For most women, pregnancy weight gain comes easily. But for others, the problem isn’t gaining too much weight — it’s not gaining enough. Here’s how to get your pregnancy weight gain on track, and when it’s time to see your doctor.

Why am I not gaining weight during pregnancy?

A number of factors can contribute to slow or no weight gain during pregnancy, including:

You might also not be gaining enough weight because of food aversions. If some foods turn you off, consider crackers and other snacks until you feel up to having full meals. You may even want to schedule an appointment with a prenatal nutritionist to see how you can continue to gain weight.

What is considered too little weight gain during pregnancy?

During the first trimester of pregnancy, you don’t need to gain any weight at all. You may even lose a few pounds. That’s usually perfectly okay, as long as you make up for it later on in pregnancy. 

Your pregnancy weight gain should pick up in earnest, however, by the second trimester. The least amount of weight you should gain during pregnancy depends on how much you weighed before you conceived, among other factors. If you had a higher body mass index (BMI) before pregnancy, you typically need to gain less weight than if you started out pregnancy with a lower one.

By the second trimester, you should aim to gain the following:[1]

  • Underweight (BMI under 18.5) before pregnancy: About 1 pound per week (for 28 to 40 total pounds during pregnancy)
  • Normal BMI (18.5 to 24.9) before pregnancy: Less than 1 pound per week (for 25 to 35 pounds total during pregnancy)
  • Overweight (BMI 25 to 29.9) before pregnancy: About 0.6 pounds per week (for 15 to 25 pounds total during pregnancy)
  • Obese (BMI 30 or more) before pregnancy: About 0.5 pounds per week (for 11 to 20 pounds total during pregnancy)

If you’re carrying twins, you need to gain roughly 50 percent more weight (give or take, again depending on your pre-pregnancy weight).

What happens if you don’t gain enough weight during pregnancy?

Not gaining enough weight over the course of your pregnancy can put you and your baby at greater risk of complications. Babies whose mothers gain too little weight during pregnancy are more likely to:[2]

Some babies who are born small (weighing less than 5 pounds, 8 ounces) may miss developmental milestones and have trouble breastfeeding. They may also be at a greater risk for certain illnesses and other conditions, such as digestive problems and Sudden Infant Death Syndrome (SIDS).

A lack of weight gain is usually perfectly normal in the first trimester. Tiny fetuses have tiny nutritional needs.

The same isn’t true if you’re falling short of your recommended weight gain by the second trimester. As your baby gets bigger, calories and nutrients will be increasingly in demand. To keep up, you'll need to increase your weight at a steady pace.

Remember to fill your diet with dark leafy greens, fiber (found in beans and kiwis), and other nutrient-rich foods. Your doctor or prenatal nutritionist can help create a meal plan for you.

How to gain more weight during pregnancy

It sounds obvious, but it's worth repeating. If you're eating the recommended calories during pregnancy and you're not gaining weight fast enough, you should eat more. Here are a few tips to help you put on more weight during pregnancy:[3]

Choose nutrient-dense foods 

Focus on high-quality calories filled with healthy fatsprotein and fiber. Nutrient-rich options include:

  • Avocados
  • Nuts and nut butter
  • Fatty fish (like salmon)
  • Olive oil
  • Beans 
  • Peas
  • Whole grain bread, cereal and pasta
  • Oatmeal
  • Brown rice 
  • Lean meat or poultry
  • Plain Greek yogurt
  • Dried fruit
  • Eggs
  • Cheese

Add a caloric punch to your dishes

Try dosing your dishes with an extra tablespoon of calorie-dense olive oil, butter, cream cheese, sour cream or cheese. Or toss a couple of scoops of powdered milk into hot cereal or scrambled eggs.

Some research suggests that adding protein supplements to your meals can also help you gain weight. Talk to your doctor to make sure you get the right amount, since overdoing it on protein may limit a baby’s growth.

Eat strategically

It’s important to drink plenty of water during pregnancy to stay hydrated. And fruits and vegetables are a staple of a healthy pregnancy diet. They provide your baby with folic acid, a vitamin that helps form healthy cells and reduces the risk of birth defects like spina bifida. 

That said, both beverages and calorie-light dishes can put a damper on your appetite. Instead of starting your meal with a salad or big glass of water, save the beverages and greens for after your main course. 

Make sure to include foods that have a mix of protein, fiber and healthy fats in every meal to help keep your blood sugar even. Skip sugary drinks with empty nutritional value and processed and highly refined foods like white bread, chips and cookies, and load up on calories that benefit you and your baby (like whole wheat bread, kale and walnuts).

Eat more often

Try not to skip meals, even if you’re feeling nauseous. Instead of eating three large meals a day, try having six smaller snack-sized bites every two hours or so. Eating smaller, frequent meals also helps combat morning sickness. 

Don't feel like eating? Make yourself a thick smoothie and fortify it with wheat germ. 

Compensate for exercise

Have a regular exercise routine? Exercise during pregnancy is excellent for your health and your baby’s in most cases, especially when done in moderation and under your doctor’s guidance. Just make sure you’re eating enough to hit your fitness and caloric goals.

To make up for a sweat session, eat a nutrient-dense snack around the time you exercise or follow the workout with a calorie-packed protein shake. It’s especially important if your workout involves high-intensity exercise or lasts longer than 45 minutes.

According to the Centers for Disease Control and Prevention (CDC), if you start your pregnancy underweight you should work up to or maintain at least 150 minutes of moderate intensity aerobic activity (such as brisk walking) per week. Talk to your doctor to see if you have any physical activity restrictions.

When to see the doctor

Sometimes, severe and continuous nausea and vomiting can keep you from gaining weight during pregnancy. If you’re among the 1 to 3% of women who develop hyperemesis gravidarum, your baby may not be getting the vital nutrients and vitamins he needs to grow. You may also be dehydrated, which can be a problem for both you and your baby. 

Be sure to let your doctor know if your morning sickness is severe. Signs of hyperemesis gravidarum include not being able to keep food or liquids down and losing weight. Your practitioner may prescribe lifestyle changes or medication to help you manage the condition.

Finally, if you’ve struggled with an eating disorder or body image issues in the past, pregnancy weight gain can be challenging, and regular weigh-ins can trigger anxiety. Speak honestly with your practitioner about past or present disordered eating. Your doctor may recommend that you see a registered dietitian who is qualified to design diets to treat specific medical conditions.

Try to keep in mind that gaining weight is essential for your baby’s growth and health, and your team is there to answer any questions, provide guidance and help you get over any hurdles.