Weight Gain To Expect During Pregnancy

With the birth of their first, or even subsequent children, women often have questions about what is an acceptable weight gain during pregnancy. Often women have misconceptions about weight gain during pregnancy, how much is healthy and also feeling as if they may be contributing to obesity.

Previously doctors believed that a weight gain of 20 –25 pounds was appropriate but now they know that the amount of weight a woman gains during pregnancy should in fact be based on her pre-pregnancy weight. Your baby will take what nutrition it needs from the woman’s body. When women don’t take in enough nutrition they are at risk for delivering an underweight baby. Babies who are born at low birth weight are at higher risk for specific health disorders that affect the lungs, neurological and gastrointestinal systems. (1)

An acceptable weight gain during pregnancy often occurs in the third trimester because that is when the baby gains the majority of his weight and size. Your hunger increases in the first and second trimester because it takes a lot of energy for your body to grow this new little person. You should be eating a well balanced diet that doesn’t have excessive fat or sugar.

Doctors now know that how much you gain during pregnancy depends upon how much you weighed before you became pregnant. Those who weighed less than within normal limits for their height should gain more and those who weight more should gain less. That’s not very specific. So the US National Academy of Sciences produced a table of recommended weight increases during pregnancy based on your pre-pregnancy BMI. (2)

Your BMI or body mass index, is a way of measuring how close to a normal weight your are using a mathematical equation taking your height and weight into account. The actual equation is your height, squared, divided into your weight and multiplied by 705. If you use a metric system you divide your weight in kilo’s by your length in meters twice.

For instance if you are 5’4” and 120 pounds: 120/ (64X64) X 705 = 20.65 (BMI).
In metrics the weight 55.54 and height is 1.62 meters – divide the weight by height twice and the BMI = 21.1

The National Academy of Sciences acceptable weight gain during pregnancy table recommends a weight gain of 27-39 pounds if the BMI is less than 19.8; about 25-35 pounds if your BMI is 19.8-26; about 15-25 pounds if your BMI is 26-29 and at least 13 pounds if your BMI is over 29.

Weight gain during pregnancy should never be mistaken for obesity. The dictionary defines obesity as excessive accumulation of fat but weight gain during pregnancy is because of the additional weight of increased blood supply, water, placenta and baby.

Many women also mistake the weight gain during pregnancy and difficulty losing the weight after pregnancy as a reason not to gain weight during pregnancy. Unfortunately this increases the risk of babies who are low birth weight who have neurological, gastrointestinal and temperature regulation problems. Some of these difficulties are long term and last a lifetime.

(1) March of Dimes: Low Birthweight

(2) National Center for Biotechnology Information: Guidelines For Weight Gain During Pregnancy