Weight Loss — Pregnancy Symptoms

Many women worry about gaining too much weight during pregnancy. During the first trimester, an expectant mother should only gain about five pounds. However, many women are shocked to learn that they can lose weight during the first trimester. Losing weight after the first trimester can be a problem, however, and you should notify your healthcare provider if you experience weight loss during the second or third trimesters, as this can possibly harm you and your baby.

During the first trimester, weight loss is not unusual and is not necessarily anything to be alarmed about. In fact, if you’re overweight or obese, your doctor may even want you to lose a few pounds during the early part of your pregnancy (although it is preferable to lose this weight before you become pregnant, if possible).

It’s important to remember that the baby is not the reason for the weight gain that normally occurs during the first trimester. Water retention and bloating are the causes of early pregnancy weight gain, as the baby is still too small to cause any major changes to your physical appearance or your weight.

Causes of First Trimester Weight Loss

According to experts, weight loss during the first trimester is not unusual, nor is it harmful to your baby. It happens more often than you might think, and it is not considered a serious problem. Many women have severe episodes of vomiting, which is sometimes caused by ordinary morning sickness and sometimes by a more severe condition known as hyperemesis gravidarum. This frequent vomiting can eventually lead to weight loss. A great way to decrease nausea and vomiting is to eat smaller portions, more often. Eating five or six small meals a day can usually prevent these symptoms.

How Much Weight Should Be Gained During Pregnancy?

This will depend on your doctor’s recommendations. Doctors usually base their judgment on the mother’s weight before pregnancy, or during the early, early weeks.

  • Women of average weight should only gain 25 pounds during pregnancy (up to 35 pounds is normal, but 25 pounds is enough)
  • Underweight women should try to gain 28–40 pounds during pregnancy
  • Overweight women should limit weight gain to 15–25 pounds during the latter stages of pregnancy

The above guidelines are meant to be applied to women within normal weight ranges. Women who are not merely overweight but actually obese, however, should gain no more than eleven pounds during the course of pregnancy.

Overweight and obese are defined by their Body Mass Index (BMI), using pre-pregnancy weight and height. A BMI greater than 25 is overweight, and greater than 30 is obese. If you are 5 feet 4 inches, you are overweight at 150 pounds and obese at 180.

Here is a link to a BMI calculator: www.nhlbi.nih.gov/health/educational/lose_wt/BMI/bmicalc.htm

Most pregnant women should gain two to four pounds during the first three months of pregnancy, and one pound every week after that until the baby is born. If the expectant mother is carrying twins, she should gain a total of 35–40 pounds, which averages out to 1½ pounds per week after the initial weight gain in the first three months.

Deliberate Weight Loss During Pregnancy

In the preceding sections we have covered unexplained weight loss during pregnancy, but if you’re pregnant and overweight, you should also know the facts about dieting and exercising to lose weight during pregnancy.

Never try to lose weight later in pregnancy. If you feel you’ve gained too much, talking with your healthcare provider about your concerns can help you establish a better diet and eating routine. Losing weight during late-term pregnancy, especially in your third trimester, can harm your baby. Getting proper nutrition throughout pregnancy is essential. The baby gains an average of half a pound per week in the final 4-6 weeks of pregnancy, so this is not a good time for the expectant mother to be cutting back on calories.

Weight loss early in pregnancy, however, may actually be healthier if you’re obese. Studies conducted at Saint Louis University showed that obese women who lost weight under medical supervision while pregnant were more likely to have babies of normal size. Obese women who did not lose any weight, on the other hand, were more likely to deliver unusually large—and less healthy babies (this condition is known as macrosomia). Those who lost weight were also less likely to require C-section delivery. According to a 2012 study published in the British Medical Journal, obese women who lost weight during pregnancy were 33 percent less likely to develop a dangerous blood-pressure condition known as pre-eclampsia. These women also had a 70 percent lower risk of high blood pressure and a 60 percent lower chance of developing gestational diabetes.

Regardless of your weight, you should consult your doctor before embarking on any sort of diet or weight-loss plan during pregnancy. Women who are not obese, even if they are overweight, can run the risk of giving birth to underweight babies if they lose too much weight while pregnant.

This page was last updated on 08/2017

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