Pregnancy Weight Gain Calculator
Estimate healthy pregnancy weight gain based on your pre-pregnancy BMI and current week. Uses 2009 Institute of Medicine guidelines (singleton + twin pregnancies).
5'4" = 64 inches.
Different IOM guidelines apply for twin pregnancies.
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Frequently asked questions
Is it normal to lose weight in the first trimester?
Yes, mild weight loss in the first trimester is common, especially with morning sickness. Up to 5% of pre-pregnancy weight loss is generally not concerning if you're eating and drinking enough to stay hydrated. Severe vomiting (hyperemesis gravidarum) affecting 1–3% of pregnancies needs medical management. By week 13–14, most women have either maintained or gained 1–4.5 lbs.
How much weight should I gain with twins?
Significantly more than with a singleton. IOM recommends: normal-BMI women carrying twins should gain 37–54 lbs total (vs. 25–35 for one baby); overweight 31–50 lbs (vs. 15–25); obese 25–42 lbs (vs. 11–20). Twin pregnancies don't have specific guidelines for underweight BMI because data is limited. Weekly gain rates in trimesters 2 and 3 are about 1.1–1.4 lbs/week for normal-BMI twin pregnancies.
When should I talk to my doctor about weight gain?
Always when: gaining more than 3 lbs in a single week after week 20 (possible preeclampsia warning), losing weight in the 2nd or 3rd trimester, gaining less than 0.5 lb/week consistently after week 20, or significantly outside the recommended range. Don't try to lose weight while pregnant unless directed — even women with high pre-pregnancy BMI should still gain some weight for fetal development.