mybabybase

Third trimester

33 weeks pregnant

Baby is about the size of a pineapple.

Week 33 of 40 · in your third trimester · Updated

Your baby this week

Baby's bones are hardening except for the skull — that stays soft for delivery.

  • All baby's bones are hardening except the skull — which stays in plates that can overlap slightly for delivery.
  • Baby's pupils dilate and constrict in response to light.
  • Baby weighs about 4 lbs (1.8 kg).

Your body this week

Pelvic pressure increases as baby drops a bit lower.

  • Many women develop more confidence in their body's ability — and others get more anxious. Both normal.
  • You may feel tired and uncomfortable doing everyday things — this is OK.
  • Sleep on your left side if you can.

Common symptoms

  • Continued fatigue
  • Frequent urination
  • Pelvic pressure
  • Difficulty bending
  • Strong kicks

Things to do this week

  • Install car seat (have it inspected at fire station)
  • Take childbirth class if you haven't
  • Prepare freezer meals for after birth

For partners this week

Nesting jobs

  • Install the car seat and get it checked if you can.
  • Sign up for a prenatal class together.
  • Cook a few freezer meals for after the birth.

Typical visits around this week

Based on a typical schedule in Ontario. Your doctor or midwife sets the actual timing.

  • RSV vaccine (if baby is due in RSV season)

    Weeks 32–36 · if it applies to you

    If your baby is expected during RSV season (roughly fall to spring), a vaccine in pregnancy is one way to protect them; the other is an antibody given to the baby after birth. Ontario offers the pregnancy vaccine free at 32–36 weeks (national guidance says it can be given from 28 weeks). Your provider will help you choose.

    Questions to ask →
    • Is my baby due during RSV season?
    • Should I get the vaccine, or should the baby get the antibody after birth?
    • Where can I get the RSV vaccine?
    • If I get it, does the baby still need anything after birth?

  • Routine check-ups (about every 2 weeks)

    Weeks 28–36

    From about 28 weeks, check-ups usually come every 2 to 3 weeks. Your provider keeps an eye on your blood pressure, the baby's growth and heartbeat, and will talk about feeling the baby move.

    Questions to ask →
    • How should I keep track of the baby's movements?
    • Which symptoms mean I should call right away?
    • When should we register at the hospital or plan our birth place?
    • Are prenatal classes available near us?

Coming up

  • Group B strep swab

    Weeks 35–37

    A quick vaginal and rectal swab, usually between 35 and 37 weeks, to check for group B strep bacteria. If it's positive, you'll be offered IV antibiotics during labour or if your water breaks.

    Questions to ask →
    • Can I do the swab myself?
    • How will I find out the result?
    • If it's positive, what happens when I go into labour?

  • Weekly check-ups

    Weeks 36–40

    From about 36 weeks, visits are usually weekly until birth. Your provider checks the baby's position and your health, and goes over signs of labour and when to come in.

    Questions to ask →
    • Is the baby head-down?
    • When exactly should we call or head to the hospital?
    • What's the plan if my water breaks before contractions start?
    • What happens if I go past my due date?

A flu shot and a COVID-19 vaccine are recommended at any stage of pregnancy. The flu shot is given during flu season, so the timing depends on when you're pregnant.

When to call your doctor or midwife

Bleeding, fluid leaking, a bad headache or vision changes, or baby moving less than usual all need a call. See the warning signs and who to call →

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Further reading from health authorities