# Day 85: How much to gain

> Most of the weight comes after week 20. Today you find your own range from your pre-pregnancy BMI, write one number to track with your provider, and rule out dieting.

- Series: Your third month of pregnancy, day by day (https://chorevia.com/learn/pregnancy-month-3), day 85 of 280, 12 weeks + 1 day
- Your baby this week: about the size of a plum; 5.4 cm from head to bottom
- Canonical URL: https://chorevia.com/learn/pregnancy-month-3/day-85
- Last reviewed: 2026-10-22
- Publisher: Chorevia (https://chorevia.com)
- Cite as: Chorevia. "Day 85: How much to gain." Last reviewed October 22, 2026. https://chorevia.com/learn/pregnancy-month-3/day-85

This guide is general education that summarizes published research and guidance from groups like the American Academy of Pediatrics, the CDC, and the WHO. It isn’t medical advice, and every child develops on their own timeline. Your pediatrician knows your child; if something feels wrong, call them. In an emergency, call 911.

Twelve weeks and one day. The question everyone has an opinion on, answered with the two numbers the sources give: a range and a pace.

## Your baby

Now 5.4cm long from head to bottom, about the size of a plum ([NHS](https://www.nhs.uk/best-start-in-life/pregnancy/week-by-week-guide-to-pregnancy/1st-trimester/week-12/)). The Office on Women's Health measures in inches: at 12 weeks the baby is about 3 inches long, weighs almost 1 ounce, and can make a fist ([OWH](https://womenshealth.gov/pregnancy/youre-pregnant-now-what/stages-pregnancy)). Almost none of what you gain this year is the baby yet.

## Your body

The NHS puts it this way: "Most mums-to-be will put on between 10kg and 12.5kg (22lb to 26lb), and that's usually after week 20." And then: "But some may not put on any weight at all" ([NHS](https://www.nhs.uk/best-start-in-life/pregnancy/week-by-week-guide-to-pregnancy/1st-trimester/week-12/)). The US ranges depend on your pre-pregnancy BMI: 28 to 40 pounds if underweight (BMI below 18.5), 25 to 35 pounds at a normal weight (18.5 to 24.9), 15 to 25 pounds if overweight (25.0 to 29.9), and 11 to 20 pounds with obesity (30.0 to 39.9); for twins at a normal weight, 37 to 54 pounds ([CDC](https://www.cdc.gov/maternal-infant-health/pregnancy-weight/index.html)).

The pace is slow at first. Most women gain 2 to 4 pounds in the first trimester, then about 1 pound a week for the rest of the pregnancy ([MedlinePlus](https://medlineplus.gov/ency/patientinstructions/000603.htm)). The first trimester generally needs no extra calories; the second needs about 340 more a day and the third about 450 ([CDC](https://www.cdc.gov/maternal-infant-health/pregnancy-weight/index.html)). And one rule with no exceptions: do not diet or try to lose weight during pregnancy ([MedlinePlus](https://medlineplus.gov/ency/patientinstructions/000603.htm)).

## Try today

### The weight-gain range

- **Time:** 5 minutes

1. Find your pre-pregnancy BMI category; the recommended range depends on it ([CDC](https://www.cdc.gov/maternal-infant-health/pregnancy-weight/index.html)).
2. Write the matching range from the CDC's list on one line of the notebook ([CDC](https://www.cdc.gov/maternal-infant-health/pregnancy-weight/index.html)).
3. Under it, write one number: your weight at the start. The CDC's advice is to track your gain from the beginning and compare it to the range as you go ([CDC](https://www.cdc.gov/maternal-infant-health/pregnancy-weight/index.html)).
4. Cross out the word "diet" anywhere it appears in your head ([MedlinePlus](https://medlineplus.gov/ency/patientinstructions/000603.htm)).
5. Bring the page to your next visit; the CDC says to work with your provider on the goal ([CDC](https://www.cdc.gov/maternal-infant-health/pregnancy-weight/index.html)).

