In a population-based cohort study that included more than 1.2 million hospital live births, PCOS was associated with a 5% increase in risk for gestational diabetes. Almost 90% of this association was mediated by obesity.
“Women with PCOS are at higher risk, but it’s only 5% higher than the general population. However, that risk rises substantially with obesity,” senior author Maria P. Velez, MD, PhD, clinician-scientist and associate professor of obstetrics and gynecology at Queen’s University, Kingston, Ont., said in an interview. “Our study highlights the need for counseling our patients about the importance of weight optimization, ideally starting with lifestyle changes like diet and exercise.”The findings were published in the Journal of Obstetrics and Gynaecology Canada.
Major mediator
The estimated prevalence of PCOS is 8%-13%, and affected patients often present with anovulation, hyperandrogenism, obesity, metabolic syndrome, and infertility. Prepregnancy insulin resistance is common among women with PCOS and may play a major part in the pathogenesis of gestational diabetes. In addition, PCOS is often accompanied by excess weight gain; about 60% of women with PCOS are overweight or obese.
Previous research has shown that PCOS is a risk factor for gestational diabetes independent of obesity, while other research has shown that obesity has an important effect on this risk.
For the current study, the researchers used causal mediation analysis to elucidate more clearly the effect of obesity on the development of gestational diabetes among patients with PCOS. No previous study has used causal mediation analysis to examine this relationship.
Using data from linked universal health databases in Ontario, the researchers analyzed data on 1,268,901 births between 2006 and 2018. Of these births, 386,748 were associated with maternal PCOS.
The rate of gestational diabetes was higher among women with PCOS (60.2 per 1000 births), compared with women without PCOS (48.6 per 1,000 births). The finding resulted in an adjusted relative risk of 1.05. Obesity mediated 89.7% of this association.
“We hope that these data will inform preconception counseling and gestational diabetes screening in pregnant women with PCOS,” said Dr. Velez. “We have the data now to counsel our patients on the importance of weight management before pregnancy. But we need more resources, such as specialized clinics, to help these patients cope with managing their weight. We can tell our patients to work on their weight management, but they need much more support from the health care system.”
Results ‘not surprising’
Commenting on the study, Francine Hippolyte, MD, vice chair of obstetrics and gynecology at Long Island Jewish Medical Center, Katz Women’s Hospital, New Hyde Park, N.Y., said that the results are “not at all surprising.” Dr. Hippolyte was not involved in the research.
“We do know that PCOS is and should be treated as a metabolic syndrome. It’s a lot more than just infertility or changes or abnormalities with one’s menstrual cycle. It impacts a woman’s risk for diabetes, prediabetes, and abnormal lipid profile, regardless of whether or not she is obese,” said Dr. Hippolyte.
She agrees with the need for specialized clinics to help such vulnerable patients manage their weight.
“It would be great if insurances would cover things like nutritional counseling or have nutritionists on their roster so that patients can easily access that service. Many patients want to do right, especially preconceptually, but it is difficult without having access to resources. Unfortunately, as clinicians, we’re not as well versed in nutrition as we would like to be or should be, so we need a multidisciplinary approach. We need nutrition and weight loss clinics and proper services to really help these patients.”
The study was supported by the Canadian Institute of Health Research and ICES. Dr. Velez and Dr. Hippolyte reported no relevant financial relationships.
A version of this article first appeared on Medscape.com.