Pregnancy

First Trimester: Weeks 1-12 Guide

The first trimester is when the foundations of your baby's development are laid. Here's what to expect, which tests are done, and what symptoms are normal.

Duration
Week 1-12
Booking appointment
By 10 weeks ideally
Dating scan
11-14 weeks
Miscarriage risk
Highest in this trimester

Common Symptoms

The Booking Appointment

What HappensPurpose
Full medical and family historyIdentify risk factors needing extra care
Blood pressure and urine checkBaseline for later comparison
Blood tests (FBC, blood group, rhesus status, infections)Screen for anaemia, blood group incompatibility, infections
Down's syndrome screening discussionCombined test (11-14 weeks) or later alternatives
Weight and BMIBaseline; guides risk assessment

The Dating Scan (11-14 weeks)

This ultrasound confirms how many weeks pregnant you are, checks for multiple pregnancy (twins), and measures nuchal translucency (part of Down's syndrome screening if opted for).
When to Seek Urgent AdviceHeavy bleeding, severe abdominal pain, fever, or severe unrelenting vomiting — always contact your midwife, maternity unit, or GP promptly. First trimester bleeding is common (affects 1 in 4 pregnancies) but should always be checked.
Folic Acid and Vitamin DContinue folic acid (400mcg, or 5mg if higher risk) until 12 weeks to reduce neural tube defect risk. Vitamin D (10mcg) is recommended throughout pregnancy. Avoid vitamin A supplements and liver (contains high vitamin A, which can harm the baby).
Is spotting normal in early pregnancy?
Light spotting affects up to 25% of pregnancies and is often not concerning, but always report any bleeding to your midwife for assessment, as it can occasionally indicate miscarriage or ectopic pregnancy.
When should I tell people I'm pregnant?
This is a personal choice — many wait until after the 12-week scan when miscarriage risk drops significantly, but there's no medical requirement to wait.
What foods should I avoid?
Unpasteurised soft cheese, pâté, raw or undercooked eggs/meat, liver, excess caffeine (<200mg/day), and alcohol (avoid completely) are the main foods to avoid throughout pregnancy.
Medical Disclaimer: This page is for general education only and does not replace professional medical advice. Always consult a qualified healthcare provider.