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Reproductive Health

The Ultimate Guide to Pregnancy Weight Gain

by DR. LORIANA SOMA, EXPERT OB/GYN

pregnant woman cradling belly in green dress whiile walking outside

Eating during pregnancy can often be fraught with worry. Women wonder if they are overeating, or not eating enough. They crave carbs but know they should eat vegetables. Is a tuna sandwich ok? What about a cup of coffee? How much is too much weight to gain? 

While so much of pregnancy is unknown, nutrition and healthy weight gain are a part of pregnancy that women can affect with their actions. Poor diet or excessive weight gain can cause pregnancy complications, so women need to have the education necessary to make smart decisions. 

So, how much should you eat?

Let’s start with the basics. How much should a pregnant woman be eating before pregnancy, and during each trimester?

Pre-conception

You might not realize it, but you can impact your future baby’s health before you even get pregnant! Exercising regularly, eating a nutritious, balanced diet, and taking a prenatal vitamin with at least 400mcg of folic acid can help your future pregnancy.        

First Trimester

The first trimester is usually marked with the dreaded morning sickness. Despite the name, food aversions, nausea, or vomiting can affect women throughout the day, not just in the morning. Many women will not gain weight during this time, but small, frequent meals can help fight nausea, and it’s very important to stay well hydrated.

photo of craker box with crackers spilled around

If my patients are having trouble keeping down food, I recommend they eat whatever sounds good, even if it’s somewhat unhealthy (in moderation!). Bland foods are generally well tolerated, like rice, crackers, or toast. Small meals and snacks every 2-3 hours will help avoid an empty stomach which can lead to nausea. Eating crackers, dry toast, or dry cereal before getting out of bed can help in the mornings. Other home nausea remedies include ginger supplements or chews and acupressure bracelets. Over the counter medications include vitamin B6 and unisom (a sleep aid). A combination of vitamin B6 and doxylamine (the active ingredient in Unisom®) is also available as a prescription drug called Diclegis®. Additionally, your doctor can prescribe stronger nausea medicine if needed. 

The good news is, the fetus can develop without a perfectly balanced diet in the first trimester. So focus on caring for yourself and listening to what your body needs. 

yogurt parfait

Second & Third Trimesters           

After the first trimester, morning sickness generally subsides, and a woman should begin to increase her caloric intake. In the second trimester, the average intake should increase by about 300-450 calories a day. By the third trimester, this should be at the top end of the range, about 450 calories per day. This extra amount of calories translates to a weight gain of about a pound a week. Women pregnant with twins should increase their intake by about 600 calories a day and expect to gain about 1.5 pounds a week.

We’ve all heard the adage of “eating for two”, but that’s not really the case. 300-450 calories translate to a couple of healthy snacks per day, like greek yogurt with berries and nuts, or a few slices of avocado on rice cakes. Overall, women should try to eat fruits and veggies, whole grains, and a variety of protein, like low-fat dairy. 

What’s a normal amount of weight gain during pregnancy? 

Each woman will have a personalized recommended amount of weight gain based on her pre-pregnancy weight and BMI. This topic should be discussed with her doctor throughout her pregnancy.  

But first, let’s break down the total weight gain of pregnancy. While your body does store more fat and protein (to the tune of 8-10 pounds), the weight comes from different places. 

Baby6-8 pounds
Breasts1-2 pounds
Placenta1-2 pounds
Uterus1-2 pounds
Amniotic Fluid2-3 pounds
Blood3-4 pounds
Fluids3-4 pounds
Protein & fat8-10 pounds
Total Weight Gain25-35 pounds

The Institute of Medicine has made the following recommendations for pregnancy:

Weight CategoryTotal Weight GainRates of Gain after 1st Trimester
Underweight
(<18.5 BMI)
28-40lb1 pound/week
Normal Weight
(18.5-24.9 BMI)
25-35lb1 pound/week
Overweight
(25-29.9 BMI)
15-25lb0.6 pound/week
Obese
(>30 BMI)
11-20lb0.5 pound/week

Pregnant women are weighed at each prenatal visit, so their doctors can follow their weight gain and help them stay on track. If the mother’s weight gain is far under or over the general expectation, the doctor can perform a growth ultrasound. This ultrasound estimates the fetal weight and makes sure the baby is developing properly.

What are the risks of too much weight gain during pregnancy?

You do not want to be dieting during pregnancy, but keeping a healthy eye on weight gain can help avoid a range of complications. Gestational diabetes, difficulties during labor, c-section wound infections, as well as postpartum obesity, can all come from too much weight gain.

tuna sushi rolls not for pregnant women

The Pregnancy Eating Guidelines

There are a few foods pregnant women should avoid for safety reasons. Below is a list of the most common food questions pregnant women have.

Are there certain foods pregnant women should avoid?

To reduce exposure to unwanted bacteria and parasites, pregnant women should avoid:

  • Raw fish, like sushi or smoked salmon
  • Undercooked meats
  • Cold deli meats, cold hot dogs (these can be consumed if heated to steaming hot)
  • Raw eggs
  • Unpasteurized cheeses
  • Unpasteurized juices
  • Raw sprouts 

Can I drink coffee?

Yes! But I recommended limiting your intake to less than 200mg/day. How does that break down?

  • One 8oz cup of brewed coffee has 100-200mg of caffeine (Keep in mind, a “tall” at Starbucks is 12oz!). 
  • 1oz espresso 30-90mg
  • 8oz tea 40-120mg

Can I maintain my vegetarian diet?

Yes, as long as you maintain a well-balanced diet.

Fish: What can I eat? And how much is ok?

The general rule is that 2-3 servings of low mercury fish are safe. The FDA has a comprehensive guide to best choices that you can check out, but here is a guide to the most common fish.

  • Best choices: cod, salmon, tilapia, tuna, trout, and shellfish like shrimp, oysters, and clams 
  • Avoid high mercury fish: swordfish, king mackerel, shark and orange roughy

If I change my diet, can I prevent my child from having food allergies?

There is no strong evidence that avoiding any foods during pregnancy will prevent childhood allergies. However, there is some evidence that breastfeeding can help reduce allergies in children. 

Can I take herbal supplements?

Herbal supplements are not required to go through FDA approval, and therefore are not studied for safety in pregnant women. Supplements, other than prenatal vitamins, are not recommended because we can’t say for sure if they are safe or not. 

As always, speak to your doctor about your particular nutritional needs during pregnancy. Some medical conditions or special diets may require further consultation or supplements.  

REFERENCES

American College of Obstetricians and Gynecologists. Weight gain during pregnancy. Committee Opinion number 538. January, 2013.