Healthy weight gain is a normal and important part of pregnancy. Your body undergoes significant physiological changes to support your baby’s growth and development, including increases in blood volume, breast tissue, the size of the uterus, and the development of the placenta and amniotic fluid.
There is no single amount of weight that is considered appropriate for everyone. Healthy weight gain depends on several factors, including your pre-pregnancy body mass index (BMI), overall health, and individual pregnancy circumstances.
The focus should not be on achieving a perfect number on the scale. Instead, the aim is to support your health and your baby’s development through balanced nutrition, appropriate physical activity, and regular antenatal care.
Why Does Healthy Weight Gain Matter?
Weight gain during pregnancy supports several important changes in your body, including:
- Your baby’s growth and development
- The placenta and amniotic fluid
- Increased maternal blood volume
- Growth of the uterus and breast tissue
- Energy stores that support pregnancy and breastfeeding
For this reason, pregnancy weight gain should not simply be viewed as “putting on weight.” Much of the change reflects the normal physiological adaptations needed to support a healthy pregnancy.
Both excessive and insufficient weight gain may be associated with an increased risk of certain complications. However, these risks vary between individuals, which is why discussions about weight should always be individualised and considered alongside your overall health and your baby’s growth.
What Is Considered Healthy Weight Gain During Pregnancy?
Recommended weight gain during pregnancy is generally based on your BMI before pregnancy.
As a general guide for women carrying a single baby:
Pre-pregnancy BMI | Recommended total weight gain |
Underweight (below 18.5) | 12.5–18 kg |
Healthy weight (18.5–24.9) | 11.5–16 kg |
Overweight (25–29.9) | 7–11.5 kg |
Obesity (30 or above) | 5–9 kg |
These ranges are intended as a guide rather than a strict target. Your individual circumstances, medical history, nutritional status and your baby’s growth should all be considered when discussing appropriate weight gain.
Women carrying twins or higher-order pregnancies may have different recommendations.
How Does Weight Gain Change Throughout Pregnancy?
Weight gain does not necessarily occur at the same rate throughout pregnancy.
First Trimester
During the first trimester, weight gain is often minimal. Some women may gain very little weight or even lose a small amount, particularly if they are experiencing nausea or vomiting.
During this stage, maintaining adequate hydration and nutrition is generally more important than focusing on a specific number on the scale.
Second Trimester
Weight gain often becomes more consistent during the second trimester as nausea improves and your baby’s growth increases.
A balanced diet that provides adequate protein, vitamins, minerals and other essential nutrients becomes increasingly important during this stage.
Third Trimester
During the final months of pregnancy, your baby continues to grow and your body continues to adapt in preparation for birth and breastfeeding.
Regular antenatal care allows your healthcare team to assess your overall wellbeing and your baby’s growth throughout pregnancy.