What pregnancy week 33 means
Bones harden. “33 weeks pregnant” means 33 weeks have passed since the first day of the last menstrual period — the standard way pregnancy is dated. Conception usually happened about two weeks after that date, so the baby’s own age (fetal age) is roughly 31 weeks. Week 33 runs from 33 weeks 0 days to 33 weeks 6 days; on the following day the pregnancy is 34 weeks.
Your baby at 33 weeks
The bones are hardening, except for the skull, which stays soft and flexible to help with birth. The baby’s immune system is developing with antibodies passed through the placenta.
A common way to picture it: the baby is now about the size of a pineapple — roughly about 43.7 cm and about 1.9 kg. These are averages; babies grow at different rates, and ultrasound measurements vary.
Your body at 33 weeks
Swelling in the feet and ankles, lower back pain and pelvic discomfort are common. Some people feel pressure low in the pelvis.
Care and appointments around week 33
Pain in the pelvic joints that makes walking difficult can be helped with physiotherapy in many care systems — it is worth mentioning at your appointment.
The timing of tests and appointments differs between countries and care providers. If anything worries you — such as bleeding, severe pain, fluid leaking, fever, or a change in your baby’s movements — contact your midwife, doctor or maternity unit straight away rather than waiting for your next appointment.
Week 33 in your pregnancy timeline
Week 33 is in the third trimester (weeks 28–40+) and in pregnancy month 8, which covers roughly weeks 32–35. Early term begins at 37 weeks, 4 weeks from now.
| Pregnancy start (first day of last period) | |
|---|---|
| Estimated conception | |
| Full term (39 weeks) | |
| Estimated due date (40 weeks) |
Dates assume you are exactly 33 weeks 0 days today. For dates based on your own last period, use the calculator above or the main Pregnancy Calculator.
33 weeks pregnant in days and months
33 weeks is 231 days of pregnancy — 83% of a 40-week pregnancy. Counted in calendar months, 33 weeks is about 7.6 months, which is usually described as month 8 of pregnancy. Months are only a rough grouping; healthcare professionals almost always talk in weeks and days because they are more precise. See Pregnancy Month Calculator for how weeks map to months.