Association of pregnancy outcomes in women with type 2 diabetes treated with metformin versus insulin when becoming pregnant

• Published in: BMC pregnancy and childbirth 2020-09, Vol.20 (1), p.512-8, Article 512
• Main Authors: Lin, Shu-Fu, Chang, Shang-Hung, Kuo, Chang-Fu, Lin, Wan-Ting, Chiou, Meng-Jiun, Huang, Yu-Tung
• Format: Article
• Language: English
• Subjects: Adult; Antidiabetics; Antihypertensives; Apgar score; Aspirin; Birth weight; Cesarean section; Datasets; Diabetes; Diabetes Mellitus, Type 2 - drug therapy; Female; Fetuses; Gestational age; Humans; Hypertension; Hypoglycemic Agents - adverse effects; Hypoglycemic Agents - therapeutic use; Infant, Newborn; Insulin; Insulin - adverse effects; Insulin - therapeutic use; Metformin; Metformin - adverse effects; Metformin - therapeutic use; Patients; Preeclampsia; Pregnancy; Pregnancy in Diabetics - drug therapy; Pregnancy Outcome; Premature birth; Retrospective Studies; Stillbirth; Womens health; Young Adult
• ISSN: 1471-2393; 1471-2393
• DOI: 10.1186/s12884-020-03207-0

Metformin use in pregnancy is controversial because metformin crosses the placenta and the safety on the fetus has not been well-established. This retrospective study aimed to compare pregnancy outcomes in women with preexisting type 2 diabetes receiving metformin or standard insulin treatment. The cohort of this population-based study includes women of age 20-44 years with preexisting type 2 diabetes and singleton pregnancies in Taiwan between 2003 and 2014. Subjects were classified into three mutually exclusive groups according to glucose-lowering treatments received before and after becoming pregnant: insulin group, switching group (metformin to insulin), and metformin group. A generalized estimating equation model adjusted for patient age, duration of type 2 diabetes, hypertension, hyperlipidemia, retinopathy, and aspirin use was used to estimate the adjusted odds ratio (aOR) and 95% confidence interval (CI) of adverse pregnancy outcomes. A total of 1166 pregnancies were identified in the insulin group (n = 222), the switching group (n = 318) and the metformin group (n = 626). The insulin group and the switching group had similar pregnancy outcomes for both the mother and fetus, including risk of primary cesarean section, pregnancy-related hypertension, preeclampsia, preterm birth (