How much weight should I gain during pregnancy?

The amount of weight you should gain depends on your pre-pregnancy Body Mass Index (BMI). For singleton pregnancies, women with normal BMI (18.5-24.9) should gain 25 to 35 lbs, underweight women should gain 28 to 40 lbs, overweight women 15 to 25 lbs, and obese women 11 to 20 lbs.

How is the weekly weight gain rate calculated?

During the first trimester (weeks 1 to 12), weight gain is minimal, usually between 1.1 and 4.4 lbs total. During the second and third trimesters, normal weight women are recommended to gain about 1.0 lb per week, overweight women 0.6 lb per week, and obese women 0.5 lb per week.

What are the recommended targets for twin pregnancies?

For twin pregnancies, the total weight gain recommendations are: 37 to 54 lbs for women with a normal pre-pregnancy BMI, 31 to 50 lbs for overweight women, and 25 to 42 lbs for obese women. Weekly rates in the 2nd and 3rd trimesters are higher, averaging 1.0 to 1.5 lbs per week.

Where does all the pregnancy weight go?

Maternal weight gain is distributed across several areas: baby (7.5 lbs), placenta (1.5 lbs), amniotic fluid (2 lbs), uterine muscle expansion (2 lbs), maternal breast tissue (2 lbs), maternal blood volume (4 lbs), fluids in maternal tissue (4 lbs), and maternal fat/protein stores (7 lbs) for breastfeeding.

Is it safe to lose weight during pregnancy?

In general, weight loss diets are not recommended during pregnancy, even for women who are overweight or obese, as the developing baby needs constant nutrients. Focus on eating nutrient-rich foods and maintaining light physical activities. Always consult your healthcare provider before modifying your weight target.

Pregnancy Weight Gain Calculator - Track Healthy Weight

Pregnancy Weight Gain Calculator

Track healthy pregnancy weight gain by week based on your pre-pregnancy BMI, with separate targets for single or twin pregnancies.

Pre-Pregnancy BMI Class	BMI Range	Singleton Pregnancy Target	Weekly Rate (2nd & 3rd Tri)	Twin Pregnancy Target	Twin Weekly Rate (2nd & 3rd Tri)
Underweight	< 18.5	28 – 40 lbs (12.7 – 18.1 kg)	1.0 lb/week (0.45 kg/week)	50 – 62 lbs (22.7 – 28.1 kg)*	1.5 lbs/week (0.68 kg/week)
Normal Weight	18.5 – 24.9	25 – 35 lbs (11.3 – 15.9 kg)	1.0 lb/week (0.45 kg/week)	37 – 54 lbs (16.8 – 24.5 kg)	1.5 lbs/week (0.68 kg/week)
Overweight	25.0 – 29.9	15 – 25 lbs (6.8 – 11.3 kg)	0.6 lb/week (0.27 kg/week)	31 – 50 lbs (14.1 – 22.7 kg)	1.25 lbs/week (0.57 kg/week)
Obese (Class I, II, III)	≥ 30.0	11 – 20 lbs (5.0 – 9.1 kg)	0.5 lb/week (0.23 kg/week)	25 – 42 lbs (11.3 – 19.1 kg)	1.0 lb/week (0.45 kg/week)

Pre-Pregnancy BMI Class

BMI Range

Singleton Pregnancy Target

Weekly Rate (2nd & 3rd Tri)

Twin Pregnancy Target

Twin Weekly Rate (2nd & 3rd Tri)

Underweight

< 18.5

28 – 40 lbs (12.7 – 18.1 kg)

1.0 lb/week (0.45 kg/week)

50 – 62 lbs (22.7 – 28.1 kg)*

1.5 lbs/week (0.68 kg/week)

Normal Weight

18.5 – 24.9

25 – 35 lbs (11.3 – 15.9 kg)

1.0 lb/week (0.45 kg/week)

37 – 54 lbs (16.8 – 24.5 kg)

1.5 lbs/week (0.68 kg/week)

Overweight

25.0 – 29.9

15 – 25 lbs (6.8 – 11.3 kg)

0.6 lb/week (0.27 kg/week)

31 – 50 lbs (14.1 – 22.7 kg)

1.25 lbs/week (0.57 kg/week)

Obese (Class I, II, III)

≥ 30.0

11 – 20 lbs (5.0 – 9.1 kg)

0.5 lb/week (0.23 kg/week)

25 – 42 lbs (11.3 – 19.1 kg)

1.0 lb/week (0.45 kg/week)

IOM Guidelines by Pre-Pregnancy BMI

Your pre-pregnancy weight and height determine a BMI category (Underweight, Normal, Overweight, or Obese), and each category from the Institute of Medicine guidelines carries its own total-gain range and recommended weekly gain rate for the second and third trimesters. Twin pregnancies use separate, higher targets in every category to support the additional fetus.

First-Trimester vs. Later Weeks

Weight gain in the first 12 weeks is modeled as a small, steady increase toward a 1.1 to 4.4 lb total, since early fetal growth requires comparatively little added maternal weight. From week 12 onward, gain accelerates at your category weekly rate, and the running total is capped at your BMI category maximum so the projection never exceeds the recommended range.

Worked Example

A woman with a Normal pre-pregnancy BMI (18.5-24.9) carrying a single baby gains roughly 0.8 to 1.0 lb per week after week 12. By week 20, that works out to an expected cumulative gain of about 7.5 to 12.4 lb, compared with a full-term target of 25 to 35 lb.

Using the Targets Responsibly

These ranges are general guidelines, not strict rules, and actual healthy gain varies by individual health, multiple pregnancy status, and medical history, so weight loss during pregnancy should only occur under a doctor's supervision. Pair this tracker with the Pregnancy Due Date Calculator to see your current week, or the Water Intake Calculator to help manage the added fluid needs of pregnancy.

Pregnancy Profile

Pregnancy Profiles Presets

Pregnancy Gain Report

Awaiting Pregnancy Profile Vitals

Weight Tracking Log

IOM Pregnancy Weight Gain Matrix

Pregnancy Sizing & Nutrition Science

Anatomy of Pregnancy Weight

Caloric Intake Guidelines

Maternal Physical Activity

AI Advisor Health Advisor

How Healthy Pregnancy Weight Gain Targets Are Set

IOM Guidelines by Pre-Pregnancy BMI

First-Trimester vs. Later Weeks

Worked Example

Using the Targets Responsibly

Questions, answered

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