Week 28 starts the third trimester, and it carries the busiest routine appointment of the second half of pregnancy. Repeat blood tests, anti-D if your blood group needs it, and in many systems glucose testing all land in this window. It is also the week side sleeping stops being a comfort tip.
Your body this week
Heartburn and indigestion get worse as the stomach loses space. Backs take strain from the extra weight, and joints and ligaments are looser than usual.
Ankles, feet and face may puff, particularly in hot weather. The NHS says to have it checked rather than assume it is water retention, because pre-eclampsia can develop while you feel perfectly well and then move quickly.
From this week, guidance is to go to sleep on your side. It applies to going to sleep at night, to getting back to sleep after waking, and to daytime naps. Waking up on your back is not a failure; turn over and go back to sleep.
What you may notice
Nosebleeds and indigestion often start or worsen now. Alongside them: sleep problems, stretch marks, sore gums, round ligament pains, piles, headaches, backache, bloating and constipation, leg cramps, feeling hot, dizziness, swollen hands and feet, urine infections, vaginal infections, and skin and hair changes.
Movements should be as strong and as regular as they have been. Any reduction is a call to your maternity unit, day or night.
Your baby this week
Around week 28, the length given is about 37.6cm from head to heel, which the NHS compares to an aubergine. Averages across a population, not a measurement of your own pregnancy.
Heart rate changes across pregnancy: the NHS describes around 110 beats per minute when a heartbeat is first detectable, around 170 at weeks 9 and 10, roughly 140 by now, and around 130 at birth — all faster than an adult's, because small hearts pump less per beat.
What care usually happens around now
In the UK, the 28-week appointment includes blood pressure, urine and bump measurement, plus repeat blood tests that check for anaemia and antibodies. Women who are rhesus D negative are usually offered anti-D in the third trimester, which ACOG explains is about protecting future pregnancies as well as this one.
Screening for gestational diabetes, where it is offered, usually happens between 24 and 28 weeks. ACOG describes it as a routine screening test in that window; in the UK it is offered based on risk factors rather than to everyone. The RSV vaccination is recommended in the UK from around week 28. Which of these apply to you depends entirely on the country and the service.
This week's tip
Ask at this appointment whether you are rhesus D negative, and what that means for your care. It is the one blood result that changes what you are offered for the rest of this pregnancy and the next one, and it is the result most often assumed rather than known.
When to see a doctor
Contact your maternity service the same day for reduced movements, leaking fluid, tightenings that become regular, or bleeding. A headache with vision changes or sudden swelling needs emergency care. Pregnancy warning signs has the 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
What is anti-D for?
It is offered to women whose blood is rhesus D negative, to stop antibodies forming that could affect a future pregnancy. Your midwife will explain what applies to you.
Will I be tested for gestational diabetes?
It depends where you are. Some systems screen everyone between 24 and 28 weeks, others screen on risk factors. Week 29 covers the weeks after, and week 27 closes the second trimester.