Evidence Based

What to Know About Weight Gain During Pregnancy

Kathy Shattler, MS, RDN

Published at 01:30

Weight gain during pregnancy is natural. Photo: Alexandra Morosanu/shutterstock

Pregnancy is one of the most important times in a woman’s life, influencing the lifelong health of the developing fetus into adulthood. Both under and over-nutrition can impact the size[1] and body composition of the baby at birth, with metabolic changes lasting a lifetime.

Weight gain during pregnancy is an important consideration that should start when you discover you have conceived. The nutrients and calories you provide your developing baby may affect its risk for cardiovascular disease or metabolic disorders later in life.

A healthy diet during pregnancy should contain a mixture of all food groups, such as dairy, lean proteins, vegetables and fruits, whole grains, and healthy fats. Processed foods, foods high in salt and sugar, and refined grains should be minimized. Following a balanced diet will help you manage your weight gain.

So, sit back and learn to relax during your pregnancy as we cover those burning questions about your weight gain. Knowledge is power and gives you the skills you need to feel confident that you can manage your stressors, such as weight gain.

What to Know About Weight Gain During Pregnancy

  • The recommended amount of weight gain is based on the woman’s pre-pregnancy BMI.
  • The usual weight gain for a singleton pregnancy ranges between 22 and 28 pounds.
  •  Most of this weight gain occurs after week 20.
  •  While many pregnant women restrict calories, hoping that they will not gain too much weight, getting enough calories is essential to the proper development of the fetus. 
  • Most experts do not recommend weight loss during pregnancy.
  • About 48% gain too much weight during pregnancy.

Weight Gain During Pregnancy: How Much Is Normal?

Weight Gain During Pregnancy
Weight Gain During Pregnancy. Photo: Alexander_Safonov/shutterstock

Weight gain during pregnancy is based on body mass index[2]. Despite the CDC guidelines, most women gain between 22 and 28 pounds[3] during pregnancy, with most of the weight gain occurring after week 20. So, how much weight should you gain?

Table 1. CDC Weight Gain Recommendations for Women Carrying One Baby

If you had this BMI before pregnancyYou should gain this much weight.
BMI less than 18.5 (underweight)              28-40 pounds total
BMI 18.5-24.9 (normal weight)              25-35 pounds total
BMI 25.0-29.0 (overweight)              15-25 pounds total
BMI greater than or equal to 30.0 (obese)              11-20 pounds total

Table 2. CDC Weight Gain Recommendations for Women Carrying Twins

If you had this BMI before pregnancyYou should gain this much weight.
BMI less than 18.5               50-62 pounds total
BMI 18.5-24.9              37-54 pounds total
BMI 25.0-29.0              31-50 pounds total
BMI greater than 30.0              25-42 pounds total
The metabolic rate in a twin pregnancy is 10% higher[4] than in a singleton pregnancy, so calories must be calculated at approximately 40% higher. And, of course, expected weight gain is more. Note, however, that expected weight gain is not doubled from a singleton pregnancy because you are carrying two babies.

If you don’t know your body mass index, plenty of online calculators will give you your value in a matter of seconds. Simply plug in your height and weight.

What’s Causing The Weight Gain?

You are gaining weight to support placental tissue, amniotic fluid, a growing uterus, larger breasts, a baby’s growing tissues and organs, and some extra body fat to support lactation after birth.

The approximate distribution[5] of your weight gain is as follows:

  • Baby weight: 8 pounds.
  • Placental tissue: 2-3 pounds.
  • Amniotic fluid: 2-3 pounds.
  • Breast tissue: 2-3 pounds.
  • Blood supply: 4 pounds.
  • Fat stores: 5-9 pounds.
  • Uterus growth: 2-5 pounds.

