Being overweight increases the risk of complications for pregnant women and their babies. The higher a woman’s BMI, the higher the risks. The increasing risks are in relation to miscarriage – the overall risk of miscarriage under 12 weeks is one in five (20%); if you have a BMI over 30, the risk is one in four (25%)

The more overweight you are, the more likely you are to have pregnancy complications. But there are things you can do before and during pregnancy to help you have a healthy baby. Being overweight is based on your pre-pregnancy body mass index (also called BMI). Pre-pregnancy means your BMI before you get pregnant.

If you started off your pregnancy carrying too much weight for your height, you’re far from alone. More than half of pregnant women are overweight or obese. You’re considered overweight if your pre-pregnancy body mass index (BMI) is between 25 and 29.9. (Your BMI reflects the relationship between your height and weight and is an estimate of body fat.) You’re considered obese if your BMI is 30 or greater.

How much weight to gain if you’re pregnant and overweight or obese

How much to gain during pregnancy depends on your BMI:

• If your BMI is 25 to 29.9: It’s recommended that you gain between 15 and 25 pounds by the end of your pregnancy or approximately 2 to 3 pounds per month in your second and third trimesters.
• If your BMI is 30 or higher: You’re advised to gain only 11 to 20 pounds during pregnancy.

Obesity during pregnancy puts you at risk of several serious health problems:

• Gestational diabetes is diabetes that is first diagnosed during pregnancy. This condition can increase the risk of having a cesarean delivery. Women who have had gestational diabetes also have a higher risk of having diabetes in the future, as do their children. Obese women are screened for gestational diabetes early in pregnancy and also may be screened later in pregnancy as well.
• Preeclampsia is a high blood pressure disorder that can occur during pregnancy or after pregnancy. It is a serious illness that affects a woman’s entire body. The kidneys and liver may fail. Preeclampsia can lead to seizures, a condition called eclampsia. In rare cases, a stroke can occur. Severe cases need emergency treatment to avoid these complications. The baby may need to be delivered early.
• Sleep apnea is a condition in which a person stops breathing for short periods during sleep. Sleep apnea is associated with obesity. During pregnancy, sleep apnea not only can cause fatigue but also increases the risk of high blood pressure, preeclampsia, eclampsia, and heart and lung disorders.

Obesity increases the risk of the following problems during pregnancy:

• Pregnancy loss—Obese women have an increased risk of pregnancy loss (miscarriage) compared with women of normal weight.
• Birth defects—Babies born to obese women have an increased risk of having birth defects, such as heart defects and neural tube defects.
• Problems with diagnostic tests—Having too much body fat can make it difficult to see certain problems with the baby’s anatomy on an ultrasound exam. Checking the baby’s heart rate during labor also may be more difficult if you are obese.
• Macrosomia—In this condition, the baby is larger than normal. This can increase the risk of the baby being injured during birth. For example, the baby’s shoulder can become stuck during delivery. Macrosomia also increases the risk of cesarean delivery. Infants born with too much body fat have a greater chance of being obese later in life.
• Preterm birth—Problems associated with a woman’s obesity, such as preeclampsia, may lead to a medically indicated preterm birth. This means that the baby is delivered early for a medical reason. Preterm babies are not as fully developed as babies who are born after 39 weeks of pregnancy. As a result, they have an increased risk of short-term and long-term health problems.
• Stillbirth—The higher the woman’s BMI, the greater the risk of stillbirth.

Can I diet to lose weight during pregnancy? 

Pregnancy is definitely not the time to go on a weight-loss diet: Restricting your food intake is potentially hazardous to you and your developing baby. But many plus-size women do lose weight during pregnancy without dieting.

In the first trimester, it’s common to lose weight as a result of morning sickness. Nausea can diminish your appetite, and the vomiting can cause you to miss out on calories. But even so, your baby will get all the necessary calories.

Overweight women have an extra reserve of calories in stored fat, so as your baby grows, it’s not harmful to maintain or even lose a little weight at first. What’s not okay is losing weight because you’re intentionally cutting calories (and, as a result, limiting nutrients).

Can I still have a healthy pregnancy if I am obese?

Despite the risks, you can have a healthy pregnancy if you are obese. It takes careful management of your weight, attention to diet and exercise, regular prenatal care to monitor for complications, and special considerations for your labor and delivery.

How to stay on track with weight gain if you’re overweight or obese?

Exercising and eating healthy food can help you with your weight gain goals, and both can have a positive impact on your pregnancy, reducing your risk of pregnancy problems like gestational diabetes and preeclampsia. They’ll also help you feel good during your pregnancy and beyond.

How does obesity affect labor and delivery?

Overweight and obese women have longer labors than women of normal weight. It can be harder to monitor the baby during labor. For these reasons, obesity during pregnancy increases the likelihood of having a cesarean delivery. If a cesarean delivery is needed, the risks of infection, bleeding, and other complications are greater for an obese woman than for a woman of normal weight.

Eat a healthy pregnancy diet and Exercise regularly Some women do lose weight during pregnancy if they make healthy diet and lifestyle changes, so make sure to check in with your doctor if this happens to you.

Resources:

https://www.acog.org/Patients/FAQs/Obesity-and-Pregnancy