First Trimester
Pregnancy Week 5
Your baby is about the size of a sesame seed 🫘 — heart begins to beat.
🫘
Size comparison
≈ Sesame seed
Length
0.2 cm
Weight
0 g
Milestone
Heart begins to beat
About 35 weeks to go until your due date (week 40).
Baby's development at week 5
A tiny heart is forming and will begin beating this week. The neural tube — which becomes the brain and spinal cord — is also closing.
Eat small, frequent meals to ease nausea and keep energy steady.
Common symptoms at week 5
Morning sickness may beginFrequent urinationFatigueFood aversions
Eat more of
- ✓Folic acid (leafy greens, fortified cereals)
- ✓Iron-rich foods (lentils, spinach)
- ✓Calcium (dairy, fortified plant milk)
- ✓Vitamin B6 (bananas, avocados)
- ✓Whole grains
Foods to avoid
- ✕Alcohol
- ✕Raw/undercooked meat or fish
- ✕High-mercury fish (shark, swordfish)
- ✕Unpasteurised dairy
- ✕Excess caffeine (>200 mg/day)
- ✕Raw sprouts
Medically reviewed by First OPD Medical Team. Last reviewed on .
Based on average milestones from World Health Organization (WHO), ACOG, NHS UK. Educational only — not a substitute for personalised medical advice.
Track every week with a free First OPD account
Save your personalised week, get your due date, and book gynaecologists near you.