How To Lose Weight Safely While Pregnant And When Would Your Doctor Recommend It

In an ideal world, every facet of your pregnancy plan runs smoothly, and you’re at your ideal weight prior to becoming pregnant. However, for a lot of women, this isn't always possible. While getting pregnant is exciting, it can easily become a weight dilemma for overweight women. This is because gaining weight is inevitable during pregnancy.

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Is trying to lose weight during pregnancy safe?

Doctors don't typically suggest that women lose weight while they're pregnant. Instead, they encourage them to focus on exercise and getting enough nutrients to keep both themselves and their unborn baby healthy.

In fact, weight loss isn't appropriate for pregnant women who, at the time of getting pregnant, were already at a healthy weight. But, what happens if you're already carrying extra weight before getting pregnant?

Being obese (having a body mass index 30.0 or higher) during pregnancy can put you at increased risk of various health issues, including the following¹:


Preeclampsia is a severe type of gestational hypertension that typically occurs soon after giving birth or in the second half of your pregnancy. It can cause your liver and kidneys to fail² and in rare cases, it can cause:

  • Heart attack

  • Seizures

  • Stroke

Other risks might include problems with fetal growth and with the placenta.

Gestational hypertension

This is high blood pressure that begins during the second half of your pregnancy. It can cause severe complications, such as poor fetal growth and stillbirth³.

Obstructive sleep apnea (OSA)

Sleep apnea is a disorder where you stop breathing for brief periods while sleeping. Sleep apnea can increase your risk of preeclampsia, high blood pressure, lung and heart problems, and cause fatigue during pregnancy.

Gestational diabetes

High blood sugar (glucose) levels during pregnancy can increase your risk of giving birth to a very large baby. It can also increase your chance of requiring a C-section (cesarean birth). If you've had gestational diabetes, you also have a greater risk of diabetes mellitus down the road. Unfortunately, your children do as well.

Growing research⁴ shows that weight loss during pregnancy may potentially be beneficial, for some women who are obese and have a high body mass index over 30. However, this would only be under strict guidance by a dietician and doctor.

When your doctor might recommend losing weight during pregnancy

For most women who are pregnant, weight management is a safer option than any type of substantial weight loss. Even though there are some benefits of a lower BMI while you're pregnant, weight loss isn't always appropriate for all women.

This concern comes partly from certain traditional methods of weight loss — exercise and calorie cutting. It's essential to exercise and watch the number of calories you're consuming while you're pregnant, but overdoing it can possibly harm your baby.⁵ This is why many doctors don't recommend losing weight while pregnant unless you have a significantly high BMI. You should discuss your concerns with your doctor.

Your doctor will work with you to make the absolute safest choices for you and your baby. After your baby is born, you can always sit down with your doctor and come up with a healthy plan for weight loss.

How to lose weight safely while pregnant

Your best weight-loss approach is through a gradual, but consistent plan with a focus on healthy lifestyle changes. Losing weight gradually, under your doctor's supervision, is always best for your baby and your body.

If your doctor suggests that you do lose some weight, here are four ways to do so safely while you're pregnant:

1. Know the amount of weight you need to gain

When you're already carrying excess weight during pregnancy, you might be overly focused on weight. However, you have a growing baby inside of you! So some weight gain is to be expected, and it’s essential that you know how much weight gain is a healthy amount.

The CDC has guidelines for pregnancy weight gain⁶ that you can follow, based on your starting weight before becoming pregnant:

  • Gain between 11 and 20 lbs if you're obese (BMI of 30 or more)

  • Gain between 15 and 25 lbs if your BMI is between 25 and 29.9

  • Gain between 25 and 35 lbs if you're at a normal weight (BMI of 18.5 to 24.9).

2. Maintain a healthy diet and exercise routine

According to the March of Dimes⁷, most women require an extra 300 calories a day while they're pregnant.

Women who are already underweight might have to increase the number of calories they take in, while women who are overweight may not have to increase their caloric intake.

Regular physical activity and a healthy diet will help boost your overall health while you're pregnant, as well as the health of your baby. While you may naturally lose some weight because of these lifestyle changes you're making, you shouldn't make these changes with the goal of losing weight.

The March of Dimes also provides a sample week menu⁸ that gives examples of healthy food choices while you're pregnant.

Along with focusing on eating healthily, you should also speak with your doctor about physical exercise while you're pregnant. Exercise will not only burn calories, but it can also provide you with stress-relieving benefits. Talking with your doctor about exercise is important as it might not be safe in certain pregnancies.

There are different guidelines for physical activity while pregnant, but unless your doctor advises otherwise, many experts suggest engaging in about 30 minutes of physical activity each day on most days of the week, such as:

Doctors recommend you don't exercise at extremely high altitudes and avoid contact sports while pregnant.⁹

3. Address weight issues early in pregnancy

While you're naturally going to gain weight from your pregnancy, most of this weight gain occurs in your second and third trimesters. During the last two months of your pregnancy, your baby is growing rapidly. You can't control the weight gain linked with your growing baby and the supporting components like the placenta. So, the best thing you can do is address any weight issues early in your pregnancy.

The journal Obesity published a study¹⁰ that reported some weight intervention success among pregnant women. Researchers found that the women who were given advice between weeks seven and 21 of their pregnancy had fewer chances of gaining excess weight in their third trimester. They also benefited from attending support group meetings on a weekly basis.

This is only one example of how planning early can help prevent excess weight gain. It's important you work closely with your doctor to come up with an early plan if you are trying to control how much weight you gain or lose during your pregnancy. Your doctor can also provide you with a referral to a dietitian for meal planning and further advice.

4. Cut down on your calorie intake

Reducing your daily intake of calories is the first way of losing excess weight, under your doctor's guidance, of course. The most common reason for weight gain is eating more calories than you're burning off. It takes a deficit of 3,500 calories for you to lose one pound¹¹. Over a one-week span, this will equate to around 500 calories you cut out each day.

Before you cut this number of calories from your diet, however, it's important you know the exact number of calories you're really eating, by keeping a log. This is where it can help to work with a dietitian and go over food plans.

The right number of calories¹² for most normal-weight pregnant women are:

  • First trimester: Around 1,800 calories a day

  • Second trimester: Around 2,200 calories a day

  • Third trimester: Around 2,400 calories a day

If you tend to consume a lot more calories than this, you'll want to consider cutting back slowly. For instance, you can:

  • Cut out condiments

  • Eat smaller portions

  • Eat fruit instead of baked goods

  • Try plant-based fats (i.e. olive oil) instead of unhealthy fats (i.e. butter)

  • Choose water over a soda

  • Swap refined carbs with vegetables

  • Avoid a lot of junk food, like candy or chips.

You'll also want to take a daily prenatal vitamin. This will help ensure you're consuming all the nutrients both your body and your baby need. Folate is particularly important since it reduces your risk for birth defects.¹³

The lowdown

If you want to know how to lose weight while pregnant or at least manage how much weight you gain, be sure to talk with your doctor and create a plan early on in your pregnancy. Always talk with your doctor first before you attempt to lose weight while pregnant.

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