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Obesity in Pregnancy – Why it’s Risky

The newly released 2010 Dietary Recommendations for Americans highlighted the seriousness of the obesity epidemic in the United States. Being overweight or obese doesn’t just affect your personal health. During pregnancy, your weight has the potential to negatively impact your developing baby’s health as well.

Obesity in the United States has more than doubled in the last three decades. According to CDC Obesity Trends, in the late 1970s, only 15 percent of adults were obese. By 2008, this rate has increased to 34 percent. Today, an estimated one in five women is obese at the beginning of her pregnancy. (You are considered obese if you have a body mass index (BMI) that is over 30.)

Many overweight and obese women can go on to have healthy pregnancies and babies, however you should be aware that maternal obesity during pregnancy is associated with many complications, including:

  • Potential birth defects
  • Fetal death (miscarriage or stillbirths)
  • Gestational diabetes (diabetes that develops during pregnancy)
  • Cesarean delivery and complications during the labor and delivery process.
  • Macrosomia (delivering a very a large baby)
  • High blood pressure in pregnancy
  • Preeclampsia – a serious form of hypertension that may place both your health and your baby’s life at risk.

The infants born to obese mothers are at a twofold risk of developing type 2 diabetes and obesity in the future. In addition, they may face birth injury due to the baby’s large size as he is moving through the birth canal.

On the positive side, the March of Dimes reports that obesity itself doesn’t increase the risk of preterm delivery (a baby born before 37 weeks pregnant). However, because obesity can lead to pregnancy complications, such as preeclampsia, this may lead to preterm labor.

Birth Defects related to Obesity during Pregnancy

A growing number of studies have linked obesity during pregnancy to a number of birth defects, including spina bifida (a type of neural tube defect), cardiovascular (heart) defects, cleft lip and cleft palate, hydrocephaly (an abnormal buildup of fluid in the brain), abdominal wall and limb defects.

In a research study published in a 2009 issue of the Journal of the American Medical Association, scientists examined obesity and its birth defect risk. They found that:

  • Babies born to obese mothers had more than double the risk of spina bifida (a birth defect that occurs in the first month of pregnancy when the spine does not completely close). These babies’ overall risk of other neutral tube defects was nearly twice as high.
  • The risk of cardiovascular defects, or heart defects, in these infants was 30 percent higher than infants born of average sized women.
  • Newborns of obese women also had a 20 percent risk of cleft lip and cleft palette – a birth defect that occurs when the tissue that forms the roof of the mouth and upper lip don’t join together.
  • The babies’ risk of hydrocephaly (a condition characterized by fluid on the brain) was 60 percent higher.
  • In addition, their risk of having limb reduction defects (a birth defect that occurs when a part or the entire arm or leg fails to form completely) was 30 percent higher.

Researchers do not understand why the babies of overweight women are more likely to have birth defects; however, they do have several theories.

One possible explanation is that obese women are at higher risk of type 2 diabetes and gestational diabetes. Some of these women may have undiagnosed diabetes. Maternal diabetes is a known risk factor for birth defects.

In addition, since obese women can have nutritional deficiencies, especially lower levels of folate or folic acid, this may explain the higher risk for neutral tube defects. (Folic acid is known to prevent neutral tube defects).

How Obese Women Can Reduce the Risk of Pregnancy Complications

If you are overweight and pregnant, you can lower your risk of birth defects by gaining the right amount of pregnancy weight for your size. Your obstetrician, midwife, or healthcare provider will help you develop an individual weight gain plan for your specific situation.

Recommended Weight Gain for Obese and Overweight Pregnant Women

According to ACOG (American Congress of Obstetricians and Gynecologists), they recommend that overweight women (with a BMI between 25 and 29.9) gain between 15 to 25 pounds during pregnancy. For obese women (BMI of 30 and higher) should gain to gain between 11 and 20 pounds during the 40 weeks of pregnancy.

(Women of normal weight are recommended to gain between 25 and 35 pounds during pregnancy.)

For obese women, this means that you should only gain between 1.1 to 4.4 pounds in your first trimester, and only 0.5 pounds in the second and third trimester of pregnancy. Keeping within this schedule will aid in normal fetal development, and it will help prevent pregnancy complications.

In addition, keeping within the recommended pregnancy weight gain actually helps you lose your pregnancy weight faster after delivery.

