Determine and track your target pregnancy weight gain curve based on pre-pregnancy BMI and week of gestation.
A maternal-fetal medicine specialist evaluating gestational milestones monitors weight trends at every prenatal checkup. While managing nutrition and activity levels supports maternal health, tracking gestational weight gain serves as a primary marker for fetal development and placental health.
Pregnancy weight gain represents both the growth of the fetus and the maternal adaptations required to support life. Tracking weight helps ensure healthy progress for both mother and baby.
In 2009, the Institute of Medicine (IOM) and National Research Council updated weight guidelines based on pre-pregnancy BMI. These ranges aim to balance baby birthweight with maternal health.
| Pre-Pregnancy BMI Category | Recommended Gain (Singleton) | Recommended Gain (Twins) |
|---|---|---|
| Underweight (< 18.5) | 28 - 40 lbs (12.7 - 18.1 kg) | 50 - 62 lbs (22.7 - 28.1 kg) |
| Normal Weight (18.5 - 24.9) | 25 - 35 lbs (11.3 - 15.9 kg) | 37 - 54 lbs (16.8 - 24.5 kg) |
| Overweight (25.0 - 29.9) | 15 - 25 lbs (6.8 - 11.3 kg) | 31 - 50 lbs (14.1 - 22.7 kg) |
| Obese (>= 30.0) | 11 - 20 lbs (5.0 - 9.1 kg) | 25 - 42 lbs (11.3 - 19.1 kg) |
Weight gained during pregnancy is distributed across several maternal and fetal tissues. For a healthy 30-pound gain at term:
Staying within recommended ranges helps reduce pregnancy complications:
BMI is computed as `weight_kg / height_m^2`. Units are converted internally for weight tracking: `1 kg = 2.20462 lbs`. Weight gain is classified as On Track if it falls within the calculated target range for the current week.
In the first trimester, weight gain is minimal, typically between 1 and 4 pounds. Most weight gain happens during the second and third trimesters, averaging about 0.5 to 1 pound per week, depending on pre-pregnancy BMI.
No. Weight loss is generally not recommended during pregnancy, even for obese mothers, as it can limit the baby's nutrient supply. The focus should be on managing the rate of weight gain.
No extra calories are typically needed in the first trimester. In the second trimester, mothers need about 340 extra calories per day, and in the third trimester, about 450 extra calories per day to support healthy weight gain.
Due Date Calculator — Tracks pregnancy progress.
Ovulation Calculator — Determines ovulation dates.
BMI Calculator — Measures baseline weight classifications.