"Our results indicate that gestational diabetes prevalence is high in the U.S.," said lead researcher Carla DeSisto, an epidemiology research fellow at the U.S. Centers for Disease Control and Prevention.
Gestational diabetes develops in women who have never had diabetes before but who have high blood sugar during pregnancy. As with type 2 diabetes, obesity is a significant risk factor for gestational diabetes. The increased prevalence of gestational diabetes has closely paralleled the rise in obesity, according to background information in the study.
Gestational diabetes can have short- and long-term effects for both mother and baby.
Dr. Alessandro Acosta, a neonatologist at Miami Children's Hospital, noted that the condition can cause the baby to be abnormally large, which may result in damage to the baby's shoulders during birth. Many of these babies are so large they need to be delivered by cesarean section, he said.
The problems caused by gestational diabetes don't end at delivery. "The bad news is that down the road these women are at risk for developing type 2 diabetes," he said.
DeSisto added: "Women who are diagnosed with gestational diabetes have more than a seven-fold increased risk of developing type 2 diabetes in the five to 10 years after delivery. Children born to mothers with gestational diabetes are also more likely to develop pre-diabetes."
Although the exact causes of gestational diabetes aren't known, one explanation is that hormones from the placenta block the action of insulin in the mother's body, according to the American Diabetes Association. This makes it hard for the mother to use insulin, so she may need up to three times as much insulin to properly use the sugar in her body.
Obesity is another possibility, DeSisto said. "Other researchers have reported that gestational diabetes has been steadily increasing consistent with the rise of obesity," she said.
Obesity has also been linked to insulin resistance, which blunts the effect of insulin and allows blood sugar levels to rise, according to the American Diabetes Association.
"Preventing obesity is a key component of well woman care and diabetes prevention. Furthermore, maintaining a healthy weight throughout the reproductive years benefits women and improves the health of any future pregnancies," DeSisto said.
Acosta agrees that gestational diabetes has become more of a problem than it once was and the increases in obesity may be the reason. Moreover, women who develop the problem are less likely to exercise and eat a healthy diet, he said.
"You have to control your diet. You have to eat healthy. You have to have some level of physical activity, so frequent exercise is important," he said.
If these lifestyle changes don't do the trick, then medications to lower blood sugar, such as insulin, may be used, Acosta said.
Acosta noted that the best treatment is prevention. Women who are even thinking about having children should start eating a healthy diet and exercising as part of their planning, he said.
For the study, DeSisto's team used the Pregnancy Risk Assessment Monitoring System questionnaire as well as state birth certificate records to compare rates of gestational diabetes from 2007 to 2008 with that of 2009 to 2010. They found no significant difference in the prevalence of gestational diabetes during these years.
It's difficult to know the exact prevalence of gestational diabetes because different medical groups have different definitions for what constitutes gestational diabetes. State reporting of the condition on birth certificates also may vary. The data from this study indicates that the prevalence of gestational diabetes is between 4.6 and 9.2 percent of all pregnancies.
The incidence varies by geographical area, according to the study. Wyoming and Utah had the lowest rates of gestational diabetes, and New York City and Rhode Island had the highest. The authors say most of the state by state difference appears to be related to obesity levels.
The report was published June 19 in Preventing Chronic Disease.
For more information on gestational diabetes, visit the American Diabetes Association.