BMI (Body Mass Index) During Pregnancy

BMI (Body Mass Index) During Pregnancy

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Pregnancy is not an easy journey. As the pregnancy progresses, there is always a risk of certain complications but not all women will face problems. However, if you are obese or are on the heavier side, you might face certain complications during pregnancy or while giving birth to your baby. Understanding the normal BMI for pregnancy is absolutely necessary since the onset of obesity directly increases the chances of having an unhealthy heavy baby, or leading to choose a caesarean delivery over a normal one.





What Is Body Mass Index (BMI)?

The concept of BMI has existed in the space of healthcare and medical sciences for many years. Recently, it has found recognition in the mainstream and is being hailed as a great standard to understand your position in health. BMI is a simple mathematical formula that makes use of various parameters to get to a medical understanding of your weight, demarcated either as underweight, normal, or overweight. As the name ‘body mass index’ suggests, the BMI score is used to figure out if you have the right proportion of body fat based on your height and weight. A simple formula to calculate the score is to divide your weight in kgs by the square of your height in cms.

BMI formula

Is BMI an Accurate Indicator of Good Health

Even though BMI is used pretty widely nowadays, it doesn’t exactly indicate your health condition. As per a recent study, the BMI score of certain people was compared with the actual values of various other health markers such as blood pressure, cholesterol, sugar levels etc. and it was observed that many people who were healthy on those lines were termed as overweight as per the BMI score. On the other hand, others with good BMI scores were detected to have various health issues in other areas.




The body shapes of people across the world differ in the physical structure and in muscle composition, making it difficult to differentiate simple fat from muscle using a mathematical formula. The technologies of today have made it possible to get over that gap and reach a conclusion of higher accuracy. Taking into account the waist to height ratio instead gives a better idea of the health of the person since a lot of excess fat tends to get deposited in the region of the waist, around the important organs such as kidneys, liver, and heart.

BMI and Weight Gain Range in Pregnancy

To get a better understanding of what might be your current health status based on your BMI score, as well as to get a better hang of the weight gain during your pregnancy that can be considered as healthy, we have put together a BMI pregnancy weight gain chart that can assist you with the same.





Description BMI Score Healthy Weight Gain Range
Obese Higher than 29 – 30 Not higher than 7 kg
Overweight Between 25 – 30 Between 7 – 11 kg
Normal Between 18.5 – 26 Between 11 – 16 kg
Underweight Less than 18.5 Between 13 – 18 kg

The suggestions of your doctor might vary based on the scale used for calculating your BMI score.

How to Calculate BMI While Pregnant

Calculating your BMI when you are pregnant isn’t difficult. You need to get an approximation of the weight of your pregnancy from your doctor. Once you have that, you can deduct it from your total weight to get your true weight. This should be used to calculate your BMI. Based on this, there is a weight gain that is presumed to be healthy over the trimesters. The initial phase should show a weight gain of around half kilograms every month. As you enter the second trimester, it will be twice as before, which further increases to four times as that of the first when you are in the third trimester.




A pregnant woman on a weighing scale

Does BMI Change from Normal to Obese during Pregnancy?

BMI is a score that is calculated on the basis of your body weight as well as your height. During pregnancy, your weight increases, while your height stays the same. This results in your BMI score shifting to the higher side gradually, which could put you into the zone of overweight or obese as you proceed ahead in pregnancy. That isn’t a cause of worry as such, as long as your weight gain has been within the healthy limits as specified at the beginning of the pregnancy.

Obese BMI and Pregnancy Complications

With a high BMI during the third trimester of your pregnancy or at any stage for that matter, the chances of complications increase quite a lot, especially if the score is higher than 30. These can vary across a lot of possibilities such as:





  • Increased chances of delivering a stillborn.
  • A propensity to go for caesarean delivery instead of a normal vaginal one.
  • Infections.
  • Urinary tract infections or kidney issues.
  • Formation of blood clot anomalies.
  • A possibility of extreme bleeding following the delivery.
  • Increased risk of complications due to anaesthetics.
  • Foetus having various birth-related defects.
  • Obesity making it difficult to view the baby via ultrasound.
  • A higher chance of contracting pregnancy-induced diabetes.

Tips to Manage Your Weight during Pregnancy If Your BMI Is High

Pregnancy and excess weight is not a healthy combination. However, the presence of a high BMI score should not make you deter from proceeding ahead with your pregnancy. There are a bunch of tips you can adhere to, which will help you manage your weight better.

  • Opt for cereals or grains since those are extremely healthy and barely affect your weight gain at all.
  • Combining various vegetables and fruits, along with different legumes can provide you with the necessary energy throughout pregnancy.
  • Keep a track of your meat consumption, do not overdo it.
  • Exercise daily, starting with around 20 minutes daily, and ramping it up slowly.
  • Go for simple exercises such as walking or swimming, and try your hand at yoga to calm yourself and stay stress-free.

Precautions/Guidelines for Women with High BMI during Pregnancy

In case you have a high BMI during pregnancy, guidelines and precautions for you are extremely essential to make sure your pregnancy does not hit any roadblocks and proceeds ahead with minimal complications.




  • As a preventive measure, take suggestions from your weight loss expert before you try to conceive.
  • Calculate BMI as early as possible once you find out that you are pregnant.
  • Stay within the healthy parameters of weight gain for your BMI score.
  • Talk to your doctor or nutritionist to chalk out a proper diet that can help you balance the necessary nutrients as well as keep your weight under control.
  • Consult an instructor to create an exercise programme that is suitable for pregnancy.
  • Follow up with your cardiologist to check for any possible heart-related issues as well as your general doctor to check for the chances of having pregnancy-induced diabetes.

Motherhood is an experience you should not miss. If your weight does not fall within the realm of normalcy, you shouldn’t make it a reason for not getting pregnant. Yes, there are chances of higher risks and complications during delivery, but those can be handled by taking the right decisions well in advance.

Also Read: Weight Gain in Pregnancy: How much is Good?