Our Baby JourneyFirst trimester of pregnancy
The first trimester runs from week 1 to week 13. It is when your baby's major organs, spine and heart form, and when many people feel the most tired and nauseous.
Your baby in the first trimester
In just a few weeks a single fertilized egg becomes an embryo with a beating heart, and by the end of week 13 your baby is fully formed in miniature: arms, legs, fingers, toes and all major organs are in place and will now grow and mature.
Common symptoms
- Nausea and vomiting (morning sickness), which can happen at any time of day
- Tiredness and needing more sleep
- Tender, swollen breasts
- Needing to urinate more often
- Food aversions or cravings and a metallic taste
- Mood swings
- Light spotting around implantation
Checkups and things to do
- Book your first prenatal appointment, usually between weeks 8 and 12.
- A dating ultrasound confirms how far along you are and your due date.
- Screening for chromosomal conditions is usually offered between weeks 10 and 14 (blood tests and a nuchal translucency scan).
- Take a prenatal vitamin with at least 400 mcg of folic acid every day.
- Avoid alcohol, smoking and recreational drugs, and limit caffeine to about 200 mg a day.
- Follow food-safety advice: avoid unpasteurized dairy, raw or undercooked meat, eggs and fish, and high-mercury fish.
Timing of scans, tests and vaccines differs between countries, so follow the schedule your healthcare provider gives you.
When to call your doctor or midwife
Contact your healthcare provider or maternity unit straight away, or get emergency care, if you have:
- Vaginal bleeding
- Severe or persistent abdominal pain or cramping
- A severe headache, blurred vision, or sudden swelling of your face, hands or feet
- A fever of 38°C (100.4°F) or higher
- Fluid leaking from your vagina
- Severe vomiting where you cannot keep fluids down
- Your baby moving less than usual or a change in their pattern of movements (later in pregnancy)
- Regular contractions before 37 weeks
- Pain or burning when you urinate
- Feeling very low, anxious, or having thoughts of harming yourself
Week by week
- 🌱 Week 1
- 🌱 Week 2
- 🔬 Week 3
- 🌱 Week 4
- 🌰 Week 5
- 🫘 Week 6
- 🫐 Week 7
- 🍇 Week 8
- 🍒 Week 9
- 🍓 Week 10
- 🟣 Week 11
- 🍋 Week 12
- 🍋 Week 13
General educational information only, not a substitute for advice from your doctor or midwife. 2026-11-07. See our medical disclaimer.