About 14% of women will develop diabetes while pregnant, a condition known as gestational diabetes.
It's linked with obesity and older age, and the number of cases is growing although they usually resolve by the time of delivery.
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Now, a new study delivers reassuring news for women hit by gestational diabetes: The condition will not raise their long-term odds for breast cancer.
The study was led by Maria Hornstrup Christensen, of the Steno Diabetes Center Odense at Odense University Hospital in Denmark.
Her team tracked outcomes for over 708,000 Danish women who gave birth (at an average age of 28) between 1997 and 2018.
None had any history of diabetes or breast cancer before their pregnancy, and 24,140 (3.4%) of the women were diagnosed with gestational diabetes during one or more pregnancies.
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The women's health was tracked for an average of almost 12 years, over which time 7,609 of the women developed breast cancer.
Women who'd had gestational diabetes had no higher odds of developing breast cancer than those who hadn't, Christensen's team found. That was true for breast cancer overall, premenopausal breast cancer and postmenopausal breast cancer, they added.
The finding held true even after multiple factors -- age, smoking status, pre-pregnancy weight, number of offspring, ethnicity, income, occupation, education and pre-existing health problems, such as high blood pressure, were taken into account.
"It will be reassuring for women who have had gestational diabetes to know that they are not at higher risk of developing breast cancer," Christensen said in a meeting news release.
Her team will present its findings in September at the upcoming Annual Meeting of the European Association of the Study of Diabetes in Madrid.
Christensen stressed that even though gestational diabetes doesn't have links to breast cancer, women who experience it still need to take care of their health going forward.
They "need to be alert to the fact that they are at higher risk of some conditions, including type 2 diabetes," Christensen said.
Gestational diabetes has also been tied to upped risks for heart disease, metabolic syndrome, chronic kidney disease and mental health conditions, including postnatal depression, according to background information from the researchers.
Because the new findings are to be presented at a medical meeting, they should be considered preliminary until published in a peer-reviewed journal.