Pregnancy physiology

Uterus is at pubic symphysis at 12 weeks gestation.

Pregnancy is a hyper dynamic state with increased CO and Stroke volume. Systolic murmur may be heard.

Due to increased TBG total thyroid hormones may be higher in pregnancy but the free fraction is normal. TSH is normal.

Minute ventilation increases in pregnancy due to increased tidal volume- NOT respiratory rate. Mild respiratory alkalosis may be present.

GFR increases in pregnancy.

Best measurement to assess fetal gestation by ultrasound in first trimester is crown rump length and in third trimester it is biparietal diameter and femur length.