Although a baby bump might begin showing between 12 and 16 weeks, you shouldn’t expect to see weight gain in the first 12 weeks. Some women do experience more severe cases of nausea and vomiting that may cause some loss of weight in the first trimester, but such weight loss is not healthy or desired.
You might wonder why you are so hungry during this time in your life. Your body knows it needs extra fuel, increasing your appetite and, thus, calorie intake. Other reasons include consuming too many liquids and not enough food, not chewing well enough, cravings, and growth spurts in your baby’s development.

Is It Safe To Lose Weight When Pregnant?

If you are obese or overweight during your pregnancy, you may wonder about losing a little weight with your increased calorie requirements. However, the literature does not support the safety of weight loss[6] during pregnancy.

Weight loss while pregnant increases the risk[7] of preterm delivery and small-for-gestational-age babies. Other complications may also arise, such as low amniotic fluid, pregnancy-induced hypertension, or preeclampsia.

Low birth weight babies have a higher risk[8] of mortality, physical and cognitive delays or disabilities, and chronic health problems later in life. They are 20 times as likely to have complications before or after birth and to suffer from post-partum illness.
Historical data concluded that severe restrictions in food intake[9] leading to weight loss, such as those found in eating disordered patients or victims of famine, may lead to infant diabetes, coronary artery disease, breast cancer, or metabolic syndrome.

Managing Weight During Pregnancy

Managing Weight During Pregnancy
Managing Weight During Pregnancy. Photo: SofikoS/shutterstock

The CDC reports that only one-third of pregnant women[10] gain the recommended weight according to the guidelines. Furthermore, 21% gain too little weight, while 48% gain too much weight. The primary problem with weight management during this critical phase in life is overeating too many calories.

Overweight women should limit their weekly weight gain[11] in the second and third trimesters to 0.5-0.7 lbs. per week, and obese women should limit weekly weight gain during the same time period to 0.4-0.6 lbs. per week. It is wise to weigh yourself regularly early in the morning, with the same scales, preferably digital, every week and keep a record.

You should strive to get the proper number of calories for your situation. Keep a food journal with calorie equivalents to determine your daily calorie intake. Use the tips in this guide to know your calorie goals before you start keeping your journal.
Many free online calculators will provide you with your pre-pregnancy calorie needs. You then add the recommended daily calories for your trimester to your pre-pregnancy maintenance needs provided by the calculator. To determine your menu composition, use the Dietary Guidelines 2025[12] for the recommended servings from each food group for your designated calorie level.

How Many Calories Should You Eat For Two?

Your grandmother used to advise young mothers to eat for two. If you eat for two, you will gain far too much weight. The number of calories you eat to maintain weight should stay the same in the first trimester. If you started out at a normal weight, you can increase your calories in the second and third trimesters as outlined below.

Your weight gain should come from additional calories eaten[13] during each trimester from a balanced diet containing foods from all the food groups. 

In the first trimester, you focus on maintaining your weight, and no calorie increase is needed. During the second trimester of a singleton pregnancy, you should add about 340 more daily calories to your maintenance pre-pregnancy value. And finally, in the third trimester, when you gain the most weight, you should increase your calories by 452 per day.

When You’re Overweight

If you start your pregnancy journey overweight, you will want to limit your weight gain and calories, not nutrients. You must eat fewer calories per day in your second and third trimesters than your normal-weight counterparts to avoid excess weight gain. Being overweight increases your risk[14] for miscarriage, high blood pressure, preeclampsia, gestational diabetes, blood clots and delivery complications.

Eating fewer calories approximates 250 calories above your maintenance caloric level for the second trimester and about 300 calories for the third trimester. Monitoring your weekly weight is the best way to tell whether you are overeating calories; make adjustments based on what the scale tells you. If you gained too much in one week, you know you ate too many calories that week.

One pound of weight gain per week is about 500 calories extra per day; one-half pound of body weight gain is about 250 extra calories per day; one-fourth pound extra weight gain is about 125 extra calories per day. Adjust your calories by your excess weight gain to plan for next week’s calorie intake goal and follow the weight gain guidelines in this article.

Note that while we provide general guidelines to help you start your weight management program, everybody is different, and calorie needs vary based on age, BMI, activity, and metabolic rate.