** It’s very important that you do not attempt to start a diet during pregnancy. Restricting your food intake can negatively impact your developing baby’s health. When you intentionally cut back on calories, you are also limiting nutrients to your baby. However, don’t be surprised if you do start to lose a little weight in the first trimester, due to morning sickness.

Tips to Reach Pregnancy Weight Gain Goals

Pregnant women who are overweight or obese should eat a healthy diet that contains plenty of fiber and complex carbohydrates. High-fiber foods include:

  • Fruits – such as raspberries, pears, apples, strawberries, bananas, oranges, figs, raisins
  • Whole grains, cereal and pasta
  • Legumes – including beans and peas
  • Nuts – like pecans, pistachio nuts, and almonds
  • Vegetables – including carrot, Brussels sprouts, sweet corn, turnip greens, broccoli, peas, and artichoke.

Aim for 20 to 35 grams of fiber every day. Because constipation is a common pregnancy complaint, eating enough fiber will keep you more comfortable and regular.

Complex carbohydrates also contain fiber. They include legumes (beans and peas), starchy vegetables, and whole grain bread and cereal.

In addition, because the risk of neutral tube defects is higher in obese pregnant women, it’s important that overweight women get enough folic acid in their diet. You can find folic acid in many leafy green vegetables, fruits, peas and nuts.

Obese pregnant women should plan their diet with a nutritionist or healthcare provider to make sure that they are getting all the nutrients that their baby needs, while staying within the weight gain goals.

Exercising during pregnancy is another way to control excess weight gain. With a doctor’s approval, overweight women may consider moderate exercises, such as brisk walking, swimming, riding a stationary bike, and pregnancy aerobics classes.

About the author: DP Nguyen is founder and editor of Hip Chick’s Guide to PMS, Pregnancy and Babies. She’s an expert pregnancy and women’s health blogger. She is NOT a medical doctor and does NOT offer medical advice. Connect with her on Google+, Twitter and Facebook.

{ 9 comments… add one }
  • birth injury March 11, 2011, 9:18 am

    Mothers are apprehensive about making a birth injury compensation claim as they believe that they are claiming against an individual with whom they may have built up a friendly relationship during pregnancy.

  • Martincspencer February 12, 2011, 2:40 pm

    How do we deal with mothers who have Diabetes Type I? Is having diabetes earlier in life poses a risk in pregnancy? Or are Type I diabetics even allowed to give birth?

    • DP February 12, 2011, 8:14 pm

      Type 1 Diabetics are considered ‘high risk.” It just means that your pregnancy will need to be monitored more closely, since you are at increased risk of complications, birth defects, etc. But if you keep your glucose levels well-controlled and you monitor your pregnancy with your doctor, you should be fine.

      Yes, Type 1 Diabetes are allowed to give birth. But they are at higher risk of having a larger baby, so that may cause a doctor to suggest a c-section.

  • Annegwells February 12, 2011, 2:38 pm

    Do mothers with pregnancy induced diabetes will still have diabetes after giving birth and for the rest of her life?

    • DP February 12, 2011, 8:12 pm

      Hi! Gestational diabetes (what you’re called ‘pregnancy induced diabetes’) usually goes away after you deliver the baby. Only in some cases does it increase your risk of diabetes, but in a majority of the cases, it goes away after the pregnancy ends.

      But if you have gestational diabetes in one pregnancy, you will usually get it again in future pregnancies.

  • Mary at SweepingMe February 4, 2011, 3:48 am

    Well, I am Obese and had two healthy babies. 10 fingers/toes/no birth defects. One daughter is ADHD but that could be because my brother and husband and sister have it also…Very interesting article.

    • DP February 4, 2011, 2:50 pm

      Obesity just increases the risk of health problems. Many overweight women who receive good prenatal care during pregnancy go on to have perfectly healthy baby with no problems at all. 🙂

  • Terry Bennie February 2, 2011, 9:29 pm

    This is a great article, came over and am following you from Bloggy Moms. Thanks for leaving me a comment over there.


  • Jules February 2, 2011, 12:21 am

    Such an interesting article. Also worth mentioning is that children of obese parents are more likely to struggle with obesity as well. I particularly like the blurb about pregnancy goals focusing on healthy eating habits during pregnancy.

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