Weight Gain During Pregnancy

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Pregnant woman

Weight and fundal (abdominal) measurements are usually recorded at prenatal appointments. However avoiding weight gain is a concern for many women, even during pregnancy. If the number on the scale is an issue or trigger, people can ask their doctor or midwife to record the number in their chart without telling them. Another option is to decline being weighed; many other things are measured throughout a pregnancy that can provide information about pregnancy health and fetal growth.

There used to be strict guidelines for weight-gain ranges, but an increasing body of research indicates it’s most important to focus on good nutrition and a healthy maternal patient, rather than an exact number of kilos gained through pregnancy. 

There are too many variables to pick an ideal number. Factors include height, pre-pregnancy body composition, bone structure, carrying a single fetus or multiples, genetics, metabolism, health of the pregnancy, diet, activity level, pre-existing health conditions, cultural considerations, age, and pregnancy-related health issues.

Someone who eats well will almost always gain exactly what they need for a healthy pregnancy. 

Where does the weight come from and where does it go?

Many postpartum women are surprised to find they don’t return to their pre-pregnancy weight immediately after birth. Less than half of the weight gained makes up the baby, placenta, and amniotic fluid!

Here’s a list of approximate weight distribution for a healthy pregnant woman of an “average-size” with a single fetus:

  • Baby at birth – average of 6-8.5lbs / 2700-3900g
  • Uterus* expands during pregnancy – 2lbs / 900g
  • Placenta – 1.5lbs / 680g
  • Breasts* – may increase by up to 1-2lbs / 450-900g (total, not each)
  • Blood volume* increases by 150% during pregnancy – 4lbs / 1800g
  • Fluid* will be retained by pregnant woman – up to 4lbs / 1800g
  • Amniotic fluid surrounds the baby – 2lbs / 900g
  • Maternal fat & nutrients stores, muscle development* – 7lbs / 3175g (3.175kg)

* These things do not magically disappear through the birth but rather will take some time to resolve. Good thing! It takes months to grow all the extra blood volume and other elements and it would feel quite terrible to undo all of it in a few hours. These things are a normal part of pregnancy. Some people return to their pre-pregnancy shape and weight while others do not.