Is It Safe to Be Skinny While Pregnant?

Medically Reviewed by Traci C. Johnson, MD on April 23, 2023
3 min read

Many people tend to be concerned about their weight, and this can often include women who are pregnant. If you naturally have a skinny build, you may be concerned about how carrying a baby can affect your body. When you are pregnant, you should reconsider the normal notions of how small or large your body should be.

Because "skinny" is a relative term, it means something different to every person. With such a loose definition of skinny, it’s up to you and your doctor to decide the safest weight gain while you are pregnant

"Skinny" is not a medical term. It usually refers to someone whose body is slimmer than the average body weight for a given height and age range. So, what's considered skinny can look different depending on how old you are and how tall you are.

Pregnancy is an experience during which you must take special care of yourself, and often welcome weight gain. When you are growing another human being inside your belly, weight gain is natural. As your body works to accommodate your baby, you should be thinking about how to do your part to stay healthy. 

Being radically underweight during your pregnancy can be dangerous and affect you and your child even after conceiving. It is essential to understand what that looks like and what it may mean. 

The Centers for Disease Control have created a comprehensive pregnancy weight gain chart by your body mass index (BMI), which you can calculate here. Here's a simple breakdown of what you can expect to gain:

  • BMI less than 18.5= 28-40 pounds
  • BMI 18.5-24.9= 25-35 pounds
  • BMI 25-29= 15-25 pounds
  • BMI greater than 30= 11-20 pounds

Your doctor will regularly weigh you throughout your pregnancy to monitor this. During each appointment, make sure to speak with your doctor about your weight to correctly craft a treatment plan.

The First Trimester

During your first trimester (assuming you are not underweight), you only need to gain around one to four pounds.

After the First Trimester

As your pregnancy progresses and the baby grows, so should you. After the first trimester, you should be gaining around one pound each week. 

Steady weight gain is the best way to go about this process. You want to gain weight, but in a healthy way that is proportional to the growth of your child.

Eat a healthy diet. You can gain weight in a healthy way by eating a balanced diet of vegetables, grains, and protein sources. Eating extra cheese, dairy products, and fresh fruits can also help get some extra nutrients in. Try to stay away from processed, sugary, fried, or overly fatty foods. Think about eating healthful and nourishing foods as outlined by the CDC and other organizations. 

Count your calories. Calculating how much weight you need to gain and how many extra calories you should be eating a day can help relieve stress about gaining too much or too little weight. However, these are just guidelines. Don't worry if your body doesn't perfectly meet them. While it is essential to gain weight during pregnancy, it is also important to remain calm and avoid pushing your body too far. 

Stay active. It's also a great idea to keep up your physical activity and maintain your muscles while pregnant. The CDC recommends that pregnant women complete around two hours of light aerobic exercise or brisk walking each week. Staying fit is helpful for most women and also may help you gain weight. 

Gaining weight throughout your pregnancy is important for your baby's and your own health. Being underweight while pregnant is linked to malnutrition and underweight babies. There have even been some loose correlations to underweight pregnancies and intellectual difficulties in children. 

Being overweight during your pregnancy can present its own problems, like gestational diabetes, blood pressure disorders, and possibly needing a C-section. Some of those same health problems can arise if you try to gain weight too quickly or in an unhealthy way. 

While you're pregnant, maintaining a healthy weight to support your child takes a balance of many lifestyle changes. You must find a trusted doctor and visit them regularly to ensure a smooth and safe pregnancy and delivery.