- Design
- Systematic review and meta-analysis of observational cohorts
- Population
- 669 SGLT2 inhibitor-exposed pregnancies in women with type 2 diabetes, three cohorts
- Primary outcome
- Major congenital malformations
- Effect
- RR 0.94 (95% CI 0.68 to 1.29) versus insulin comparator
A systematic review pooled three observational cohorts comparing early-pregnancy or preconception exposure to SGLT2 inhibitors with other glucose-lowering drugs in women with type 2 diabetes. There were 669 exposed pregnancies in total.
Against insulin, the prespecified comparator, exposure was not associated with 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 overall estimate. One Korean cohort, however, found exposure during gestational weeks 4 to 10 associated with congenital heart defects (RR 2.79, 1.16 to 7.06).
The authors graded certainty as low to very low. Confounding by the indication for each drug, the restriction to live births, and very few exposed events all limit what can be concluded. The intervals are wide enough to include a clinically important increase in risk.
In practice this is reassurance for counselling after inadvertent exposure, not permission to continue the drug once pregnancy is planned or known. More women of reproductive age now take these drugs for kidney and heart protection as well as diabetes, so the conversation will come up more often.
- Ask every woman of reproductive age on an SGLT2 inhibitor about pregnancy plans and contraception.
- After inadvertent first-trimester exposure, explain that three cohorts did not show a clear overall rise in major malformations.
- Be honest that the evidence is limited and a possible cardiac signal with exposure in weeks 4 to 10 has not been excluded.
- Consider offering a detailed fetal cardiac scan where exposure fell in early organogenesis.
- Switch to a drug with established pregnancy data, usually insulin, once pregnancy is confirmed or planned.
Why it matters
These drugs are increasingly prescribed to young women for kidney and heart protection, so unplanned first-trimester exposure is becoming a routine counselling question.
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
A risk ratio of 0.94 means roughly the same risk in exposed and unexposed pregnancies. But the interval runs from 0.68 to 1.29, so the data are compatible with up to about 29% more malformations. The cardiac signal comes from one cohort and a subgroup defined by timing, which makes it weaker than the overall result, though it cannot be dismissed.
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