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TOPLINE:

Among parous women, an additional pregnancy was associated with an isolated decline in whole-body insulin sensitivity over 10 years, with no corresponding changes in the measures of beta‑cell function and glycemia.

METHODOLOGY:

• Pregnancy causes marked changes in insulin sensitivity and beta‑cell function that largely resolve after delivery but may leave subtle long‑term effects that increase future diabetes risk.
• Researchers conducted a prospective cohort study of 303 parous women to compare 10-year trajectories of insulin sensitivity, beta-cell function, and glycemia between those who did and did not have an additional pregnancy.
• All women were assessed at 1 year post-partum and at least three additional times over the subsequent decade; 78 had an additional pregnancy (mean age, 34.9 years) and 225 did not (mean age, 38.0 years).
• The median time between baseline and delivery of the first additional pregnancy was 2.5 years.
• Each visit comprised a physical exam and a 2-hour, 75-g oral glucose-tolerance test, with glucose and insulin measured at fasting and at 30, 60, and 120 minutes post-challenge; these measurements were used to evaluate whole-body insulin sensitivity, hepatic insulin resistance, and beta-cell function.

TAKEAWAY:

• Women who did vs did not have an additional pregnancy had higher whole-body insulin sensitivity at baseline (estimated adjusted average difference, 1.64; P = .02), but this difference attenuated and subsequently disappeared at 3.5 and 5.5 years.
• The 10-year trajectory of whole-body insulin sensitivity differed between the groups (P for the time-group interaction = .02); sensitivity was initially higher in women who had an additional pregnancy and subsequently converged with that of the other group over the latter two thirds of the decade.
• No between-group differences were observed in the trajectories of hepatic insulin resistance, beta-cell function, or blood glucose at fasting and at 30, 60, and 120 minutes post-challenge.
• Among women with normal glucose tolerance at baseline, having an additional pregnancy was not associated with progression to dysglycemia.

IN PRACTICE:

“Given the capacity to improve insulin sensitivity with weight loss, these findings further support current interest in targeting postpartum care as a unique clinical opportunity for improving the long-term health of women, with reduction in their future risk of diabetes emerging as a potentially achievable beneficial effect of such efforts,” the authors wrote.

SOURCE:

The study was led by Ravi Retnakaran, MD, Mount Sinai Hospital, Toronto, Ontario, Canada. It was published online in Diabetes Care.

LIMITATIONS:

Because this was an observational study, it could not establish causality — whether an additional pregnancy itself led to changes in insulin sensitivity. The researchers used oral glucose tolerance test-based measures rather than clamp tests to assess insulin sensitivity and beta-cell function. They did not adjust for socioeconomic status or education, which could have affected access to care and lifestyle behaviors.

DISCLOSURES:

The study was supported by the Canadian Institutes of Health Research. The authors disclosed having no relevant conflicts of interest.

This article was created using several editorial tools, including AI, as part of the process. Human editors reviewed this content before publication.