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Are you worried you're gaining too much or not enough weight? Do you think your weight gain rate may be considerably faster than it should? Let's dispel all the doubts you may have, one by one! ⚖️

💡 This article is a part of a bigger series, based on our pregnancy weight gain calculator.

How much weight should I gain during pregnancy?

Your weight gain during pregnancy is based on your weight before pregnancy, as well as the number of babies growing inside your womb. Remember that there is no ideal amount of weight a woman should gain during her pregnancy — as most things connected to your body, it's unique to you. However, we should never take things to their extremes! Avoid gaining too much or too little weight; both obesity and being far underweight can cause multiple serious problems throughout your pregnancy and put your baby's life at risk.

Take a look at the recommended amount of weight for different pre-pregnancy weights and BMI (calculated with your weight and height):

  • Underweight (BMI <18.5)
    It's recommended to gain 28 to 40 pounds (12.7–18.1 kg)
  • Normal (BMI 18.5–24.9)
    • Single pregnancy: it's recommended to gain 25 to 35 pounds (11.3–15.9 kg)
    • Twin pregnancy expected weight gain: 37–54 pounds (16.8–24.5 kg)
  • Overweight (BMI between 25 and 29.9)
    • Single pregnancy: it's recommended to gain 15 to 25 pounds (6.8–11.3 kg)
    • Twin pregnancy expected weight gain: 14-50 pounds (16.8–22.7 kg)
  • Obese (BMI over 30)
    • Single pregnancy: it's recommended to gain 11 to 20 pounds (5–9 kg)
    • Twin pregnancy expected weight gain: 25–42 pounds (11.3–19 kg)

You can easily calculate your pre-pregnancy BMI with a simple equation:

BMI=weight [kg](height [m])2\text{BMI} = \frac{ \text{weight [kg]} }{ (\text{height [m]})^2 }

...or you can use one of our BMI calculators for women.

❗ Remember - BMI doesn't apply to women who are already pregnant.

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

Sometimes gaining a few extra pounds during pregnancy is easier than we wish it would be. 🍩 That's why it's essential to successfully identify and eliminate risks of excessive weight gain in pregnant women — overweight and obese patients have a much higher chance of stillbirth and other severe complications!

Let's list all the risks one by one. For each risk, we'll give you tips for maintaining a healthy pregnancy weight:

  • Eating for two. 👯

    In reality, your daily intake of calories should increase only by 300 kcal, starting at the beginning of the second trimester.

  • Choosing calorie-dense meals, such as fast foods or sweets.

    You should replace them with healthier alternatives such as nuts, fruits, and veggies.

  • Being overweight or obese before the pregnancy.

    Ladies with higher pre-pregnancy weight need to gain less during the gestation than the underweight or average ones. To control your weight gain, it is best to remain active, preferably by walking and doing some moderate or aerobic exercises.

  • Comorbidities (such as polycystic ovary syndrome or hypothyroidism) may play a role in excessive weight gain during pregnancy or worse diets results.

    Diagnosing and treating these diseases may be crucial for your own and your baby's well-being.

When should I see my doctor about pregnancy weight gain?

Your medical practitioner (doctor or midwife) should check your weight during every appointment, roughly every 4–5 weeks. This way, you'll be able to monitor your weight and its changes throughout the entire pregnancy. Regular check-ups let you act quickly if you're gaining more or less than the recommended weight gain range. ⏰

If you wish to monitor your weight even further, you can easily weigh yourself every day. Make sure to do this at the same time of the day, before having your meal. Consult your medical practitioner if you gain more than 0.5 kg (1.1 lb) per week or if you're suddenly losing or gaining a lot of weight, especially later in pregnancy.

Remember — gaining too much or too little weight in pregnancy can both increase the risk of serious complications!

What is considered rapid weight gain?

The rate of weight gain varies a lot and is pretty individual, and you shouldn't compare yourself with other pregnant women. Most importantly, remember not to judge yourself for gaining too much or too little weight based solely on someone else's opinion.

The amount of weight gain during pregnancy depends on the trimester — the greatest increase is noted between the 20th and 30th week of gestation (see: gestational age). Generally speaking, there are a few red flags that you should pay attention to. Book an appointment with your OB-GYN if:

  • You gained weight too suddenly;
  • You're gaining more than 0.5kg (1.1 lb) per week; or
  • The weight gain is accompanied with elevated blood pressure.

Where does the extra weight go during pregnancy?

Pregnancy is truly a miracle. Your body is turning into a superhero, a machine capable of amazing things. As all important changes, the pregnancy needs its time, place, and — there's no denying it — extra weight to house all those additional functions. 🤰

Your weight gain in pregnancy doesn't come only from the growing new life — this complicated factory needs both the supplies (fat tissue) and tools (enlarged breast and uterus).

What are the supplies?

Most pregnancy hormones are based on cholesterol, a substance accumulated in fat tissue. A certain amount of fat is therefore essential for the pregnancy to survive.

As for tools, the uterus is probably the most important one of them. It houses the baby for the entire 9 months, and increases its weight from 50 g (1.8 oz) to almost 1 kg (2.2 lb)! The volume of your blood increases as well, by nearly 50% — the same thing happens to other fluids accumulated in your body. It all helps the baby receive all the substances it needs.

As you can see, there's nothing wrong with gaining more weight during pregnancy — Mother Nature created it this way!

💡 If you'd like to see the entire list of additional pounds women gain during gestation, don't hesitate to check the How to maintain weight in pregnancy calculator's article.

Does watching your weight prevent stretch marks?

Yes — if you avoid excessive weight gain, you can lower the possibility of stretch marks appearing on your skin. Moderate exercise during pregnancy may help you achieve that goal, as maintaining physical activity is the key for a healthy weight gain. This way, you'll be able to decrease the amount of unnecessary fat tissue and reduce the stretching forces that apply to your skin.

However, you shouldn't forget to take proper care of your skin: hydrate and oil it as often as it needs. 🚰 A protective routine should start even before the pregnancy itself. If your skin is in good condition, it has better chances to successfully endure all the greatest challenges during the second and third trimester of the pregnancy.

PS: Don't forget to drink plenty of water!

Łucja Zaborowska, MD, PhD candidate
Before pregnancy
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Weight during pregnancy
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