Week 27 is the last week of the second trimester, and two-thirds of the way through. It is also, for most airlines, the last week you can fly without a letter. If travel is in your plans, this is the week to check the rules rather than the week to be surprised by them.
Your body this week
Weight is going on and bloating and constipation are common, partly because the stomach is being squeezed and partly because of progesterone. Water, high-fibre foods and plenty of fruit and vegetables are the usual answers.
Snoring often starts or worsens, because nasal passages swell in pregnancy.
Sleeping position becomes a safety point from next week. NHS guidance is that from 28 weeks it is safest to go to sleep on your side — for night sleep, for getting back to sleep, and for daytime naps — and that waking up on your back is not a problem, you simply turn back onto your side. Building the habit this week is easier than starting it next week.
What you may notice
Tiredness and sleep problems, stretch marks, sore gums, round ligament pains, piles, headaches, backache, nosebleeds, indigestion and heartburn, bloating and constipation, leg cramps, feeling hot, dizziness, swollen hands and feet, urine infections, vaginal infections, and skin and hair changes.
Movements are strong and regular for most women. Any change from what has become usual for you is a call to the maternity unit, at any hour.
Your baby this week
Around week 27, the length given is about 36.6cm from head to heel — the NHS compares it to a head of cauliflower. Population averages, and not a description of any particular pregnancy.
The lungs are now capable of breathing, and fat is filling out folds of skin that looked wrinkled a few weeks ago. Organs continue to mature.
What care usually happens around now
Nothing is routinely scheduled, but next week is a big appointment in most systems, so this is the week to write down anything you want to ask.
On travel: the NHS notes this is usually the last week you can fly without a letter from a midwife or doctor confirming an uncomplicated pregnancy, and that cut-offs vary by airline. ACOG's travel guidance similarly puts the safest window in the second trimester and advises checking airline rules and travel insurance. Rules differ by country and by carrier — check the actual airline, not a general article.
This week's tip
If you are flying, get the letter now and check your airline's cut-off in writing. Airlines refuse boarding on their own rules, not on how you feel or how far along you say you are, and a letter obtained at 27 weeks is straightforward while one obtained at 34 weeks may be impossible.
When to see a doctor
Contact your maternity service the same day for any change in movement. Report bleeding, severe pain, a fever, or a headache with vision changes. 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
Can I still fly?
Usually yes this week, and usually with a letter after it. Cut-offs vary by airline and are theirs to enforce, so check with the carrier before booking.
Do I really have to sleep on my side?
Guidance is to go to sleep on your side from 28 weeks. Week 28 starts the third trimester, and week 26 covers the week before. Waking on your back and turning over is fine.