CHAPTER 24
PREGNANCY DIABETES: RISKS FOR BABIES AND MOMS
Inside the womb, a growing baby demands more and more fuel for healthy growth and development. Behind the scenes, a “silent partner” makes sure she gets it: Unseen and unfelt, pregnancy itself quietly reprograms your blood sugar control system to deliver extra energy to a rapidly developing child.
The process is elegant, ancient, and unstoppable. Hormones secreted by your placenta make your own body increasingly insulin resistant (a process that stops with childbirth). Your blood sugar rises—providing your baby with extra energy to grow on.
But for at least 6 percent of pregnant women, this recipe for prenatal “baby food” goes awry. Blood sugar soars too high, leading to gestational diabetes. It’s a threat for mom and baby alike, raising a woman’s risk for preterm birth, difficult labor, Caesarean section, urinary tract infections, dangerous pregnancy high blood pressure (called preeclampsia), and type 2 diabetes after pregnancy. For babies, gestational diabetes increases the odds for higher birth weight and injury during delivery, as well as perilous low blood sugar, jaundice, and breathing problems after birth.
“It’s important to detect and treat gestational diabetes as early in the pregnancy as possible,” says Russell K. Laros Jr., MD, professor of obstetrics and gynecology and reproductive sciences at the University of California, San Francisco, and a specialist in high-risk pregnancies.
Equally important: Doing all you can to lower your risk for gestational diabetes before you become pregnant. Some risk factors are outside your control, including your age (being over 25), ethnicity (Hispanic, African American, Native American, or Pacific Islander heritage), and genetics (family history of type 2 diabetes). Yet a growing stack of research shows that controlling three factors before concep-tion—what you eat, how much you move, and the number on your bathroom scale—can significantly lower your odds for developing diabetes during pregnancy.
RISK CHECK: IS GESTATIONAL DIABETES IN YOUR FUTURE?
Answer the questions below to determine your odds for gestational diabetes.
1. Are you a member of a high-risk ethnic group (Hispanic, African American, Native American, or Pacific Islander)?
Yes No
2. Are you overweight or obese?
Yes No
3. Are you related to anyone who has diabetes now or had diabetes in their lifetime?
Yes No
4. Are you older than 25?
Yes No
5. Did you have gestational diabetes with a past pregnancy?
Yes No
6. Have you had a stillbirth or a very large baby with a past pregnancy?
Yes No
7. Do you have a history of abnormal glucose tolerance?
Yes No
Scoring
• If you answered yes to two or more of these questions, you are at high risk for gestational diabetes.
• If you answered yes to only one of these questions, you are at average risk for gestational diabetes.
• If you answered no to all of these questions, you are at low risk for gestational diabetes.
TAKE CONTROL OF YOUR HEALTH—AND YOUR BABY’S
Extra weight, inactivity, and a high-fat, high-sugar diet mute your body’s response to insulin, the hormone that escorts blood sugar into cells. If you are not pregnant, this insulin resistance can persist, undetected, for years without progressing to full-blown diabetes.
But pregnancy changes all the rules. Suddenly, your body is storing new “mommy fat” on your hips and torso. At the same time, your placenta is pumping hormones including human placental lactogen, progesterone, leptin, and tumor necrosis factor alpha into your bloodstream, reducing your body’s sensitivity to insulin. If you were already insulin resistant when you became pregnant, these changes can push your blood sugar up to dangerous diabetic levels.
Your prepregnancy weight is a strong predictor of gestational diabetes risk. If you’re lean, your odds are about 3 percent; if you’re overweight, they double. An obese woman’s risk is three to four times higher than normal, say Harvard School of Public Health researchers who followed the health of 14,613 nurses for 5 years as part of the landmark Nurses Health Study.
Your weight can also dictate just how dangerous gestational diabetes will be. Among 624 Canadian women who all had pregnancy diabetes, those who weighed the most prior to pregnancy were three times more likely to have a Caesarean section and four times more likely to develop preeclampsia.
Meanwhile, overweight is putting more and more women at risk for gestational diabetes. When researchers at the University at Buffalo in New York reviewed the health records of 79,000 women who became pregnant between 1999 and 2003, they found that the number who were overweight at conception rose 11 percent in just 5 years—and the number who were obese rose 8 percent.
“Obese patients who become pregnant are at increased risk of developing gestational diabetes, as well as pregnancy-related hypertension, preeclampsia, neonatal death, and labor complications,” says John Yeh, MD, lead author and chair of the department of gynecology/ obstetrics at the university’s medical school.
