First Trimester
Week 5: The heart begins beating — about 100 times per minute.
Here's everything happening with your baby and your body this week.
Your baby is the size of a
Sesame seed
Length
0.13 in
Weight
< 1 g
Week
5 / 40
💡 Expert tip
Morning sickness peaks at weeks 6–9. Small, frequent meals and ginger can help. If you can
🌱 Baby's development this week
- Heart tube begins beating
- Brain and spinal cord forming rapidly
- Arm and leg buds appear
- Eyes and ears beginning to develop
Science fact
The heart beats for the first time around day 22 post-conception. By week 5 it
🤰 Your symptoms this week
Morning sickness
affects 70–80% of pregnant women, peaks weeks 6–9
Eat small meals every 2h, keep crackers by the bed, try cold foods (smell less). Severe cases: ask about Diclegis.
Breast tenderness
estrogen and progesterone increasing blood flow
A well-fitting supportive bra helps significantly. Warm compresses can ease discomfort.
Frequent urination
kidneys filtering 50% more blood already
Normal — your kidneys are filtering 50% more blood. Stay hydrated but reduce fluids before bed.
💛 Changes in your body
- Nausea may begin (morning sickness)
- Tender, swollen breasts
- Frequent urination begins
- Fatigue intensifies
💙 Mental health this week
Mood swings are driven by hCG and progesterone — not weakness. Peaks at weeks 6–10 then typically eases.
🥗 Nutrition focus
- Vitamin B6 (10–25mg, 3x daily) significantly reduces nausea — supported by multiple RCTs and recommended by ACOG
- Small meals every 2–3 hours prevent blood sugar dips
- Ginger (tea, chews) reduces nausea — 3 RCTs confirm this
📅 Appointment / test
Book your 8–10 week booking appointment if you haven
✅ This week's checklist
Take prenatal vitamin with food to reduce nausea
Keep plain crackers by the bed for morning queasiness
Avoid strong smells that trigger nausea
Track your pregnancy week by week
Interactive guide · 40 weeks · Fruit size visualizations · Personalized tips
Open Week 5 in Interactive Guide → →