The short answer
31 weeks = 7 months
At 31 weeks pregnant, you are about 7 months pregnant — in month 7 of your pregnancy and in your third trimester.
Not sure of your week? Use the pregnancy week calculator to find it from your last period, due date or conception date.
Major development is largely complete — from here the main job is gaining weight and maturing the lungs and brain.
About the size of a coconut
size comparison
41.1 cm
crown to heel (16.2 in)
1.5 kg
average weight (3.3 lb)
The brain can now process information, track light and perceive signals from all five senses. The lungs are more mature but still developing surfactant, and the fetus is passing about half a liter of urine into the amniotic fluid daily. Nails have reached the fingertips.
Sizes and weights are averages — healthy babies vary widely, and your scan measurements are what count.
Braxton Hicks may become more noticeable and frequent, especially after activity. Breast tenderness can return, and colostrum leakage is common. Sleeping through the night is a rarity for many people now.
Common symptoms this week
63
days to go
9
weeks to go
217
days so far
At 31 weeks 0 days you are 217 days into a 280-day pregnancy, which leaves 63 days — 9 weeks — until 40 weeks. That number drops by one for every day you move through this week. Remember the due date is an estimate: only about 1 in 20 babies is born on it, and most arrive within two weeks on either side.
Next milestone: 42 days until early term (37 weeks 0 days).
A calendar month averages about 4.3 weeks — not 4 — so you can't just divide your week number by four. Instead, months of pregnancy are counted as uneven buckets of 4 to 5 weeks, arranged so the full 40 weeks fits into 9 calendar months. Week 31 falls in month 7, in the third trimester.
Your care team will always use weeks and days rather than months, because screening windows and term definitions are set by exact week — months are just the everyday shorthand. For the full conversion, see the weeks to months chart, or go the other way with the months-to-weeks guide.
Your notes will show a week and a day — 31+3 or 31w3d, for example. Pick the exact day you are on for its own day count, countdown and month answer.
| Week + day | Shorthand | Days pregnant | Days to go |
|---|---|---|---|
| 31 weeks 0 days (this page) | 31+0 | 217 | 63 |
| 31 weeks 1 day | 31+1 | 218 | 62 |
| 31 weeks 2 days | 31+2 | 219 | 61 |
| 31 weeks 3 days | 31+3 | 220 | 60 |
| 31 weeks 4 days | 31+4 | 221 | 59 |
| 31 weeks 5 days | 31+5 | 222 | 58 |
| 31 weeks 6 days | 31+6 | 223 | 57 |
At 31 weeks pregnant, you are about 7 months pregnant — in month 7 of your pregnancy and in your third trimester. Months of pregnancy are counted as uneven 4–5 week buckets so that the full 40 weeks fits into 9 calendar months.
31 weeks is in the third trimester, which runs from 28 weeks 0 days until birth. Full term begins at 39 weeks 0 days.
About 9 weeks until the 40-week mark — though only about 1 in 20 babies arrives exactly on the due date. Most are born within two weeks on either side of it.
At 31 weeks 0 days you are 217 days into a 280-day pregnancy, so there are 63 days left until the 40-week mark — that's 9 weeks. The count drops by one for each day you move through week 31.
31 weeks is 217 days, counted from the first day of your last menstrual period (31 × 7 = 217). Add the days into your current week for the exact figure — for example 31 weeks 3 days is 220 days.