Managing diabetes in pregnancy remains a challenge, but new research offers important guidance. A systematic review published in eClinicalMedicine examined 17 studies involving thousands of pregnant individuals with preexisting type 1 or type 2 diabetes.

In one of the trials, the combination of metformin and insulin therapy was tested. In two large studies involving over 1100 patients, this combination reduced the risk of large-for-gestational-age (LGA) infants. The combination was tested against insulin alone for this common complication in infants. However, results for other outcomes such as preeclampsia and neonatal intensive care admissions were mixed, with one smaller study suggesting fewer NICU admissions when metformin was added.

Another major focus was on glucose monitoring technologies. Evidence from three randomized trials and one cohort study showed that continuous glucose monitoring (CGM) improved perinatal outcomes in some populations, including lower odds of neonatal complications (adjusted OR 0.48; 95% CI 0.24-0.94). hybrid closed-loop (HCL) insulin pumps, which automatically adjust insulin based on glucose readings, were tested in five trials. While results showed no consistent improvement in time-in-range, individual studies suggested reductions in neonatal risks.

The review also assessed newer drugs such as GLP-1 receptor agonists, but only limited observational evidence was available, with no clear increase in congenital malformations compared with insulin use.
While insulin remains the standard of care, adjunctive therapies like metformin, CGM, and automated insulin pumps are showing early promise. Large-scale, detailed trials are needed to confirm benefits and inform future guidelines.