Trimester-by-trimester guide

Pregnancy is usually split into three trimesters, each with its own changes for you and your baby. Here's a gentle overview of what to expect, and what's worth thinking about, at each stage.

First trimester (weeks 1-12)

A huge amount happens in these early weeks, even though there's not much to see on the outside. From a tiny cluster of cells, your baby develops a beating heart, the beginnings of a brain and spinal cord, and little limb buds. By the end of week 12 they're recognisably a tiny person, roughly the size of a plum.

For you, this stage can bring tiredness, tender breasts, and nausea that, despite the name, doesn't always stick to mornings. Some people feel wonderful and some feel rotten; both are normal. Key things to do: start taking 400µg of folic acid (if you haven't already), register your pregnancy with your GP or midwife, and look forward to your dating scan at around 12 weeks.

Second trimester (weeks 13-26)

Often called the "golden" trimester, this is when many people start to feel more themselves again. Early nausea tends to ease, energy returns, and a bump begins to show. Somewhere between weeks 16 and 24 you may feel those first flutters of movement.

Your baby grows quickly, developing hearing, sleep-and-wake cycles, and a coating of fine hair and protective vernix. The big appointment here is the anomaly scan at around 20 weeks, a detailed check of baby's growth and development where you may be able to find out the sex. This calmer window is also the ideal time to research the bigger purchases and plan maternity leave.

Third trimester (weeks 27-birth)

The final stretch. Your baby puts on weight, their lungs and brain mature, and they usually settle into a head-down position ready for birth. You'll likely have more frequent antenatal checks now, plus conversations about your birth plan, feeding and what to expect in labour.

Physically, this trimester can feel demanding, backache, broken sleep, heartburn and a need to nest are all common. Practical jobs come into focus: fitting the car seat, packing your hospital bag, and getting the first-size essentials ready. From 37 weeks your baby is considered term, so it's worth being prepared a little ahead of your due date.

A note on appointments

The schedule above follows the typical UK NHS antenatal pathway, but yours may differ depending on whether it's your first baby and your individual circumstances. Your midwife will guide you on exactly what to expect and when.

This is general information, not medical advice. Always follow the guidance of your own midwife or GP, and see nhs.uk/pregnancy for trusted, up-to-date information.