WHY WAIT? TEST EARLY FOR LOWER BLOOD SUGAR
New research suggests testing for gestational diabetes just 2 months earlier than usual—at 16 weeks rather than the standard 24 to 28 weeks—can cut complications dramatically. Yet early tests aren’t the norm for most high-risk moms-to-be, a big group comprising more than half of all pregnant women.
Gynecologists have long thought that the standard blood sugar test yielded accurate diabetes results only in the 24th week of pregnancy or later. But when Duke University researchers screened 255 women for gestational diabetes during their 16th week of pregnancy, then rechecked at 24 weeks, they found that early tests were 99.4 percent accurate. “Screening at 16 weeks is a better predictor of gestational diabetes,” says Gerard Nahum, MD, associate clinical professor in Duke University Medical Center’s department of obstetrics and gynecology and lead author of the Duke testing study. “It’s more sensitive than screening later and allows us to focus earlier on women who are at greatest risk. It’s also a more practical screening technique because blood samples drawn during early pregnancy for other tests can also be used for this purpose.”
Earlier testing could cut the number of spontaneous premature births related to GD in half, say Spanish researchers who tracked 235 women with an early diagnosis of GD and another 189 diagnosed in the sixth month of pregnancy, between 24 and 28 weeks.
The check for gestational diabetes: a simple oral glucose tolerance test, in which you fast for 8 to 12 hours, then have a fasting blood sugar check. Next, you drink a sugary beverage containing 100 grams of glucose and have your blood sugar measured over the next 3 hours. You’ve got gestational diabetes if you have any two of these results: fasting blood sugar over 95 mg/dl; blood sugar of 180 mg/dl 1 hour after drinking the sugary beverage; 155 mg/dl after 2 hours; 140 mg/dl after 3 hours.
BLOOD SUGAR’S DANGERS FOR MOMS AND BABIES
Among the ways gestational diabetes can threaten a woman’s health during pregnancy:
• Nearly double the risk for preeclampsia. Pregnancy-related high blood pressure can lead to fatal seizures for mothers-to-be and to premature delivery, low birth weight, and even stillbirth. When obstetricians at St Luke’s–Roosevelt Hospital Center, University Hospital of Columbia University in New York, tracked the records of 1,664 women with gestational diabetes, they found that one in 10 also had preeclampsia.
• Twice the likelihood of Caesarean section. Up to 30 percent of all women with gestational diabetes have Caesarean sections, compared with 17 percent of women without pregnancy diabetes, according to the federal government’s Agency for Healthcare Research and Quality.
• A 42 percent higher risk for unplanned preterm birth. Researchers from the Kaiser Permanente health systems in Oakland, California, discovered this risk when they examined the birth records and blood sugar levels of 46,230 women.
• An almost total guarantee you’ll develop full-blown type 2 diabetes later. About 10 percent of women with gestational diabetes progress to diabetes within a year or so of giving birth; 70 percent are diabetic within a decade. After 28 years, 92 percent will have diabetes, say researchers from Helsinki University Hospital in Finland.
For babies, the risks include:
• High birth weight—9 pounds and up. This can lead to the baby suffering a fractured collarbone or injury to nerves in the neck during delivery.
• Low blood sugar after birth. In the womb, your baby’s pancreas churns out extra insulin to help control extra blood sugar from your body. After birth, when your baby no longer receives blood sugar from you, the extra insulin can push her blood sugar low enough to cause seizures and nervous system damage.
• A two- to sixfold higher risk for preterm birth and admission to the neonatal intensive care unit, report University of Toronto researchers who tracked the offspring of 624 pregnant women with blood sugar problems. Babies can have jaundice and breathing problems, too.
SMART SOLUTIONS TO PREVENT GESTATIONAL DIABETES
If you’re planning a pregnancy, here’s how you can use the Sugar Solution plan to defeat gestational diabetes before it starts. (Note: If you’re already pregnant, see your doctor. The Sugar Solution isn’t designed to meet the special nutritional and caloric needs of pregnant women.)
Go low-glycemic for less insulin resistance. Eating foods that keep blood sugar lower and steadier—such as steel-cut oats, barley, and whole grain breads instead of instant oatmeal, white rice, and white bread—improved insulin sensitivity twice as much as following a low-fat diet in a University of Minnesota study of 39 overweight women and men, ages 18 to 40. Their food choices and menu plans were very similar to the Sugar Solution eating plan: lots of fresh produce, whole grains, and good fats (even dessert!) in place of refined carbohydrates and saturated fats.
