in the Lispro group. A case-control study is suggested to get a precise risk estimate.