GLP-1 receptor agonists around conception: no pooled signal for maternal complications

Design

Systematic review and meta-analysis, random effects with Knapp-Hartung adjustment, of cohort, case-control and randomised crossover studies

Population

186,598 pregnancies from eight studies, 47,159 exposed to a GLP-1 receptor agonist before or in early gestation

Primary outcome

Gestational diabetes, preterm birth, pre-eclampsia and hypertensive disorders of pregnancy

Effect

Preterm birth OR 1.01 (95% CI 0.76 to 1.33); pre-eclampsia OR 1.05 (0.60 to 1.84); gestational diabetes OR 0.99 (0.61 to 1.61)

Investigators pooled eight studies covering 186,598 pregnancies, 47,159 of them exposed to a GLP-1 receptor agonist before or in early gestation. Pooled odds ratios were close to one for gestational diabetes (0.99, 95% CI 0.61 to 1.61), preterm birth (1.01, 0.76 to 1.33), pre-eclampsia (1.05, 0.60 to 1.84) and hypertensive disorders of pregnancy (0.79, 0.34 to 1.83).

The quality of the contributing studies varied, and heterogeneity was high because exposure and outcome definitions, cohort selection and confounder control differed. Dropping one study at a time, the authors saw a lower odds of gestational diabetes (0.81, 0.67 to 0.98). They describe that as hypothesis-generating.

For a woman who conceives while on one of these drugs, the data do not point to a maternal complication that should prompt alarm. They also do not settle fetal safety or the right time to stop the drug, which this analysis did not address. Weight and glycaemic plans should be agreed before conception where possible.

• Pooled odds ratios for preterm birth, pre-eclampsia and gestational diabetes were all close to 1.
• Exposure was around conception; the analysis does not cover use through the whole pregnancy.
• Eight studies with mixed quality and high heterogeneity: treat the result as reassuring, not conclusive.
• A possible lower gestational diabetes risk appeared only in a sensitivity analysis.
• Women who conceive on a GLP-1 drug still need a clear plan for stopping it and for glycaemic follow-up.

Why it matters

It lowers the worry about maternal complications for the many women who conceive unexpectedly on these drugs.

Don't overread it

Observational pooling cannot show safety for the fetus, and the lower gestational diabetes signal is exploratory.

The statistics, in plain English

An odds ratio of 1 means no difference between exposed and unexposed pregnancies. Every confidence interval here crosses 1, so the data are compatible with no effect, a modest benefit or a modest harm; the wide intervals for pre-eclampsia and hypertensive disorders leave real room for either. The lower gestational diabetes estimate appeared only after removing studies one at a time, which makes it a weaker finding than the headline result. High heterogeneity means the studies did not agree on definitions or populations, so a single pooled number hides real differences.

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