Overview of the 3 Trimesters

A full-term human pregnancy spans approximately 40 weeks (280 days), structured into three distinct physiological windows:

1. First Trimester (Weeks 1-12)

Focuses on embryo implantation, neural tube formation, early organ development, and primary prenatal screening.

2. Second Trimester (Weeks 13-27)

Focuses on fetal anatomical growth, movement detection, anatomy scan evaluation, and glucose screening.

3. Third Trimester (Weeks 28-40)

Focuses on rapid fetal weight gain, lung maturation, kick count tracking, and labor preparation.