Pregnancy and postpartum dynamics revealed by millions of lab tests

Pregnancy and delivery involve dynamic alterations in many physiological systems. However, the physiological dynamics during pregnancy and after delivery have not been systematically analyzed at high temporal resolution in a large human population. Here, we present the dynamics of 76 lab tests based on a cross-sectional analysis of 44 million measurements from over 300,000 pregnancies. We analyzed each test at weekly intervals from 20 weeks preconception to 80 weeks postpartum, providing detailed temporal profiles. About half of the tests take 3 months to a year to return to baseline postpartum, highlighting the physiological load of childbirth. The precision of the data revealed effects of preconception supplements, overshoots after delivery and intricate temporal responses to changes in blood volume and renal filtration rate. Pregnancy complications—gestational diabetes, preeclampsia, and postpartum hemorrhage—showed distinct dynamical changes. These results provide a comprehensive dynamic portrait of the systems physiology of pregnancy.