You can decrease your calories by choosing

  • Low-fat dairy.
  • Lean Proteins: Cut the fat off of meat. Chill stews and soups and skim the fat off the top. When eating poultry, choose white meat over dark and remove the skin.
  • High fiber options such as whole grains rather than refined.
  • Water over juices, energy drinks, and sodas.
  • Unprocessed foods and healthy snacks.
  • Fresh vegetables and fruits over canned, processed, or dried.
  • Healthy fats that are high in metabolism-boosting monounsaturated fats, such as avocado.
  • Lower fat meals such as stir-fry rather than deep fried. 
  • Low glycemic options; avoid sugar.

When You’re Underweight

Some people find it hard to gain weight no matter what they do. Such individuals must focus on nutrient and calorie-dense foods that fuel the body without increasing satiety or blood sugar.

To increase calories in your diet

  • Combine carbohydrates with fats. Examples are graham crackers and nut butter, apples with peanut butter, and rice-stuffed avocados.
  • Eat small, frequent meals that are calorically dense.
  • Consume nuts throughout the day.
  • Add a daily avocado, but start slow since they are fiber-rich.
  • Eat brown rice more frequently as it is a calorically dense grain.
  • Choose more significant portions at mealtime or opt for seconds.
  • Add dry milk or liquid milk to mashed potatoes or other dishes.
  • Add extra olive oil or canola oil to your cooking.
  • Drink smoothies and shakes.
  • Add extra cheese to recipes.

Why Is It Important to Gain Weight During Pregnancy?

Weight gain is necessary to support your growing baby’s body tissues and organs. Gaining weight helps build placental and breast tissue, and it reduces complications.

If you don’t gain enough weight, you risk having a baby[15] that is too small, which is called small for gestational age. These babies have more trouble initiating breastfeeding, may be at increased risk for infectious diseases, and may experience delays in developmental growth.
 Research has pointed to autism risks related to pregnancy, premature birth being one of them. While gaining inadequate weight has its own risks, excessive weight gain can lead to prematurity and, thus, autism.

Exercising While Pregnant

You can manage weight effectively with lifestyle changes in dietary choices and safe exercise options. For weight control during pregnancy, the CDC recommends 150 minutes a week[16] of walking, swimming, yoga, pilates, or stationary bike riding. Such an exercise regime may prevent gestational diabetes, depression, and excessive weight gain.

Conclusion

Pregnancy is a time of change and transformation where healthy weight gain is expected and essential to a birthing experience free of complications. Managing one’s calorie and nutrient intake during this time is crucial for proper fetal development and growth. Both gaining too much weight and too little can lead to unintended consequences for you and your baby; following the tips in this guide should help you gain the confidence you need to meet your weight goals.

Frequently Asked Questions

Can I drink an energy drink while pregnant?

No, energy drinks may contain unsafe ingredients such as too much sugar, artificial sweeteners or questionable herbs. A typical energy drink may contain up to 30 grams of sugar[17].

What trimester do you gain the most weight in?

The third trimester.

How much total weight can I gain if I am having twins?

The CDC has a chart on acceptable weight[18] gain during pregnancy based on your pre-pregnancy BMI.

Can I still exercise?

Yes, but make wise choices. Safe exercises include walking, swimming, riding a stationary bike, pilates, and yoga.

Kathy Shattler, a Registered Dietitian for over 25 years, operates a Telehealth Clinic and freelances as a writer. Holding a Master’s in Human Nutrition from Michigan State University, her expertise spans clinical nutrition and public health. Recognized as a pioneer in her field, Kathy continually pursues excellence in integrative medicine public health education, and her writing endeavors.

Resources

MANA adheres to strict sourcing guidelines, avoids most tertiary sources, and uses only professional resources updated to contain accurate and current information. We majorly rely on peer-reviewed studies, academic research from reputable medical associations. For more information regarding our editorial process, please refer to the provided resources.

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