First Trimester Symptoms (Weeks 1-12)

Primary drivers: Surge in hCG and progesterone. Expect nausea, fatigue, elevated basal temperature, and frequent urination.

Second Trimester Symptoms (Weeks 13-27)

Primary drivers: Expanding blood volume and uterine weight. Expect round ligament stretching, mild nasal congestion, and skin changes (linea nigra).

Third Trimester Symptoms (Weeks 28-40)

Primary drivers: Mechanical uterine pressure. Expect Braxton Hicks contractions, heartburn, pelvic pressure, and fluid retention.