First Trimester
4 Weeks Pregnant
Your baby is the size of a Poppy seed 🔴
🔴
Medically reviewed by
MBBS, MD — Gynecologist & Obstetrician
Last reviewed:
Feb 2026
📏
Size
Poppy seed
📐
Length
0.2 cm cm
⚖️
Weight
NaN g
🗓️
Trimester
First
⏱️
Week
4 of 40
🌱 Baby Development at Week 4
Implantation in the uterine wall occurs. The embryo is now made of three layers: ectoderm, mesoderm, and endoderm — each becoming different body systems. A home pregnancy test may now be positive.
Implantation completePositive pregnancy test possibleThree germ layers form
🤱 Common Symptoms
●Missed period
●Breast tenderness
●Fatigue
●Slight nausea beginning
●Frequent urination
🥗 Nutrition Tips
- Increase folic acid to 600mcg if pregnant
- Eat small frequent meals
- Ginger tea for early nausea
🏃♀️ Exercise Tips
- Gentle walking and yoga fine
- Avoid hot tubs and saunas
- Listen to your body
🏥 Medical Tests & Appointments
Home pregnancy testSchedule first OB appointment
🔬 Hormone Changes
hCG doubles every 48-72 hours. Progesterone rises significantly. Home pregnancy tests can now detect hCG.
Frequently Asked Questions
Common questions answered by our medical team