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Trimester 3 · Week 28 of 40

Week 28 of pregnancy: Third Trimester Begins

The third trimester begins. Go to sleep on your side from now on, ask about anti-D if you are RhD negative, and expect more frequent visits.

Last updated 28 September 2026

What's happening this week?

The third trimester starts this week on this site's count. Your baby weighs roughly a kilogram and is laying down brown fat that will help with warmth after birth. The most important new habit for you is going to sleep on your side, on either side, from now until the birth. This is also a common time for repeat blood tests, for anti-D injections for RhD-negative mothers in some systems, and for antenatal visits to become more frequent.

Baby's development

Your baby's eyes open and close, and periods of activity and rest are becoming more distinct. Brown fat, a special tissue that produces heat, forms mainly from about 26 to 30 weeks and keeps building until birth. It is one reason babies born early find it harder to stay warm, and why they are often cared for in incubators.

The lungs are moving into the saccular stage, which runs roughly from 29 to 36 weeks, when the airspaces that will become air sacs develop further. Surfactant is still immature, and most babies' lungs are ready to breathe unaided only by about 36 weeks. This is why, if a baby looks likely to be born early, the mother may be given steroid injections to help the lungs mature faster.

About 1 in 5 babies are lying bottom-first (breech) at 28 weeks. That is normal at this stage. Most turn head-down by about 36 weeks, and only about 3 to 4 in 100 are still breech at term, so there is nothing you need to do about position now. Your doctor will check again later by feeling your bump; in the UK this is done routinely from 36 weeks.

Your baby's size

About the size of an eggplant

37.6 cm

14.8 in · Length

1000 g

Weight

Week 28

Gestational age

Head-to-heel length is usually in the high 30s of centimetres, and Western reference charts put the middle weight at about 1.2 kg, with a normal range of roughly 0.9 to 1.5 kg. The 1 kg shown sits within that range, and Indian babies are often towards the smaller end. A single scan weight is an estimate, not an exact figure.

Your body this week

Your blood volume is heading towards its peak at around 32 to 34 weeks, and the top of the uterus sits well above your navel. Breathlessness, heartburn and getting up at night to pass urine are common. Ankle swelling that builds through the day and settles overnight is usually expected; sudden swelling of the face or hands is not.

Getting comfortable in bed can become a nightly project. Research, including a large UK study, has linked going to sleep on your back in the third trimester with a higher risk of late stillbirth, so the advice from 28 weeks is to settle down to sleep on your side. Left and right appear equally safe. What matters is the position you fall asleep in: waking up on your back is common, and you can simply turn over.

Tightenings may come more often, and some people notice a little colostrum. Emotionally, the third trimester can bring fresh energy for planning, or a feeling that time is running short; both are normal.

Symptoms you may notice

Every pregnancy is different - you may have some, all or none of these.

Adjusting to side sleeping: It can feel strange if you are used to sleeping on your back. A pillow behind you, one between your knees and one under the bump make it easier. Use the same position for daytime naps.
Breathlessness: Pressure on your diaphragm makes stairs harder. Pause, sit upright and breathe slowly. Breathlessness at rest or with chest pain needs urgent help.
Heartburn: Smaller, more frequent meals and waiting a while before lying down help.
Swollen ankles: Usually worse in the evening and better by morning; put your feet up when you can. Sudden swelling of the face, hands or feet can be a sign of pre-eclampsia and needs checking the same day.
Braxton Hicks tightenings: Often more frequent now, but they should stay irregular and settle with rest. Regular or painful tightenings before 37 weeks need checking straight away.

Medical care and tests

Third antenatal visit (India)
Routine
28–34 weeks
The national minimum of four visits includes one in this window, ideally with a medical officer at a PHC. Blood pressure, weight, urine, haemoglobin and the baby's growth are checked. Many private obstetricians in India now see you every two weeks, as does the traditional US schedule.
Repeat blood tests
Routine
Around 28 weeks
The UK checks a full blood count, blood group and antibodies at the 28-week appointment. In India haemoglobin is rechecked at visits, and the national ANM guideline lists blood grouping at this visit if it was not done earlier. A low haemoglobin can lead to a higher iron dose.
Anti-D for RhD-negative mothers
Varies by provider
Around 28 weeks in the UK; varies elsewhere
If you are RhD negative, anti-D helps stop your immune system forming antibodies that could affect this or a future baby. The UK offers it routinely at 28 weeks to RhD-negative women without antibodies. In India many private and tertiary hospitals give it, but practice varies, so ask your doctor.
Maternal RSV vaccine
Varies by provider
From 28 weeks in the UK; 32–36 weeks in season in the US
Its availability for pregnant women in India is unclear; ask your doctor.

