- Design
- Systematic review and meta-analysis of 3 observational cohorts
- Population
- Women with type 2 diabetes; 669 SGLT2 inhibitor-exposed pregnancies
- Primary outcome
- Major congenital malformations vs active comparators
- Effect
- RR 0.94 (95% CI 0.68–1.29) vs insulin; cardiac RR 0.97 (0.64–1.48)
SGLT2 inhibitors are now prescribed to many women of reproductive age, for diabetes and for heart and kidney protection, and are often continued until a pregnancy is recognised. This meta-analysis pooled three observational cohorts comparing early exposure with other glucose-lowering drugs, covering 669 exposed pregnancies.
Against insulin, early exposure was not associated with more major congenital malformations (RR 0.94, 95% CI 0.68 to 1.29) or cardiac malformations (RR 0.97, 0.64 to 1.48). Adding a sulfonylurea-comparator cohort gave a similar result. But one Korean cohort found exposure in gestational weeks 4–10 was associated with congenital heart defects (RR 2.79, 1.16 to 7.06).
The authors rate certainty as low to very low: few exposed events, residual confounding, counting only live births, and varied exposure definitions. The confidence intervals cannot exclude a clinically important increase. The reassurance is for the woman already exposed; it is not a licence to continue the drug in pregnancy, which product labels advise against.
The practical change is in counselling. A woman who conceives on an SGLT2 inhibitor can be given a measured, non-alarming account, switched promptly, and offered detailed fetal anomaly and cardiac scanning.
- Ask about pregnancy plans when prescribing an SGLT2 inhibitor to a woman of reproductive age.
- Discuss contraception or a planned switch before conception, since labels advise against use in pregnancy.
- Stop the SGLT2 inhibitor promptly once pregnancy is confirmed and move to insulin-based care.
- Offer an inadvertently exposed woman balanced counselling: overall malformation risk was not raised in pooled data.
- Consider a detailed fetal cardiac scan after exposure in weeks 4–10, given the single-cohort signal.
Why it matters
Early exposure is now common, and until now clinicians had little human data to counsel from.
Don't overread it
Low-certainty observational data with wide intervals cannot show that SGLT2 inhibitors are safe in pregnancy.
The statistics, in plain English
An RR of 0.94 suggests no difference, but the interval runs from a 32% lower to a 29% higher risk, so a meaningful increase is not excluded. The cardiac signal (RR 2.79) comes from one cohort and one exposure window; a subgroup like this is weaker than the pooled estimate and needs replication.
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