33 weeks pregnant: bag packed, numbers saved

Babies keep their own calendar, so this is the week to get practical and ready, calmly.

Updated October 13, 2026 · sources checked October 13, 2026

In short

At 33 weeks the NHS says your baby is about 43.7cm from head to heel, with a fully developed brain and nervous system and a skull that stays soft for birth. Only about 1 in 20 babies arrive on their due date. The one thing to do this week: pack your hospital bag and save the numbers you will need in labour.

Where you are at 33 weeks

Month nine begins (Cleveland Clinic: weeks 33 to 36). Babies do things in their own time: ACOG and the NHS both say only about 1 in 20 arrive on their due date. Check where you are with our pregnancy week calculator and the due date calculator.

Your baby this week

The NHS measures your baby at about 43.7cm from head to heel and compares this to a pineapple. The brain and nervous system are now fully developed. The bones are hardening, except the skull bones, which stay soft and separate until around 12 to 18 months; that flexibility helps the head through the birth canal. ACOG describes weeks 33 to 36 the same way, and adds that fingernails reach the fingertips, limbs look chubbier and your baby may turn head-down for birth.

Your body and common symptoms

Tiredness, not surprising when you are carrying a couple of extra kilos.
Braxton Hicks. Tightening of the bump for 20 to 30 seconds, then relaxing. They should not hurt. If they become painful or regular, contact your midwife or hospital.
Heaviness in your pelvis. The NHS says this weighed-down feeling can be a sign your baby is head down.

Is this normal? When to call

Painless tightenings and pelvic heaviness are normal. Before 37 weeks, call your maternity unit or OB-GYN right away for painful or regular contractions, fluid leaking (a gush or a trickle), a change in discharge, pelvic pressure or a constant dull backache: ACOG says do not wait with signs of preterm labor. Call too for bleeding, reduced or changed movements, a severe headache, vision changes, pain below the ribs or sudden swelling. UK: NHS 111 if you cannot reach your unit, 999 in an emergency. US: 911 in an emergency.

Group B strep, simply

Group B strep is a common bacterium: the NHS says up to 2 in 5 people carry it, ACOG says about 1 in 4 pregnant women. It rarely causes problems, but there is a small risk it could make a newborn seriously ill, and most of those infections are preventable.

	United States	United Kingdom
Testing	ACOG: routine swab of the vagina and rectum between 36 and 38 weeks	NHS: routine testing is not currently recommended and rarely done; may be found during other tests
If positive	Antibiotics during labour, as your OB-GYN advises	Extra care and treatment in labour, as your midwife or doctor advises

If you go into labour before 37 weeks and your GBS status is unknown, ACOG says that is one of the situations where antibiotics may be given.

Your checklist for week 33

Pack your bag. The NHS list: birth plan and maternity notes, baby clothes and nappies, something loose and comfy for labour, spare clothes and underwear, nightclothes, nursing bras and breast pads, super-absorbent maternity pads, wash bag and towels, healthy snacks, any medicines. Our hospital bag checklist is printable.
Save in your phone, and write on paper in your bag: your maternity unit or labor and delivery number, your hospital reference number, your birth partner's number, the full address, and who will drive you (the NHS says it is not safe to drive yourself in labour).
Get the car seat: a new one is the safer choice, and practise fitting it before the day. In the UK, carrying a baby in your arms in a car is illegal, the NHS notes.
US: ask when your GBS swab is planned (36 to 38 weeks). UK: if you have a reason to be concerned, ask your midwife about GBS.
Review your birth plan with your partner or birth partner.

For your partner

Do a practice run to the hospital or birth centre, note where to park and which entrance is open at night.

Previous and next week

Week 32: position and vitamin K · Week 34 · The third trimester · All weeks

Questions parents ask

When should I pack my hospital bag?

The NHS week 33 guide suggests packing it now, so you are ready if your baby comes early. Only about 1 in 20 babies arrive on their due date.

Will I be tested for group B strep?

In the US, yes: ACOG recommends a swab of the vagina and rectum between 36 and 38 weeks. In the UK, routine testing is not currently recommended and tests are rarely done on the NHS, though a test may be offered if there is a reason; ask your midwife.

How many months pregnant is 33 weeks?

Cleveland Clinic groups weeks 33 to 36 as month nine, so at 33 weeks you are starting your ninth month.

Sources

NHS — Week-by-week guide: week 33 checked October 13, 2026
NHS — Group B strep checked October 13, 2026
ACOG — Group B Strep and Pregnancy checked October 13, 2026
ACOG — How Your Fetus Grows During Pregnancy checked October 13, 2026
Cleveland Clinic — Fetal Development: Week-by-Week Stages of Pregnancy checked October 13, 2026
ACOG — Preterm Labor and Birth checked October 13, 2026

Mamavela explains; it does not replace your midwife, doctor or pediatrician, who know your situation. If something worries you, call them. In an emergency, call 911 (US), 999 (UK) or 112.