The finding comes from analysis of data on more than 175,000 pregnant women treated in Kaiser Permanente hospitals from 1999 through 2005. The researchers focused on the 2,784 births to women who had type 1 or type 2 diabetes at the time they became pregnant. They did not have gestational diabetes, which develops for the first time during pregnancy.
In 1999, eight out of 1,000 births were to women who had type 1 or type 2 diabetes. By 2005, this more than doubled to 18 out of 1,000 births. And this number includes only women who successfully gave birth. Diabetes is a major risk factor for miscarriage, notes study researcher Jean M. Lawrence, MD, MPH, of Kaiser Permanente.
"Type 1 and type 2 diabetes are more dangerous for the baby and potentially harder to treat than gestational diabetes," Lawrence tells WebMD. "It means that diabetes is with you the entire pregnancy -- particularly the crucial early stage of pregnancy, before women even know they are pregnant. At this stage, high blood sugar can cause miscarriage and birth defects."
Nobody knew Sandy Kaplan had diabetes when she had a miscarriage. For most of their 10-year marriage, the 36-year old San Francisco Bay-area woman and her husband have been trying for another pregnancy.
"I was not really working on diabetes control," Kaplan tells WebMD. "I was a very heavyset girl. The doctors all said I just needed to lose weight, but I said, "Yeah yeah yeah, uh-huh, it's the old fat girl thing again."
That changed when Kaplan finally got pregnant for the second time.
"When I got pregnant something snapped in my head. I thought, 'If I really want to have a baby, I need to take care of myself," she says. "So I went to Kaiser, and they got me into a program with a nutritionist. It is really, really hard to lose weight when you are pregnant. I was about 300 pounds -- but I was down to around 230 when I had my daughter."
That daughter, now 4 months old, is perfectly healthy -- which means Kaplan dodged a bullet, says Celia Dominguez, MD, assistant professor of gynecology and obstetrics at Atlanta's Emory University.
"Whether it's type 1 or type 2 diabetes, when it is not well controlled, even if the baby does make it there is a high risk of anomalies, ranging from 'mermaid' babies without bottom limbs to all kinds of other problems," Dominguez tells WebMD. "If mother's diabetes is not diagnosed or in poor control, it can mean significant handicap to the child."
Although Lawrence's study did not distinguish between type 1 and type 2 diabetes, both she and Dominguez believe the increase in prepregnancy diabetes is due to a surge in obesity-linked type 2 diabetes.
Dominguez says several trends are crashing together: growing obesity, a delay in pregnancy, and a tendency for everyone to get heavier as they get older.
"We are literally now changing the face of pregnancy to encompass a little more high risk," she says. "And with that increase in maternal weight unfortunately come other problems like high blood pressure. So do I see more pregnant women with type 2 diabetes than I did two decades ago? Yes."
Diabetes Control Important Even If No Pregnancy Planned
Half of all pregnancies are unplanned, Lawrence says. This means that sexually active women of childbearing age should keep their diabetes under tight control even if they aren't currently planning to have a baby.
Here are some tips from Kaiser Permanente.
Even if you aren't pregnant:
- Get screened for diabetes with a fasting blood sugar test or the glucose tolerance test.
- If you have type 1 or type 2 diabetes, work with your health care professional to get your blood sugar under control.
- If you have prediabetes or type 2 diabetes and are overweight, work on reducing your weight before becoming pregnant.
If you are pregnant:
- Discuss screening for gestational diabetes with your doctor. Some women might need to be screened at the beginning of their pregnancy and others between 24 and 28 weeks of pregnancy.
- If you are pregnant with diabetes, work with your provider on reducing your blood sugar to the goal range and establish a routine of exercise like walking. Always talk with your doctor before you start exercising.
- After giving birth, women with gestational diabetes should have their blood sugar level tested to make sure it returns to normal.