BMI During Pregnancy: What’s Healthy Weight Gain? Find Out!

Why is Gaining Weight During Pregnancy Normal?

The weight you gain during pregnancy directly impacts the current and future health of the expectant mother and the baby. It helps in the fetus’s development and keeps the overall pregnancy journey healthy & stable. A healthy pregnancy weight gain is due to factors such as the fetus's weight, placenta, amniotic fluid, and increased blood volume.

How are BMI and Pregnancy Weight Gain Related?

Now, the question is, what is the normal weight of a pregnant woman? Your BMI before pregnancy is directly related to what should be your normal weight (in kgs) as a pregnant woman.

To calculate healthy weight gain during pregnancy, you can use the following BMI formula: BMI = weight (kg) ÷ height (m²)

Compare this BMI value with the pregnancy weight gain chart by week to calculate your ideal increased weight. Using a BMI calculator during pregnancy can be extremely helpful to keep track of your weight and ensure you achieve the best possible pregnancy outcomes.

What is the Ideal Weight Gain During Pregnancy?

Recommended weight gain in pregnancy is determined by pre-pregnancy weight. Use the following chart to monitor your pregnancy weight gain for a single baby:

Pre-pregnancy BMI

Recommended Weight Gain During Pregnancy (in kgs)

Underweight (BMI less than 18.5)

12.5-18

Normal weight (BMI between 18.5 and 24.9)

11.5-16

Overweight (BMI between 25 and 29.9)

7-11.5

Obese - all classes (BMI 30 or greater)

5-9

The weight gain also differs depending on the trimester you are in. Usually, for the first trimester, no or little weight gain of about 1-2 kgs is considered normal. Here is the general idea for the normal weight gain during pregnancy per trimester:

Pre-pregnancy BMI

Recommended Weight Gain per Month in 2nd and 3rd Trimester

Underweight (BMI less than 18.5)

2-2.6

Normal weight (BMI between 18.5 and 24.9)

1.5-2.3

Overweight (BMI between 25 and 29.9)

1-1.5

Obese - all classes (BMI 30 or greater)

0.8-1.2

Weight Gain in Pregnancy: Normal vs Not Normal and Its Side Effects

As a pregnant woman, it is essential to monitor your weight gain monthly. If you are witnessing weight gain more or less than usual, you must consult your gynaecologist. It is essential to remember that neither excessive nor inadequate weight gain is recommended. They can have adverse effects on the expectant mother and the baby, leading to severe health risks. Although maternity insurance can take care of the financial burden, it cannot mitigate the health complications.

What’s Normal?

Gaining weight is normal.

The ideal weight gain during pregnancy is 11-16 kg for a woman with a normal BMI and carrying a single child.

For a normal-weight pregnant woman carrying twins or multiples, the average weight gain differs and should be discussed with the doctor.

What’s Not Normal?

Gaining too little weight is not normal.

Gaining excessive weight is not recommended.

Inadequate weight increases the risk of pregnancy complications.

What Happens if You Gain Excessive Weight During Pregnancy?

Excessive pregnancy weight gain can result in the following complications for the mother or the baby:

Pre-eclampsia; a serious health issue due to high BP, leading to potential organ damage

Stillbirth risks

Macrosomia; the baby is likely to be above the average weight

Gestational diabetes; a temporary type of diabetes

High risk of C-section

Prolonged and difficult labour

Sleep Apnea

Causes difficulty losing weight after delivery

Pre-term birth

What Happens if You Gain Insufficient Weight During Pregnancy?

Low maternal weight gain can lead to the following complications:

Miscarriage

Affects breast milk production

Health problems like anemia

Intrauterine growth restriction (where the baby’s growth is significantly restricted)

Higher risk of preterm birth

Fetal malnutrition

Low birth weight

How to Maintain a Healthy BMI During Pregnancy?

Maintaining a healthy weight throughout pregnancy is crucial for a smooth delivery and baby’s adequate development. The first step in ensuring a healthy BMI during pregnancy is to know and keep track of your BMI and calorie needs.

To ensure you gain a healthy weight during your maternity, follow the tips below:

Eat a balanced diet rich in protein, fibre, vitamins, minerals and healthy fats

Add fresh fruits and vegetables to your diet

Eat small and frequent meals

Add high-calorie snacks to your diet, such as nuts, dried fruits, cheese, yogurt, etc.

Drink adequate water to ensure good placenta health

Limit processed food and sugary drinks

Check folic acid, iron, calcium and iodine levels

Stay physically active through low or moderate-intensity activities

Ensure sufficient rest and sleep

Avoid mental stress

Stay in regular touch with your gynecologist

FAQs

Q1. What is an unhealthy BMI for pregnancy?

Ans: An unhealthy BMI for pregnancy is if the expectant mother falls in the category of underweight (BMI < 18.5) or is overweight or obese (BMI > 25). You can download the PDF of the pregnancy weight gain chart by week to keep a tab on the weight you must gain throughout the maternity period.
Q2. Is BMI calculated differently when pregnant?

Ans: No. The BMI formula remains the same for calculation when pregnant. The BMI is always calculated by dividing weight (in kilograms) by the square height (in meters). However, the purpose of BMI changes in pregnancy as it is used to recommend the ideal weight gain throughout pregnancy.
Q3. What is the significance of BMI in pregnancy?

Ans: BMI is significant in the pregnancy journey because it guides the ideal weight for a pregnant woman. Keeping a tab on BMI values across different stages helps to monitor weight gain during pregnancy month by month.
Q4. What is a healthy BMI to get pregnant?

Ans: The normal weight of a pregnant woman varies depending on her pre-pregnancy BMI. The healthy BMI for conceiving smoothly is between 18.5 and 24.9.
Q5. What BMI causes a high-risk pregnancy?

Ans: A BMI of less than 18.5 or above 30 can cause a high-risk pregnancy. This is because both being underweight and being overweight can cause pregnancy-related complications. Hence, you must be worried about your pregnancy only if you fall into the underweight or obese category.
Q6. Can you give birth naturally with a high BMI?

Ans: Yes. You can give birth naturally even with a high BMI. However, women with a high BMI are at an increased risk of cesarean deliveries, prolonged labour or delivery-related complications.
Q7. Is it normal to gain 20 kg during pregnancy?

Ans: Gaining a weight of 20kgs during pregnancy can be classified as normal or excessive, depending on what your pre-pregnancy weight is. It also depends on whether you are carrying a single child or multiples.
Q8. In which trimester do I gain the most weight?

Ans: The most rapid and significant weight gain happens in the third trimester.
Q9. What are the signs of unhealthy weight gain during pregnancy?

Ans: Signs of unhealthy weight gain include excessive swelling (especially in hands, legs or face), upper abdominal pain, nausea, breathlessness, severe headaches and sleep apnea.

BMI During Pregnancy: What's Healthy Weight Gain?

FAQs

Q1. What is an unhealthy BMI for pregnancy?

Q2. Is BMI calculated differently when pregnant?

Q3. What is the significance of BMI in pregnancy?

Q4. What is a healthy BMI to get pregnant?

Q5. What BMI causes a high-risk pregnancy?

Q6. Can you give birth naturally with a high BMI?

Q7. Is it normal to gain 20 kg during pregnancy?

Q8. In which trimester do I gain the most weight?

Q9. What are the signs of unhealthy weight gain during pregnancy?