Pregnancy & baby

Pregnancy & baby

What happens in each trimester, the common symptoms and how to ease them, the warning signs that always need urgent checking, and clear guides to pregnancy conditions — clinically reviewed and UK/NHS-aligned.

Written by Meds Global Health Clinical Team · Clinically reviewed by Dr Muhammad Suffyan, MB BS, Founder & Clinical Director · Last reviewed · How we review
Tool Due date calculator Estimate your due date, how far along you are and your trimester. Self-assessment Mood check (PHQ-9) A private questionnaire — low mood in pregnancy and after birth is common and treatable.

The three trimesters

Pregnancy is divided into three stages of roughly three months each. Every pregnancy is different — this is a general guide to what many people experience.

Weeks 1–12

First trimester

The pregnancy is confirmed and the baby’s major organs begin to form. Many people feel very tired and have nausea (“morning sickness”, though it can strike at any time), tender breasts and a heightened sense of smell. This is the time to book with a midwife or GP — ideally before 10 weeks — start a daily 400 microgram folic acid supplement (plus vitamin D), and arrange your first “dating” scan.

Keep an eye out: Bleeding, one-sided tummy pain or severe, unrelenting vomiting need prompt checking.

Weeks 13–26

Second trimester

Often the most comfortable stretch: nausea usually settles and energy returns. A bump appears, and many people first feel the baby move (“quickening”) from around 16–24 weeks. The 18–21 week anomaly scan checks the baby’s development. Heartburn, constipation, back pain and mild swelling are common as the body changes.

Keep an eye out: Reduced or changed baby movements once you have felt them, or a sudden increase in swelling, should be checked the same day.

Weeks 27–birth

Third trimester

The baby grows quickly and prepares for birth. Sleep, breathlessness, swollen ankles, stronger Braxton-Hicks (“practice”) contractions and needing to wee often are all common. Your team will monitor blood pressure and growth, talk through your birth plan, and check the baby’s position. Term is anywhere from 37 to 42 weeks.

Keep an eye out: Reduced baby movements, a severe headache with visual disturbance, or waters breaking before 37 weeks need urgent assessment.

When to get help

Call 999 now if…

Call 999 or go to A&E if pregnancy comes with any of these warning signs:

  • Heavy vaginal bleeding, or any bleeding with tummy pain
  • A severe or sudden headache, especially with vision changes, or sudden swelling of the face, hands or feet (possible pre-eclampsia)
  • Your baby moving less, or a change in the usual pattern of movements
  • Severe tummy pain, or one-sided pain that does not ease
  • Your waters breaking before 37 weeks, or a gush/trickle of fluid
  • A high temperature, or feeling generally very unwell
  • A calf that is swollen, red, hot or painful, or sudden breathlessness or chest pain

When to see a doctor

Trust your instincts. If something feels wrong, contact your midwife, maternity unit or GP straight away — day or night. Maternity units are staffed around the clock and would always rather check than have you wait.

999Emergency — call 999 or go to A&E
111Urgent advice — call NHS 111 or use 111 online
GPNon-urgent — see your GP or pharmacist

Not sure how urgent it is? It is always OK to call NHS 111 for advice, day or night.

Pregnancy conditions, explained

Plain-English, clinically reviewed guides to the conditions that can arise in pregnancy and after birth — what they are, how they are managed and when to seek help.

Morning sickness Very common nausea and vomiting in early pregnancy that, despite its name, can happen at any time of day — usually harmless and settling by around weeks 16–20. Pre-eclampsia A pregnancy condition involving high blood pressure and protein in the urine that can become serious for mother and baby — closely monitored, with delivery being the definitive treatment. Gestational diabetes High blood sugar that first appears during pregnancy — usually managed with diet, activity and monitoring, with metformin or insulin added if needed to protect mother and baby. Gestational hypertension High blood pressure that develops during pregnancy, needing monitoring because it can progress to pre-eclampsia — usually managed well with regular checks and treatment. Miscarriage The loss of a pregnancy in the first 23 weeks, most often in the early weeks — common and usually not caused by anything the woman did, with care and support available. Ectopic pregnancy A pregnancy that implants outside the womb, usually in a fallopian tube — a potentially life-threatening emergency that needs prompt diagnosis and treatment. Postnatal depression Depression that develops in the year after having a baby — a common and treatable illness, not a personal failing — managed with talking therapy and, where needed, an antidepressant chosen with breastfeeding in mind, plus support from family and the health-visiting team. Postpartum thyroiditis Inflammation of the thyroid gland in the year after giving birth, causing an overactive then underactive thyroid — often temporary, and important not to mistake for other conditions. Postpartum psychosis A rare but serious mental illness that can develop rapidly after childbirth, causing confusion, mood changes and loss of contact with reality — a medical emergency needing urgent treatment.

Common pregnancy symptoms

Many everyday symptoms are more common in pregnancy as the body changes. These guides explain the usual causes, self-care that is safe to try, and when a symptom needs checking.

Answers

Pregnancy: frequently asked questions

How many weeks pregnant am I?

Pregnancy is counted in weeks from the first day of your last period, not from conception — so you are counted as about “2 weeks pregnant” at conception. Our due date calculator works out your current gestational age and trimester from your last period, a conception date or a dating scan.

When should I first see a midwife?

As early as possible — ideally before 10 weeks in the UK — so your antenatal care, blood tests and first scan can be arranged. You can usually self-refer to your local maternity service or book through your GP.

What supplements are recommended in pregnancy?

In the UK, 400 micrograms of folic acid daily is advised before conception and until 12 weeks (a higher dose for some people — ask your GP), plus 10 micrograms of vitamin D daily throughout pregnancy. Avoid supplements containing vitamin A (retinol). Always check any supplement or medicine with your midwife, GP or pharmacist.

Is this a substitute for antenatal care?

No. This hub is educational and UK/NHS-aligned, but it does not replace your midwife or GP. Anything worrying — bleeding, severe headache, reduced baby movements — should be checked the same day, not left until your next appointment.

Work out your due date

Estimate your baby’s due date, gestational age and trimester in seconds — privately, in your browser.

Due date calculator ☎ +44 7448 439750
☎ Call Get a Proposal