History of Spontaneous Abortion Linked to Increased Risk of Gestational Diabetes

Results of a retrospective cohort study of more than 100,000 pregnant women suggest a history of spontaneous or induced abortion was associated with a subsequent increase in risk of developing gestational diabetes.

An analysis of data from 102,259 pregnant women receiving care at a tertiary hospital in Shanghai, results suggest women with a history of spontaneous abortion were at an 18% greater risk of gestational diabetes, but no increased risk was observed for history of induced abortion. Investigators purport the results underline the need for increased monitoring and prevention strategies among women with a history of abortion.

“Our findings suggest that pregnant women with a history of spontaneous abortion, especially those with a history of recurrent spontaneous abortion, should attend more antenatal visits to monitor their blood glucose and implement early prevention and intervention,” investigators wrote. “Considering the short- and long-term adverse effects of gestational diabetes on both mothers and their offspring, our findings may also have potential public health implications.”

With the burden of gestational diabetes continuing to balloon and previous studies linking spontaneous abortion and induced abortion to increased risk of metabolic disease, investigators from the School of Medicine at Tongji University sought to assess whether spontaneous or induced abortion, as a composite and individually, were associated with increased risk of gestational diabetes. With this in mind, investigators designed a retrospective cohort study of pregnant women who registered in the outpatient clinics of the department of obstetrics at a tertiary hospital in Shanghai, China and visited the clinic regularly from January 2014-December 2019.

A total of 125,430 registered women were identified from the investigators’ initial query. Of these, 102,259 were included in the final analytical cohort, which included 65,728 with no abortion history, 14,579 with spontaneous abortion experience only, 17,935 with induced abortion experience only, and 4017 with both spontaneous abortion and induced abortion experience. Overall, 12,153 cases of gestational diabetes were identified, with a prevalence rate of 11.9%.

The mean age of the overall study cohort was 29.8 (SD, 3.8) years. Compared to their counterparts without a history of abortion, those with abortion history were more likely to be multiparous, more likely to have obesity, and the proportion of pregnant women older than 35 years was more than 2-fold greater among pregnant women with abortion history than those with no abortion history.

The primary outcome of interest was a diagnosis of gestational diabetes, which was screened for and diagnosed at 24-28 weeks of gestation using a 75-g diagnostic oral glucose tolerance test. Investigators planned to use a multivariable-adjusted log-binomial analysis to estimate relative risk of gestational diabetes associated with history of abortion.

Upon analysis, investigators found women who experienced only spontaneous abortion (RR, 1.25 [95% CI, 1.18-1.31]) or both spontaneous abortion and induced abortion (RR, 1.15 [955 CI, 1.05-1.27]) were at an elevated risk for development of gestational diabetes. Further analysis indicated the association between history of spontaneous abortion and gestational diabetes appeared to occur in a number-dependent manner. Specifically, compared to their counterparts with no history of abortion, a single spontaneous abortion was associated with an 18% greater relative risk of gestational diabetes (Rr, 1.18 [95% CI, 1.11-1.26]), 2 spontaneous abortions were associated with a 41% increase (RR, 1.41 [95% CI, 1.27-1.57]), and more than 2 spontaneous abortions was associated with a 43% increase in risk (RR, 1.43 [95% CI, 1.22-1.67]). Investigators noted no associations were observed for history of induced abortion only with increased risk of gestational diabetes.

Investigators pointed out multiple limitations hinder the applicability of study results to clinical practice. These limitations included reliance on self-reported data for spontaneous abortion history, reliance on data from pregnant women in China, and potential for residual confounding from unmeasured or unknown confounders.

This study, “Association of History of Spontaneous or Induced Abortion With Subsequent Risk of Gestational Diabetes,” was published in JAMA Network Open.