Oral antidiabetic use during pregnancy not associated with adverse birth outcomes
medwireNews: Women with diabetes who use oral antidiabetic agents during the first trimester of pregnancy do not have a greater risk for adverse maternal or fetal outcomes than those using insulin, researchers report.
Lucía Cea-Soriano (Spanish Centre for Pharmacoepidemiologic Research, Madrid, Spain) and study co-authors analyzed data from 1511 women with pre-gestational diabetes who were registered in The Health Improvement Network (THIN) database. Over half (60%) of participants had type 1 diabetes, and 40% had type 2 disease.
A total of 311 participants received treatment with oral antidiabetic agents (with or without insulin) during the first trimester of pregnancy, 95% of whom were taking metformin, while 883 patients were treated with insulin alone and the remaining 317 women had no recorded medication.
In all, 21.9% of participants who were treated with oral antidiabetic agents suffered a miscarriage, compared with 13.3% of those in the insulin group, giving an unadjusted odds ratio (OR) of 1.83. However, the difference was no longer statistically significant after adjustment for age, hyperlipidemia, BMI, pre-pregnancy glycemic control, and diabetes type.
Moreover, there was no significant difference in the rate of births with major malformations between women in the oral antidiabetic and insulin groups (2.6 vs 9.6%), and the researchers note that the numbers of stillbirths “were small and the OR estimates imprecise.”
Noninsulin antidiabetic agents “did not present an increased risk” for adverse birth outcomes relative to insulin, summarize Cea-Soriano and colleagues.
The team also identified an association between diabetes type and pregnancy outcomes. Relative to those with type 2 diabetes, women with type 1 disease were significantly less likely to experience miscarriage (adjusted OR=0.68), but more than three times more likely to have infants with major malformations (adjusted OR=3.21).
These results “suggest different adverse pregnancy outcomes for women with pre-gestational [type 1 diabetes] and those with pre-gestational [type 2 diabetes],” write the researchers in Diabetes, Obesity and Metabolism.
They suggest that differences in the placenta between women with different forms of diabetes may explain the greater risk for pregnancy loss in those with type 2 diabetes, whereas the association between type 1 diabetes and malformations “may reflect the effect of [type 1 disease] and the poor glycaemic control in these women.”
In support of this theory, the team found that women with pre-pregnancy glycated hemoglobin (HbA1c) levels above 7% were significantly more likely to deliver infants with major malformations than those with lower HbA1c levels, “highlighting the importance of improving diabetes control in women of childbearing age before they enter the first trimester.”
Cea-Soriano and colleagues note that their findings on oral antidiabetic agents were mainly based on metformin, and highlight a “limited amount, or absence, of data available concerning the safety of glitazones, meglitinides, alpha-glucosidase inhibitors, dipeptidyl peptidase-4 inhibitors, or newer antidiabetic therapies during pregnancy.”
And they conclude: “Further evidence concerning the safety of non-insulin antidiabetics other than metformin in pregnant women with [type 2 diabetes] is needed.”
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