**Make it work:** If your situation isn't on the list, such as triplets or a BMI above 39.9, that's a conversation with your provider, not a guess ([CDC](https://www.cdc.gov/maternal-infant-health/pregnancy-weight/index.html)).

## Watch for

- **Normal:** no weight gained yet, or a pound or two; the first-trimester pace is 2 to 4 pounds, and some gain nothing at all ([MedlinePlus](https://medlineplus.gov/ency/patientinstructions/000603.htm); [NHS](https://www.nhs.uk/best-start-in-life/pregnancy/week-by-week-guide-to-pregnancy/1st-trimester/week-12/)). **Call your provider** if you lose more than 2 pounds (1 kilogram) in a week ([MedlinePlus](https://medlineplus.gov/ency/patientinstructions/000604.htm)).
- **Normal:** appetite coming back as the sickness eases ([NHS](https://www.nhs.uk/best-start-in-life/pregnancy/week-by-week-guide-to-pregnancy/1st-trimester/week-12/)). **Call your provider** for sudden swelling in your hands or feet, or rapid weight gain ([OWH](https://womenshealth.gov/pregnancy/youre-pregnant-now-what/body-changes-and-discomforts)).
- **Normal:** unsure whether to keep exercising. **Call your provider** about any restrictions; activity is healthy and safe for most pregnant women ([CDC](https://www.cdc.gov/maternal-infant-health/pregnancy-weight/index.html)).

## For you

Track it with your provider, not alone ([CDC](https://www.cdc.gov/maternal-infant-health/pregnancy-weight/index.html)). The number on the scale is one of several things checked at every visit ([OWH](https://womenshealth.gov/pregnancy/youre-pregnant-now-what/prenatal-care-and-tests)). A previous study found only about 1 in 3 women gained the recommended amount ([CDC](https://www.cdc.gov/maternal-infant-health/pregnancy-weight/index.html)); the range is a guide, not a grade.

If your starting weight is higher than you'd like, the CDC's line still stands: don't try to lose weight if you're already pregnant, because some gain is needed for a healthy baby ([CDC](https://www.cdc.gov/diabetes/about/gestational-diabetes.html)).

If you're the partner: never be the scale. Cook the balanced plate the CDC describes, whole grains, vegetables, fruit, low-fat dairy and lean protein ([CDC](https://www.cdc.gov/maternal-infant-health/pregnancy-weight/index.html)), and leave the number to her and the clinic.

## Sources

- NHS. "Week 12." Week-by-week guide to pregnancy, Best Start in Life. https://www.nhs.uk/best-start-in-life/pregnancy/week-by-week-guide-to-pregnancy/1st-trimester/week-12/
- Office on Women's Health. "Stages of pregnancy." U.S. Department of Health and Human Services. https://womenshealth.gov/pregnancy/youre-pregnant-now-what/stages-pregnancy
- Centers for Disease Control and Prevention. "Weight Gain During Pregnancy." https://www.cdc.gov/maternal-infant-health/pregnancy-weight/index.html
- MedlinePlus. "Managing your weight gain during pregnancy." National Library of Medicine. https://medlineplus.gov/ency/patientinstructions/000603.htm
- MedlinePlus. "Morning sickness." National Library of Medicine. https://medlineplus.gov/ency/patientinstructions/000604.htm
- Office on Women's Health. "Body changes and discomforts." U.S. Department of Health and Human Services. https://womenshealth.gov/pregnancy/youre-pregnant-now-what/body-changes-and-discomforts
- Office on Women's Health. "Prenatal care and tests." U.S. Department of Health and Human Services. https://womenshealth.gov/pregnancy/youre-pregnant-now-what/prenatal-care-and-tests
- Centers for Disease Control and Prevention. "Gestational Diabetes." https://www.cdc.gov/diabetes/about/gestational-diabetes.html