Lace up your sneakers, haul out your bicycle. Exercise tunes up your body’s insulin sensitivity. Getting 4 hours of activity per week prior to pregnancy cut gestational diabetes risk 76 percent in a study of 909 women conducted by researchers from Seattle’s Swedish Medical Center.
Already pregnant? Ask your doctor about the best gentle exercise routine for you. University of Buffalo researchers who followed 12,799 pregnant women found that overweight women who performed any amount and type of weekly exercise cut their risk for gestational diabetes in half. To exercise safely during pregnancy, first check with your doctor to be sure it’s right for you. Keep workouts to less than 45 minutes so your body temperature stays within safe levels. Sip water before, during, and after your workout. And think gentle, not marathon. This is not the time to increase your fitness level. A half-hour stroll around the shopping mall, a neighborhood walk, and a slow half-hour swim each week may be all you need.
Give yourself the relaxation advantage. Get enough sleep, and take time to pursue serenity. Plenty of research finds connections between being well rested and a lower risk for insulin resistance and diabetes. Shaking off stress can be even more effective: Stress hormones can unleash extra blood sugar, trigger junk food binges, and pack extra calories onto your midsection as fat (a risk factor for insulin resistance).
Another reason to learn the art of ahhh now: Prenatal researchers have found profound links between a pregnant mom’s stress levels and her child’s later health status. In one study of 74 ten-year-olds, researchers from Bristol University in England found that cortisol levels in saliva samples were highest among kids whose moms had been the most anxious late in pregnancy.
Stop smoking. It’s bad for your health, bad for your baby’s—and it raises your risk for gestational diabetes by 50 percent.
Schedule a fasting blood sugar check 6 to 12 weeks after you give birth. Once you’ve had gestational diabetes, your risk for type 2 diabetes will remain significantly higher for the rest of your life (as will your risk for developing gestational diabetes during any subsequent pregnancies). Your doctor should test your blood sugar within 3 months of delivery, then recheck annually to catch diabetes early.
IF YOU ALREADY HAVE TYPE 2 DIABETES…
The American Diabetes Association recommends that women with type 1 and type 2 diabetes have their blood sugar under tight control for at least 3 to 6 months before trying to conceive. Why? Having high blood sugar in the early weeks and months of pregnancy—when a baby’s organ systems are forming—raises the risk for birth defects two to five times higher than normal.
A new study from Boston’s Joslin Diabetes Center helps explain the risk: Excess sugar may deprive a growing embryo of oxygen during early development in the very first weeks of pregnancy—before you even realize you’re pregnant. Low oxygen may shut off development by triggering the production of cell-damaging free radicals, says lead researcher Mary R. Loeken, PhD, a scientist in Joslin’s Section on Developmental and Stem Cell Biology and an assistant professor of medicine at Harvard Medical School. “High sugar levels and low oxygen may also create an environment in which genes involved in neural tube and heart development aren’t switched on,” she says.
SMART SOLUTIONS FOR MOMS-TO-BE WITH HIGH BLOOD SUGAR
If you have type 2 diabetes before pregnancy or develop diabetes during pregnancy, these expert tips can help control blood sugar and cut complications risk.
Buy a blood sugar meter and test, test, test. Like a person with type 2 diabetes, women with gestational diabetes must test blood sugar frequently—usually upon waking, before meals, and 1 to 2 hours after each meal—to be sure it’s staying within a safe range for mom and baby. Your doctor will tell you what your blood sugar goals should be. In general, the targets for women with gestational diabetes are:
• Less than 105 milligrams of glucose per deciliter of blood (mg/dl) when you wake up in the morning
• Less than 155 mg/dl an hour after a meal
• Less than 130 mg/dl 2 hours after eating
Keep a blood sugar log where you can write down your results and also note your meals, exercise, and any unusual stresses you’ve experienced that could affect your blood sugar level.
Be prepared for insulin therapy. Up to 39 percent of women with gestational diabetes will also need insulin shots to help control high blood sugar during pregnancy. Insulin is safe and effective and won’t cross the placenta to reach your baby. Meanwhile, research suggests that a type of diabetes medication called a sulfonylurea may also work—and it’s a pill, not a shot. But more research is needed.