Week-by-Week Fetal Development and Maternal Health Guide

Once pregnancy is confirmed, the first questions are usually how far along am I? and how is my baby developing? Over 40 weeks, the fetus grows from a single cell into a baby weighing about 3kg, while the mother's body undergoes significant changes.

This guide provides a detailed look at week-by-week fetal development and maternal health management tips for each stage.

First Trimester (Weeks 1-12)

The first trimester is the most critical period as major organs form. The brain, heart, and spinal cord develop during this time, requiring extra care.

Second Trimester (Weeks 13-27)

The second trimester is the stable period. Morning sickness subsides and you feel the baby's first movements.

Third Trimester (Weeks 28-40)

As delivery approaches, the fetus gains weight rapidly while lungs and brain reach final maturation.

• Week 28: ~1kg, can blink eyes
• Week 32: ~1.8kg, lung surfactant production begins
• Week 36: ~2.5kg, most organs mature
• Week 40: ~3.0-3.5kg, ready for delivery

Maternal Weight Management

Appropriate weight gain is important for both mother and baby.

Essential Checkup Schedule

Nutrition by Trimester

Key nutrients vary by pregnancy stage:

• First Trimester: Folic acid 600mcg/day — prevents neural tube defects
• Second Trimester: Iron 30mg/day — supports increasing blood volume
• Third Trimester: Calcium 1,000mg/day — supports fetal bone development
• Throughout: DHA 200mg/day — essential for fetal brain development

Maintain a balanced diet and consult your doctor about supplements. Provide adequate nutrition while preventing excessive weight gain.