First Trimester6 min read

Your Guide to the First Trimester of Pregnancy

The first trimester brings exciting news and significant changes to your body. Here's what to expect during weeks 1–12 of pregnancy, plus practical tips to help you feel your best.

Bubsworth Editorial Team

Reviewed for accuracy against NHS and NICE guidelines. Updated 1 April 2026.

Key Facts

  • The first trimester runs from week 1 to week 12 of pregnancy
  • Morning sickness affects about 80% of pregnant women, though it can happen any time of day
  • Your first antenatal appointment (dating scan) usually happens around 8–12 weeks
  • Folic acid supplementation (400mcg daily) is recommended throughout the first trimester

What Happens During the First Trimester

The first trimester is a period of rapid development for your baby and significant change for your body. Your baby grows from a single cell to roughly 5cm long, with a heartbeat that can be detected by around 6 weeks. Meanwhile, your body is producing pregnancy hormones that trigger a cascade of physical and emotional changes. You might notice your breasts feel tender, you're more tired than usual, or you're experiencing mood swings. These are all completely normal responses to the hormonal shifts happening inside you. It's worth remembering that every pregnancy is different - what happens to your friend might not happen to you, and that's perfectly fine.

Managing Common Early Pregnancy Symptoms

Morning sickness is one of the most talked-about symptoms, though it often lasts all day. If you're struggling, try eating small, frequent meals, staying hydrated, and keeping ginger biscuits by your bed to nibble before getting up. Fatigue is equally common - your body is working incredibly hard, so rest when you can. Avoid caffeine where possible, and aim for 8–10 hours of sleep nightly. Tender breasts, constipation, and food cravings or aversions are also par for the course. If you're worried about any symptom, contact your GP or midwife rather than suffering in silence.

Nutrition and Lifestyle

Taking folic acid (400mcg daily) is crucial during the first trimester, as it reduces the risk of neural tube defects. You'll find it in fortified cereals, leafy greens, and pulses, though a supplement ensures you're getting enough. Eat a balanced diet with plenty of fruits, vegetables, protein, and wholegrains. Avoid high-risk foods like unpasteurised dairy, undercooked meat, and raw eggs (the NHS has a full list on their website). Gentle exercise is fine - walking, swimming, and pregnancy yoga are brilliant. Avoid strenuous activity without checking with your midwife first. It's also the right time to cut out alcohol completely and avoid smoking.

Your First Antenatal Appointments

Your GP will refer you to your local maternity service, where you'll have your booking appointment (usually around 8–10 weeks). This is followed by your dating scan around 11–14 weeks, which confirms your due date and checks your baby's development. Don't worry if you're anxious about these appointments - it's completely natural. The scan is a wonderful opportunity to see your baby and hear their heartbeat. You'll also have blood tests to check your blood group, anaemia levels, and screening for infections. Write down any questions beforehand so you don't forget them during the appointment.

Emotional Changes and Self-Care

Pregnancy hormones can affect your mood significantly, and it's common to feel anxious, emotional, or overwhelmed. These feelings are valid and very normal. Talk to your partner, friends, or midwife about how you're feeling. Many NHS services offer free antenatal classes and support groups where you can meet other expectant parents. Remember to be kind to yourself during this transformative time. Rest when you need to, ask for help, and don't feel pressured to keep your pregnancy private until you're ready to share the news. If you experience persistent low mood or anxiety, discuss it with your GP - support is available.

When to Contact Your Midwife or GP

Most first-trimester pregnancies progress beautifully, but certain symptoms warrant professional advice. Contact your midwife or GP if you experience heavy vaginal bleeding, severe abdominal pain, persistent vomiting, signs of infection (high temperature), or loss of pregnancy symptoms. You can also call your maternity unit directly if you're worried about anything - they're used to expectant parents' concerns and would rather you check in than stress alone. Having these contact numbers saved in your phone from the start can provide reassurance.

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