When Do You Start Gaining Weight In Pregnancy?

“Weight gain during pregnancy is a natural and expected part of the process, and it usually starts to occur during the first trimester, which is the first 12 weeks of pregnancy,” Dr. Michael Green, OB/Gyn at Winona Health, in Winona, Minnesota, told Mom.com “The average weight gain in the first trimester is around 2-4 pounds, although some women may not gain any weight during this time.”

Dr. Green added that the rate of weight gain tends to change as pregnancy progresses. He said that the average weight gain during the second trimester (weeks 13-27), is around 1-2 pounds per week. And that it slows down again during the third trimester (weeks 28-40), generally to around one pound per week.

“It's important to note that these are averages and that every pregnancy is different,” Dr. Green said.

Crystal Young would agree with that. The Sacramento area mother of two remembers being surprised at how quickly she gained weight during her first pregnancy.

“I think one of my biggest things I remember was when I first got pregnant was how much weight I gained really fast. Even though I didn’t have a belly,” she told Mom.com.

“Not a lot of people talk about that very much, but they say oh, you’re gonna gain between 15 and 30 pounds, 30 or 40 pounds is like average for most people," Young said. "And I was like a pretty normal weight. I would say I had maybe 10 extra pounds on me than normal. And I ended up gaining 60 with my first and 40 with my second.”

Crystal said her doctor was not concerned about her weight gain because she’s tall, and comes from a family with a history of birthing big babies.

“Both of my kids were like 10 pounds, 10 ounces and 10 pounds, 11 ounces, and the first was 22 and a half inches long, and they were both a week late,” she told Mom.com.

Dr. Green points out circumstances to consider when talking about pregnancy weight gain. “The total weight gain during pregnancy depends on many factors, such as pre-pregnancy weight, height, and muscle mass," he said. "It's also important to note that weight gain during pregnancy is not only due to the baby's growth but also due to the increase in blood volume, amniotic fluid, and the development of the placenta.”

Determining a target weight for any individual pregnant person is a little bit like Goldilocks and the Three Bears: what is too much or too little for one person may be just right for another. A person pregnant with multiples will need to consume even more calories to support the babies’ growth. That’s why it’s tough to find a pregnancy weight gain chart that drills down on what you should be gaining by week.

The CDC offers guidelines and trackers for average pregnancy weight, based on an individual’s BMI — but BMI is just a tool, and can be a flawed one, at that. You can also use an online pregnancy weight calculator to keep track of your weight gain, but again, this is for basic reference and doesn't encompass all circumstances.

This is why it’s imperative to communicate with your health care providers about what you are experiencing in your individual pregnancy. In turn, they can holistically help you navigate all the issues that may be affecting your pregnancy weight gain.

“Healthy weight gain in pregnancy should be slow and steady,” OB/GYN Dr. Greg Marchand told Mom.com

You might wonder, is it safe to lose weight while pregnant?

“You want to avoid losing weight in pregnancy to be sure that your body is not competing with your baby for nutrition," Dr. Marchand advised. "How much weight you need to gain will depend on how your weight is when you first become pregnant. Women who are underweight need to gain the most (around 30 pounds,) and obese women need to gain the least (often just maintain their weight.) At any rate, a good goal is gaining around one pound every 2-3 weeks, and you never want to gain more than a pound a week. In the US about half of women gain too much weight during pregnancy.”

The Mayo Clinic explains that it’s important to monitor your weight gain because too much could result in complications such as diabetes, high blood pressure, and preeclampsia. And gaining too little can produce a low birthweight baby with serious health problems of her own.

“Contrary to popular belief, you do not have to eat for two," Nutritionist Eva de Angelis told Mom.com. "During the second and third trimesters, you only need to increase your calorie intake by about 300 calories per day. Despite this, I strongly advise you to consult with your doctor about specific nutritional needs and individual weight gain charts.”

De Angelis had suggestions for maintaining a healthy pregnancy weight. “When pregnant, the same basic principles of healthy eating apply: eat plenty of fresh fruits and vegetables to ensure tons of minerals, vitamins, and fiber; choose whole grains and their products over refined grains; stick to low-fat dairy products like low-fat milk and plain Greek yogurt; pick good quality protein sources like lean meats and pulses; and add nuts, seeds, and oils for healthy fats.”

Moderate exercise can help temper weight gain, keep you comfortable, and prepare your body for the actual birth.

Crystal told Mom.com that the number one thing is to just take care of yourself.

“Just remember that this is a miracle, just building a baby. Don’t put so much pressure on yourself. Eat healthy, go on walks, and do whatever makes you feel good,” she said.