BMI Calculator and Healthy Weight Gain during Pregnancy

According to a 2015 Obstetrics & Gynecology study of more than 44,000 women, half of them have gained excess weight during pregnancy. Pregnant women with a high BMI are more at risk of maternal complications, and will require extra hospital care and incur higher medical expenses.

BMI calculator

Your Weight (kg) : Your Height (cm) : Your BMI: This Means:

In addition, being very overweight, or obese, which is normally considered having a body mass index of over 30, will lead to more than 20% of pregnant women suffering from gestational diabetes, a condition in which there is an increase in the blood sugar levels during pregnancy. According to Gema Sanabria-Martinez, who is a fetal and medicine researcher, women who develop gestational diabetes are at higher risk of developing Type 2 Diabetes after pregnancy.

Being obese during pregnancy can have a major impact on your health and your baby’s health. The majority of women who have gestational diabetes have healthy babies all the time. Even so, if gestational diabetes is not carefully managed it can result in uncontrolled glucose levels and may lead to several problems for both you and the baby, which include a C-section delivery, jaundice, low blood sugar (hypoglycemia), excessive birth weight, pre term birth, and high blood pressure as well as respiratory problems.

According to research conducted by Harvard Medical School, children of mothers who have gained excessive weight during pregnancy will be at a higher risk of being overweight at the age of 3, compared to those whose mothers gained a healthy amount of weight.

For most women, pregnancy weight gain is a natural process. However, for others, the problem (while less common) isn’t gaining too much weight; it’s gaining too little or, at times even losing weight during pregnancy. This can lead to serious health complications. In fact,infants born to mothers with a low BMI of 20 are more likely to be born prematurely and small for their birth weight. A recent Obstetrics & Gynecology study confirmed that 1 in 5 women have found it difficult to gain the right amount of pregnancy weight.

How Much Weight Gain during Pregnancy Is Normal?

The amount of weight you should gain during pregnancy depends on how much you weighed before you conceived and if that weight is appropriate for your height.

As outlined by the Institute of Medicine (IOM) this is how women should gain weight during pregnancy:

Table 1 : New Recommendations for Total and Rate of Weight Gain During Pregnancy, by Prepregnancy BMI

Prepregnancy BMI
BMI* (kg/m2)
Total Weight Gain (lbs)
Rates of Weight Gain* 2nd and 3rd Trimester
(lbs/week)
Underweight
< 18.5
28 ~ 40
1
(1 ~ 1.3)
Normal weight
18.5 ~ 24.9
25 ~ 35
1
(0.8 ~ 1)
Overweight
25.0 ~ 29.9
15 ~ 25
0.6
(0.5 ~ 0.7)
Obese (includes all classes)
≥ 30.0
11 ~ 20
0.5
(0.4 ~ 0.6)
Prepregnancy BMI
BMI* (kg/m2)
Total Weight Gain (lbs)
Rates of Weight Gain* 2nd and 3rd Trimester
(lbs/week)
Underweight
< 18.5
28 ~ 40
1
(1 ~ 1.3)
Normal weight
18.5 ~ 24.9
25 ~ 35
1
(0.8 ~ 1)
Overweight
25.0 ~ 29.9
15 ~ 25
0.6
(0.5 ~ 0.7)
Obese (includes all classes)
≥ 30.0
11 ~ 20
0.5
(0.4 ~ 0.6)

* Calculations assume a 0.5–2 kg (1.1–4.4 lbs) weight gain in the first trimester (based on Siega-Riz et al., 1994; Abrams et al., 1995; Carmichael et al., 1997)

As a result, determining your pre-pregnancy BMI is the easiest method to determine how the scale should change during pregnancy. (Calculate your BMI here.) Keep in mind that every woman’s pregnancy weight gain will be different and will be dependent on your pre-pregnancy BMI.

Gaining the Right Way

While you could be tempted to eat twice as much as you would normally eat during your pregnancy, there is simply no medical evidence that confirms that you have to.

It is your responsibility for developing a healthy baby,and through the correct food choices, exercise and eating healthy (not for two)you will increase the chances of having a healthy pregnancy and of course a healthy baby.

It is recommended that you avoid alcohol and caffeine entirely during pregnancy.Also,minimize your intake of sugar which includes sugary beverages. Keep in mind that the average women only require 200 to 300 calories daily in order to gain the right amount of pregnancy weight.


Staying active during your pregnancy has great benefits – it can help you get ready for labor and childbirth as well as lift your spirits – however you need to ensure that you practice safe workout routines, especially if you find it difficult to follow the nutritional guidelines above. If you worked out regularly before conception and your pregnancy is uncomplicated, the chances of you working out as before,with a few changes should be good. There are certain cases in which you will not be able to exercise during pregnancy, and this is ok, so please make sure that you seek advice from your doctor about what fitness routine is good for you and your baby.

And even though yoga and walking are regarded as excellent choices for prenatal workouts and should be included in your exercise program, if your routines were a lot more intense before conceiving, you don’t actually have to limit yourself to stereotypical “maternal” workouts.

According to Sanabria-Martinez, most women reduces exercising during pregnancy for the reason that they believe that exercising could lead to problems such as preterm deliveries or small babies and miscarriages. However, except if your doctor suggests otherwise (be sure to talk about physical exercise with your OB/GYN before you start with any workout routine during pregnancy), you should manage to continue your pre-pregnancy exercises throughout pregnancy. Also,exercising during pregnancy can lead to improved energy levels; better sleep cycles and reduces back pain.