Understanding Obesity During Pregnancy

A pregnant woman measuring her waist
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Pregnancy and weight are something that is often talked about, though most of the discussions tend to center around gaining weight while you are pregnant. Another issue is what happens to a woman and her pregnancy when she starts pregnancy in the overweight or obese categories.

How Obesity Is Defined in Pregnancy

More and more women begin pregnancy already in the overweight or obese categories. Overweight is defined as having a body mass index (BMI) between 25 and 29.9, while obesity is defined as a BMI above 30. These are the same definitions that are used prior to pregnancy. The BMI is typically calculated on the pre-pregnancy weight and not the weight gain in pregnancy.

How Obesity Affects Pregnancy

The very first issue that someone may suffer from when trying to get pregnant while being overweight or obese is trouble conceiving. There are certain women who will suffer from issues with polycystic ovarian syndrome (PCOS), which can cause infertility or trouble getting pregnant. There are also some women who simply have a lower fertility rate called subfertility. This is in addition to the potential risks of impaired fertility from the complications of obesity in general, such as high blood pressure and diabetes.

Once pregnant, there are other potential complications, including increased risk of:

Each of these issues has their own risks associated with them. It can mean that you need to have an increased number of prenatal care visits, that you require medications or closer monitoring. This is one reason why prenatal care is so important and why it is important that it be tailored to you.

Pregnancy Weight Gain 

One thing that is clear: Even if you start pregnancy with more weight than your practitioners would like, it is still important to gain weight in pregnancy. A woman in the obese or overweight category will need to gain less weight for a healthy pregnancy, but weight gain is still encouraged.

For women who are overweight, a weight gain of 15 to 25 pounds is recommended (about two to six and a half pounds in the first trimester, and about a half pound of per week in the second and third trimesters). For women pregnant with twins, this weight gain goal increases to 31 to 50 pounds total.

If you are obese at the start of pregnancy, it is recommended that you gain no more than just over four pounds by the end of the first trimester, and gain only about a half pound a week in the second and third trimesters. The goal is to have a weight gain total between 11 and 20 pounds. If you are expecting twins, that number rises to 25 to 42 pounds total.

Losing Weight While Pregnant

It is not recommended that anyone attempt to lose weight in pregnancy. This is true no matter what your starting weight is. Dieting in pregnancy deprives your baby of needed calories. It is also thought to cause a potential problem with burning maternal fat stores potentially releasing toxins into the body. This is not to say that you should eat whatever you want. A diet that is well rounded and full of hearty foods is much better for your pregnancy and baby than a diet that is high-calorie and low-quality.

Labor in Obese Women

There are many beliefs that have been held about labor in woman who are overweight or obese. Research has helped clarify these thoughts and to put them into a modern medical context. Pregnant people who are obese may have an increased risk for:

Women who are overweight or obese categories may have a longer first stage of labor, the part where the cervix is dilating. A practitioner would be advised to provide extra time in this phase of labor and not intervene as long as the mother and baby are doing well.

Epidural anesthesia is possible for women in a higher weight category, though it may be technically more challenging for the anesthesiologist. If you fall into this category, consider a pre-labor consultation with the anesthesia department at your hospital. This way there may be fewer surprises during labor.

The second stage of labor, or pushing, was once thought to be longer for overweight or obese women. Recent research has not found that to be the case. In fact, a small study showed that these women had similar intraabdominal pressures to normal weight counterparts. That said, augmentation with synthetic oxytocin was more common. It is also an important point to note that an increased BMI seems to have a protective effect against having a third or fourth-degree laceration on the perineum.

Induction of Labor and Cesarean Birth

Cesarean section has its own set of issues in overweight and obese women. It is important to note that a planned cesarean section for weight alone does not improve the outcomes for baby or mother. The risk for needing a cesarean is not as straightforward as one might assume.

If you begin labor spontaneously, the rates of cesarean section during labor are the same for women of all weight categories. When the risk for cesarean section rises for mothers in the overweight and obese categories is when labor is induced or started artificially. While there are currently studies being done to look at what could be altered to control this rise, there are currently no recommendations for what type of induction would be the most effective.

What we do know is that women who are overweight or obese do have a higher rate of complications that would make an induction of labor the appropriate intervention. What comes next is balancing the risks of prolonging the pregnancy and the risks of induction and potential cesarean birth.

A cesarean birth is technically more challenging from the standpoint of the anesthesia team and the surgeon. This is another time when having adequately sized equipment can be very helpful for both the surgeon and the patient.

Preconception Planning for the Future

Ideally, obesity and weight-related issues are addressed prior to pregnancy. However, there have been no real studies on what is effective and what isn’t in terms of which is best. What experts do agree on is that when possible, you should lose weight. Even if it doesn’t completely resolve a health issue, any weight lost is considered beneficial.

If you are having trouble with losing weight or chose not to wait to conceive, then be sure that you are working to be as healthy as possible. Good preconceptional health screening can identify any potential health issues and you can address those prior to getting pregnant. This will help your future pregnancy be healthier.

High-Risk Label

Many overweight or obese women find themselves being forced into medical practices that are all high-risk, even in absence of chronic problems and being forced to accept interventions or testing that they may not want. This is because the majority of women in the overweight and obese category are often labeled as high-risk patients.

While being overweight or obese may increase some complications, the majority of complications that happen in pregnancies within these weight categories are because of a chronic condition which may or may not be related to the weight (for example, pre-existing blood pressure problems). However, being labeled high-risk is not the same thing as saying you will absolutely have complications in pregnancy. There is simply a greater chance of it happening.

Even with the high-risk label, a good number of women should be able to have low-intervention pregnancy and births. This largely depends on the practitioner that you chose and their guiding philosophy. As a pregnant person, you do have rights and can exercise them. This can include finding a new practitioner if appropriate.

What to Do If You Feel Like You Are Treated Poorly Because of Your Weight

Speak up. Your doctor or midwife may not realize that you are feeling bad about your care. This allows you a chance to clear the air. If you aren’t comfortable doing this in person, consider writing a letter to your provider.

As a pregnant person, you have a right to be treated respectfully and with the care that is appropriate for your pregnancy and/or medical conditions. This includes ensuring that you have appropriate medical equipment—for example, a well-fitting blood pressure cuff (instrumental in ensuring that your blood pressure is being measured adequately), scales that weigh you accurately, and furniture that fits you, including labor beds and exam tables.

If your concerns are not addressed to your satisfaction after you communicate them to your providers, consider seeking care from another group of physicians.

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