Pregnancy weight gain guide
Pregnancy weight gain guidelines by pre-pregnancy BMI
Pregnancy weight-gain recommendations depend mainly on your pre-pregnancy body mass index (BMI) and whether you are carrying one baby or twins. The published ranges are general population guidance, not a number every individual pregnancy must hit exactly.
Weight-gain ranges for one baby
Start with your pre-pregnancy BMI category. CDC and the National Academies publish these total-gain ranges for a singleton pregnancy; they are population guidance, not an exact personal target.
| Pre-pregnancy BMI | Category | Total gain (lb) | Total gain (kg) |
|---|---|---|---|
| <18.5 | Underweight | 28–40 lb | 12.5–18 kg |
| 18.5–24.9 | Normal | 25–35 lb | 11.5–16 kg |
| 25.0–29.9 | Overweight | 15–25 lb | 7–11.5 kg |
| ≥30 | Obesity | 11–20 lb | 5–9 kg |
The Pregnancy Weight Gain Calculator can calculate a pre-pregnancy BMI category and show the matching total range.
Weight-gain ranges for twins
CDC publishes separate total ranges for a twin pregnancy. A singleton range should not simply be doubled.
| Category | Total gain (lb) | Approximate kg |
|---|---|---|
| Underweight | 50–62 lb | ~22.7–28.1 kg |
| Normal | 37–54 lb | ~16.8–24.5 kg |
| Overweight | 31–50 lb | ~14.1–22.7 kg |
| Obesity | 25–42 lb | ~11.3–19.1 kg |
The underweight twin range is included in CDC’s public table. It is presented here as CDC guidance rather than relabeled as a separate National Academies recommendation.
How guidance changes across pregnancy
A commonly used first-trimester context is about 0.5–2.0 kg (1.1–4.4 lb) in total. For the second and third trimesters, published guidance also provides approximate weekly rate ranges based on pre-pregnancy BMI.
| Pre-pregnancy category | kg per week | lb per week |
|---|---|---|
| Underweight | 0.44–0.58 kg/wk | 1.0–1.3 lb/wk |
| Normal | 0.35–0.50 kg/wk | 0.8–1.0 lb/wk |
| Overweight | 0.23–0.33 kg/wk | 0.5–0.7 lb/wk |
| Obesity | 0.17–0.27 kg/wk | 0.4–0.6 lb/wk |
These later-pregnancy rates are rate context, not a guaranteed weekly trajectory, an official week-by-week cumulative band, a personal target, or a diagnosis.
No. Weight gain does not have to follow a perfectly straight line from one week to the next. Day-to-day and week-to-week body weight can vary, while published rate guidance describes a broader population pattern rather than requiring every measurement to rise by the same amount.
Rapid, large, unexpected, or clinically concerning changes need interpretation from the prenatal care team. A general table cannot diagnose a cause or prescribe what to do.
How to interpret these ranges
The guideline categories use the starting BMI before pregnancy because current pregnancy weight already includes pregnancy-related change. The category organizes population guidance; it is not a judgment about someone’s body.
Individual advice can differ because a clinician can consider information this page does not have, including health history, pregnancy complications, fetal growth, symptoms, nutrition, and other clinical findings. Your care team’s individualized guidance takes priority over a general online reference.
The sources used here do not provide one general numeric target equivalent to the singleton and twin tables for triplets or higher-order pregnancies. Use individualized guidance rather than extending or multiplying either table.
For supported singleton results, the calculator can show an optional derived reference based on the entered baseline. That is Pregnancy Metrics' model, not an official CDC week-by-week band or individualized medical target.
Official sources
Current public guidance still relies substantially on the National Academies framework used by CDC. These sources support the ranges and rate context; they do not review or endorse Pregnancy Metrics.
- CDC — Weight Gain During Pregnancy
Publishes total weight-gain ranges for singleton and twin pregnancies by pre-pregnancy BMI.
- ACOG — Weight Gain During Pregnancy
Explains BMI-based recommendations, later-pregnancy rate context, and individualized clinical care.
- National Academies — Weight Gain During Pregnancy: Reexamining the Guidelines
Provides the evidence framework behind the commonly used 2009 recommendations.
- NCBI Bookshelf — Summary / Table S-1
Summarizes singleton total ranges and second- and third-trimester rate guidance.