The Third Trimester: What to Expect

The home stretch is here. From week 28 until your baby arrives, your body and your baby are both doing a lot of growing and preparing. You may feel proud, tired, excited, and uncomfortable all in the same hour. That is normal. This guide walks you through what is happening week to week, the symptoms most parents notice, how to keep an eye on your baby's movements, the tests and prep coming up, and the early signs that labor is on its way. Every pregnancy is different, so treat this as a map, not a checklist, and lean on your own provider for anything specific to you.

What is happening from weeks 28 to 40

The third trimester begins at 28 weeks and lasts until you give birth, usually around 40 weeks (NHS). This is mostly about growth and finishing touches. Your baby is putting on weight, the lungs and brain are maturing, and the once see-through skin is filling out.

By now your baby is running out of room, so the movements you feel often change. Instead of big rolls, you may notice sharper jabs, stretches, and hiccups. A few practical things shift on your side too:

• Your prenatal visits usually get more frequent, often every two weeks and then weekly as you get close to your due date.
• A "full term" pregnancy is 39 weeks and beyond, and most babies arrive between 37 and 42 weeks.
• Your due date is an estimate. Very few babies arrive exactly on it, so try not to fixate on a single date.

Common late-pregnancy symptoms

Most third-trimester symptoms are uncomfortable but normal. The NHS lists heartburn and indigestion, swelling in the feet, ankles, and face, trouble sleeping, leg cramps, and back strain as common in these weeks (NHS). You may also notice shortness of breath as your uterus presses up under your ribs, plus more frequent trips to the bathroom as your baby drops lower.

Braxton Hicks vs real contractions

Many parents feel Braxton Hicks contractions, sometimes called practice contractions. They feel like a tightening across your bump that comes and goes, and they should not be painful or settle into a regular pattern. Real labor contractions tend to get longer, stronger, and closer together over time. If you are not sure which you are having, that is exactly the kind of thing to call your provider about.

Keeping an eye on your baby's movements

Getting to know how your baby moves is one of the most useful things you can do in the third trimester. Here is the key point: there is no set number of movements you should feel each day, because every baby is different. What matters is learning your baby's usual pattern from day to day (NHS).

You may notice your baby is busier at certain times, like after you eat or in the evening when you finally sit down. That rhythm is your baseline. A change in that pattern, especially movements slowing down or stopping, is the thing to act on.

The NHS is clear here: call your midwife or maternity unit immediately if your baby is moving less than usual or you cannot feel your baby moving anymore. Do not wait until the next day, even if it is the middle of the night (NHS). It is always okay to get checked. Providers would much rather see you and reassure you than have you wait at home worrying.

Tests and prep before baby comes

A few things tend to happen in these final weeks.

Group B strep (GBS) testing

Around weeks 36 and 37, you will likely be offered a group B strep test. GBS is a common bacteria that comes and goes naturally, which is why testing is done late in pregnancy, close to delivery. A provider rubs a sterile swab on your vagina and rectum, and it is quick and painless (CDC).

A positive result does not mean you are sick. It just means the bacteria are present. If you test positive, you will be offered antibiotics through an IV during labor to protect your baby (CDC). That is one reason to head to your birth place promptly once labor starts.

Packing your hospital bag

Aim to have a bag ready by about 36 weeks, just in case your baby comes early. Most parents pack:

• ID, insurance details, and any birth paperwork
• A phone charger with a long cord
• Comfortable, loose clothes and a robe
• Toiletries, lip balm, and hair ties
• Snacks and a refillable water bottle
• A going-home outfit for you and for your baby
• An approved car seat, installed in the car ahead of time

You may also want nursing supplies, postpartum pads, and a feeding pillow, depending on your plans.

Early signs that labor is starting

Labor can build slowly, so the early signs are worth knowing. According to the NHS, common signs that labor has begun include contractions or tightenings, a "show" when the plug of mucus from your cervix comes away, backache, an urge to use the toilet caused by your baby's head pressing on your bowel, and your waters breaking (NHS).

Many providers suggest staying home in early labor until your contractions are regular and frequent, often coming every 5 minutes or more often. But some situations mean you should call straight away rather than wait.

When to talk to your pediatrician or provider

Milestone ranges and due dates are wide, and most discomfort in these weeks is normal. Still, you know your body and your baby better than anyone. Reach out to your provider if your baby's movements change, if you have severe or sudden swelling, a bad headache, vision changes, or upper belly pain, if you have any bleeding or fluid leaking, or if you just feel that something is off. Asking a question is never a bother. The closer you get to your due date, the more your care team expects to hear from you, so do not hesitate to pick up the phone.