WEDNESDAY, April 25, 2018 (HealthDay News) -- As if coping with type 2 diabetes as a teenager isn't tough enough, it turns out that many girls with the metabolic disorder also have to deal with irregular periods.
And menstrual cycles that stray from normal can lead to very heavy bleeding and cause extra cramping, said Dr. Megan Kelsey, lead author of a new study. She's an associate professor of pediatric endocrinology at Children's Hospital of Colorado and the University of Colorado School of Medicine in Aurora.
In the long-term, irregular periods can also increase the risk of endometrial cancer, the researchers pointed out in the new report.
In the study of young teen girls, "menstrual irregularities affected about one in five girls with type 2 diabetes," Kelsey said. Those girls had irregular periods even though they were all receiving a treatment for type 2 diabetes called metformin.
Kelsey noted that even in girls who made lifestyle changes or took another diabetes medication, menstrual irregularities persisted.
"They may need hormonal treatments for their menstrual dysfunction," she said.
It's likely, she explained, that a hormonal disorder called polycystic ovarian syndrome (PCOS) is the underlying cause of the menstrual abnormalities.
The study data was drawn from a large study of type 2 diabetes treatments in children. Researchers in that study looked at use of metformin (Glucophage) -- a drug that makes people more sensitive to the effects of insulin.
Insulin is a hormone that helps usher sugar from foods into cells to be used as fuel. People who have type 2 diabetes don't respond normally to insulin.
The original study also looked at use of metformin plus rosiglitazone (Avandia) and metformin plus lifestyle changes, and compared all three treatment regimens.
The new study included 190 girls with type 2 diabetes from that group. None of these girls used hormonal birth control, such as the pill or an intrauterine device (IUD).
The definition for irregular periods was having three or fewer periods in the last six months. The girls were around 14 years old. They had had type 2 diabetes between five and six years. Blood sugar control was similar for both groups.
The researchers found that 39 of the girls -- 20 percent -- had irregular periods.
Girls who had irregular periods were more overweight and obese, and they had higher levels of the sex hormone testosterone than those with predictable periods, the findings showed.
But their levels of insulin secretion and insulin sensitivity appeared similar to those with regular periods, so it doesn't seem as if the irregular periods are due specifically to type 2 diabetes, the study authors noted.
Instead, Kelsey said, these findings indicate that the irregular periods were probably due to polycystic ovarian syndrome. PCOS is often associated with excess weight, as is type 2 diabetes. And girls with PCOS are often insulin-resistant.
Kelsey added that the girls with signs of PCOS were more likely to have abnormal liver function tests, too, suggesting that they're also at risk of developing non-alcoholic fatty liver disease.
Dr. Siham Accacha is chief of pediatric diabetes at NYU Winthrop Hospital in Mineola, N.Y. She said better treatments are needed for PCOS.
"I think metformin is not the best treatment for PCOS because it only addresses one issue of PCOS -- the insulin resistance," said Accacha, who was not involved in the study.
Weight loss is one treatment that can help PCOS, she explained. "Regardless of insulin sensitivity, the biggest intervention is to lose weight," Accacha said.
Findings from the study were published online April 24 in the Journal of Clinical Endocrinology and Metabolism.
Learn more about PCOS from WomensHealth.gov.