Third trimester: weeks 28 to 42
What changes, what gets checked, and what to watch for — week by week.
The third trimester runs from week 28 to week 42. Each week below has its own page with your baby's size, how you may feel, what is offered clinically, and the signs worth a call.
Pregnancies differ, and so do the dates a clinic works to. Treat the week numbers as the common pattern rather than a schedule you are behind on.
Every week of the third trimester
- 28 weeks pregnant — about the size of a eggplant
- 29 weeks pregnant — about the size of a eggplant
- 30 weeks pregnant — about the size of a cabbage
- 31 weeks pregnant — about the size of a cabbage
- 32 weeks pregnant — about the size of a squash
- 33 weeks pregnant — about the size of a squash
- 34 weeks pregnant — about the size of a cantaloupe
- 35 weeks pregnant — about the size of a cantaloupe
- 36 weeks pregnant — about the size of a romaine lettuce
- 37 weeks pregnant — about the size of a romaine lettuce
- 38 weeks pregnant — about the size of a leek
- 39 weeks pregnant — about the size of a leek
- 40 weeks pregnant — about the size of a small pumpkin
- 41 weeks pregnant — about the size of a small pumpkin
- 42 weeks pregnant — about the size of a watermelon
What nutrition matters most now
The nutrients these weeks call out, each with what it does and how much you need.
Common questions
Which weeks are the third trimester?
Weeks 28 to 42. Clinics count from the first day of your last period, so the dates on your notes may differ slightly from how far along you feel.
What tests happen in the third trimester?
Anti-D prophylaxis if Rh-negative; Repeat Hb; Group-B strep swab (weeks 35–37); Presentation / growth check. What is offered varies by country and by your own history.
How might I feel in the third trimester?
Entering the third trimester, frequent urination often returns as the baby grows. Backache and shortness of breath commonly continue. Braxton Hicks contractions and heartburn are commonly more noticeable. Prenatal visits are typically scheduled more frequently from here (often every two weeks until 36 weeks).
Show the evidence
Sources: ACOG, WHO, NHS, UNSW Embryology.
This page gathers and links what the individual week and nutrient pages already publish — it introduces no figure they do not carry, and each one names its own source.
Educational reference, not medical advice. Pregnancies and the care offered around them differ; follow the team looking after you.