Gaining weight in pregnancy is natural and necessary. Only part of the weight gained belongs to the baby. The rest comes from the placenta, amniotic fluid, increased blood volume, the growing uterus, breast tissue and the mother's energy stores. So the goal is not to avoid gaining weight but to gain within a healthy range at a balanced pace. Gaining too little or too much can affect both the pregnancy and the baby's development.
Recommended total weight gain depends on your body mass index (BMI) before pregnancy. Under widely accepted ranges, a mother with a normal BMI gains 11.5 to 16 kg (25 to 35 lb) in total. The range is higher for those who start underweight and lower for those who start overweight. Ranges are different for twin pregnancies and show the mother's total gain.
Weight gain is usually small in the first three months, and gaining nothing because of nausea is also common. Most of the gain happens in the second and third trimesters. Weighing yourself regularly under the same conditions, for example in the morning before eating, helps you see the real trend. Your doctor sets the right target for you. Looking at the overall trend across weeks means more than any single reading. If you notice a sudden gain or loss, talk to your doctor.
What you can do
- Add, edit and delete weight entries with a date and note.
- See your BMI category based on pre-pregnancy weight and height.
- Track the recommended total weight gain range for your BMI.
- Use separate ranges for twin and triplet pregnancies.
- Follow week by week changes on the weight chart.
- Get an AI review of your weight trend after at least 3 entries.
How to use it
- Enter your pre-pregnancy weight and your height.
- Add your weight along with the date you measured it.
- Follow your progress on the chart and the recommended range indicator.
- If you are clearly outside the range, discuss it with your doctor at your checkup.
Frequently asked questions
How much weight should I gain during pregnancy?
It depends on your BMI before pregnancy. The widely accepted ranges are: BMI under 18.5, 12.5 to 18 kg (28 to 40 lb); BMI 18.5 to 24.9, 11.5 to 16 kg (25 to 35 lb); BMI 25 to 29.9, 7 to 11.5 kg (15 to 25 lb); BMI 30 or above, 5 to 9 kg (11 to 20 lb). Ranges are higher for twins. Your doctor sets the right target for you.
How much weight should I gain per week while pregnant?
In the first trimester, total gain usually stays between 0.5 and 2 kg. In the second and third trimesters, a mother with a normal BMI can expect to gain about 0.4 to 0.5 kg (roughly 1 lb) per week. It is a little more for those who start underweight and less for those who start overweight. The overall trend matters more than individual weeks.
Is it normal not to gain weight in the first trimester?
Yes, it is often normal. In the first three months, not gaining or even losing a little weight because of nausea, vomiting and poor appetite is common. Your baby's needs are small at this stage. But if you are vomiting constantly, cannot keep fluids down or are losing noticeable weight, see your doctor to be checked for hyperemesis.
How do you calculate pregnancy weight gain?
Weight gain is your current weight minus your pre-pregnancy weight. To assess it, your BMI is first calculated from your pre-pregnancy weight and height, then compared with the recommended range for that BMI. That is why entering your starting weight correctly matters. Weighing at a similar time and in similar clothes each time makes results more consistent.