Week 33 is the packing week. Babies arrive on their own schedule — the NHS puts the number arriving on their due date at about one in twenty — so having a bag ready is not pessimism, it is arithmetic. This is also the week to ask about group B strep.
Your body this week
Braxton Hicks tightenings become more noticeable: a tightening across the bump for 20 to 30 seconds, then relaxing. They should not hurt. If they become painful or settle into a regular rhythm, contact a midwife or hospital, because that is how early labour can present.
A heavy, weighed-down feeling in the pelvis is common and often means the head has moved down into position. It does not mean labour is starting.
Tiredness at this stage is largely mechanical — you are carrying a couple of extra kilograms everywhere you go.
What you may notice
Braxton Hicks contractions, sleep problems, stretch marks, sore gums, round ligament pains, piles, headaches, backache, indigestion and heartburn, bloating and constipation, leg cramps, feeling hot, dizziness, swelling, urine infections, vaginal infections, and skin and hair changes.
Movements should not be reducing. A change in your own pattern is a call to the maternity unit at any hour.
Your baby this week
Around week 33, the length given is about 43.7cm from head to heel — the NHS compares it to a pineapple. Averages describing a population, not a measurement of an individual pregnancy.
The brain and nervous system are fully developed. Bones are hardening, except for the skull bones, which stay soft and separated until somewhere around 12 to 18 months old — the flexibility that makes the journey through the birth canal possible.
What care usually happens around now
Group B strep is worth asking about this week. ACOG describes it as a common bacterium carried by many adults without symptoms, which can occasionally make a newborn seriously unwell, and describes routine screening late in pregnancy in the US. The NHS does not screen everyone routinely and manages it based on risk factors, so this is a genuine difference between countries and one to ask your own midwife about.
The whooping cough vaccination is best given before this week in the UK for protection to reach a baby, though it can still be given later. Antenatal appointment schedules differ; the next UK appointment for most women is around week 34.
This week's tip
Store the maternity unit's number, your hospital reference number, your birth partner's number and the full address of where you are going in your phone, and write them on paper in the bag too. The NHS suggests exactly this, and the reason is unglamorous: phones run out of battery, and nobody remembers an address while having contractions.
When to see a doctor
Contact your maternity service the same day for any change in movement, leaking fluid, regular or painful tightenings, or bleeding. Pregnancy warning signs has the full list.
Seek care now: Contact your local emergency services or go to your nearest emergency department if you have heavy bleeding, severe or one-sided tummy pain, a severe headache with vision changes, sudden swelling of the face or hands, a fever, fluid leaking from the vagina, chest pain, trouble breathing, fainting, or a seizure. Contact your maternity service the same day for any reduction in your baby's usual pattern of movement. Femio cannot assess a pregnancy.
Frequently asked questions
Will I be tested for group B strep?
It depends where you are. Some countries screen everyone late in pregnancy; others, including the UK, manage it on risk factors. Ask your midwife what applies to you.
What goes in the hospital bag?
Notes and birth plan, loose comfortable clothes, nightwear, spare underwear, nursing bras and breast pads, absorbent maternity pads, a wash bag and towels, snacks, any medicines, and clothes and nappies for the baby. Week 34 covers engagement, and week 32 covers position.