At 27 weeks pregnant (27+0 to 27+6 weeks from the first day of your last period) you are about 6 months and 6 days along, in the 7th month of pregnancy. This is the last week of the second trimester and you are two-thirds of the way through; the third trimester starts next week. Your baby's skin is filling out with fat and they are getting plumper by the day.
Counted from your last period, 27 weeks pregnant is about 6 months and 6 days, so you are in the 7th month. This week covers days 189 to 195; you are still in the second trimester, with about 91 days to your due date.
According to the NHS, your baby is about 36.6 cm long from head to heel. The skin, which looked wrinkled a few weeks ago, is filling out with fat; all the organs are maturing and your baby is getting plumper every day.
Sources put the emphasis on the lungs differently: the NHS says your baby's lungs are now capable of breathing. ACOG says that during weeks 25 to 28 the lungs are fully formed but not yet ready to work outside the womb, and begin to make surfactant.
ACOG's list for weeks 25 to 28 adds that the eyelids can open and close, the nervous system is developing, and the skin looks smoother as fat is added.
ACOG defines the second trimester as 14+0 to 27+6 weeks and the third as 28+0 to 40+6 weeks, so throughout week 27 you are still in the second trimester.
You may be putting on some weight and feeling bloated and constipated, partly because your stomach is squeezed by the growing baby and partly because of the hormone progesterone. Drinking plenty of water, choosing high-fibre options such as wholemeal bread and wholewheat pasta, and eating lots of fresh fruit and vegetables can help (NHS). The Turkish Ministry of Health guideline suggests gaining no more than 2 kg a month if you started at a healthy weight or underweight, and no more than 1 kg if you were overweight or obese.
Nap when you can if you are tired. You may also snore more, because the inside of the nose swells and blocks more easily in pregnancy (NHS).
Sleeping on your side. NICE advises not going to sleep on your back after 28 weeks and explains there may be a link between back-sleeping and stillbirth in late pregnancy; the NHS also says sleeping on either side is better than on your back. Support your bump with a pillow, keep your knees bent and put a pillow between your legs. Do not worry if you wake up on your back; just roll onto your side again (NHS).
Flying. The NHS says this is probably the last week you can fly without a "fitness to fly" letter; after this you may need a note from your midwife or doctor confirming your pregnancy is uncomplicated. Check the rules with your airline.
How much does the baby weigh? In the reference table of the World Health Organization's fetal growth study across 10 countries (2017), the median (50th percentile) estimated weight at 27 weeks is about 1,039 g; the 10th percentile is 898 g and the 90th percentile 1,196 g. These are reference values, not your own baby's measurement. The study notes differences between countries, maternal characteristics and the baby's sex, so these charts may need adjusting for local use. The growth trend matters more than a single measurement.
| Symptom | Usually | Seek care if |
|---|---|---|
| Bloating and constipation | Common because of the baby's pressure and progesterone; water, fibre, fruit and vegetables help. | Get help straight away for severe tummy pain or bleeding (NHS). |
| Backache | One of the common second-trimester symptoms the NHS lists. | New low backache with regular tightenings, period-like cramps or pelvic pressure can be a sign of preterm labour (UpToDate). |
| Waking up on your back | Do not worry; just roll onto your side again when you notice. | Tell your midwife or doctor if poor sleep leaves you too tired to cope (NHS). |
Contact your midwife, doctor or maternity unit straight away if you have:
Most of these are danger signs or emergency referral criteria in the Turkish Ministry of Health Antenatal Care Management Guideline (2026); tightenings, cramps, backache and pelvic pressure are on UpToDate's list of preterm labour signs. Headache, vision problems, facial swelling, pain below the ribs and high blood pressure can be signs of pre-eclampsia (NHS, UpToDate). The NHS says to call if your baby's movements reduce, stop or change, without waiting until the next day, even at night. The RCOG says that between 24 and 28 weeks your baby's heartbeat, womb size, blood pressure and urine are then checked; do not rely on a home doppler.
No. ACOG says the second trimester runs to 27 weeks and 6 days and the third starts at 28 weeks and 0 days. The NHS also calls week 27 the last week of the second trimester.
NICE advises not going to sleep on your back after 28 weeks, explaining there may be a link between back-sleeping and stillbirth in late pregnancy. It is a good idea to get used to sleeping on your side now. If you wake up on your back, do not worry; roll onto your side again (NHS).
The NHS says this is probably the last week you can fly without a "fitness to fly" letter; after that you may need a note from your midwife or doctor confirming an uncomplicated pregnancy. Cut-off dates vary between airlines, so check with yours.
Organisations differ: the Turkish Ministry of Health recommends the first dose at 18 to 24 weeks, or up to the end of week 32 if missed; the NHS gives weeks 16 to 32 (usually around week 20); the US recommendation described by UpToDate is ideally 27 to 36 weeks in every pregnancy.
In the reference table of the World Health Organization fetal growth study (2017), the median estimated weight at 27 weeks is about 1,039 g, with the 10th percentile at 898 g and the 90th at 1,196 g. These are reference values; an ultrasound weight is itself an estimate with a margin of error, so the growth trend matters more than a single measurement.
Last updated: . All sources have been confirmed with their latest versions. This content is for educational purposes and is not a substitute for a doctor's examination.