If you first attend antenatal care after 28 weeks in India, one glucose test is done at that first visit. Women with gestational diabetes are advised a growth scan at 28 to 30 weeks.

Nutrition this week

As the uterus crowds your stomach, five or six smaller meals often sit better than three large ones. A mid-morning bowl of vegetable poha, an evening chana chaat or a glass of milk can fill the gaps without overloading you.
Your iron needs stay high as blood volume approaches its peak. Keep taking the iron-folic acid tablet every day, and if your 28-week result shows low haemoglobin, your doctor may change the dose.
Leave at least an hour between tea or coffee and your iron tablet or main meals, since tannins block iron absorption.
If heartburn troubles you at night, eat your evening meal a while before bed and avoid lying down straight after eating.

Movement and exercise

Keep moving most days, adjusting pace to comfort. Walking and swimming are easy on the joints and your back.
Do floor exercises lying on your side or propped up rather than flat on your back, and get up by rolling onto your side first, then pushing up with your arms.
Stop and seek advice if you have bleeding, leaking fluid, regular painful tightenings, dizziness, chest pain or calf pain during exercise.

Things to keep in mind

Set yourself up for side sleeping: arrange pillows before you get into bed, and use them for daytime naps too.
Know your blood group. If you are RhD negative, make sure it is written in your file, and mention it if you have any bleeding or a fall.
Visits usually become more frequent from now, so plan work, childcare and transport around them.
Keep getting to know your baby's pattern of movements; it matters even more in the third trimester.

When to contact your doctor

Call your doctor or midwife the same day if you have

Itching, especially on the palms of your hands or soles of your feet.
Any vaginal bleeding, or a fall or knock to the bump, especially if you are RhD negative.
A headache that does not ease with rest, or swelling that appears suddenly in your face, hands or feet.
Pain, swelling or redness in one calf.
Feeling feverish, with a temperature of 38°C or more.

Get emergency care now if you have

Reduced, changed or absent movements: contact the maternity unit straight away.
Heavy bleeding, or constant severe pain with a hard, tender bump.
Regular tightenings, pelvic pressure or leaking fluid before 37 weeks.
Severe headache with vision changes, or pain under the right ribs.
Chest pain, sudden breathlessness or collapse.

In India, call 108 for an ambulance, 102 for free transport for pregnant women in many states, or 112 for any emergency - or go straight to your nearest hospital with a maternity unit.

If something feels wrong, trust that feeling and call - you never need to wait for your next appointment.

Questions to ask your doctor

What is my blood group, and do I need anti-D?
How often will I be seen from now on?
What did my repeat blood count show?
My scan says my baby is breech; is that a concern at this stage?
Will I be offered a growth scan?

Week 28 checklist

Go to sleep on your side from tonight
Arrange pillows for your back, knees and bump
Confirm your blood group, and ask about anti-D if RhD negative
Book your 28–34 week visit
Note your next appointment dates

Frequently asked questions

Does it matter which side I sleep on?

No. From 28 weeks the advice is to go to sleep on your side, and left and right appear equally safe. The older idea that only the left side will do is not supported by current guidance. Waking up on your back is common; just turn onto your side. Use pillows to stay comfortable, and follow the same advice for daytime naps.

My baby is breech at 28 weeks. Should I worry?

Usually not. About 1 in 5 babies are bottom-first at 28 weeks, and most turn head-down by about 36 weeks. Only about 3 to 4 in 100 are still breech at term. Your doctor will check the position again later in pregnancy and, if needed, discuss options then.

Do all Rh-negative mothers get an injection at 28 weeks?

In the UK, RhD-negative women who have not developed antibodies are routinely offered anti-D at 28 weeks. In India practice varies between hospitals, and we could not confirm a single national rule, so ask your doctor what they recommend. Anti-D may also be needed after bleeding, a fall or a blow to the bump.

This page is general information, not a diagnosis or a substitute for care from your own doctor or midwife. Pregnancies differ, and timings here are typical ranges rather than deadlines. Read our medical disclaimer and editorial policy.