A full-term pregnancy, timed from conception, lasts approximately how many days?

1. Pregnancy duration can be measured either from conception or from the last menstrual period (LMP). 2. From conception, A specific full-term duration. 3. That duration is approximately 270 days, or about 38.5 weeks. 4. Because conception is harder to pinpoint clinically, obstetricians instead use 284 days from the LMP to set the due date. _Source: OpenStax Anatomy and Physiology (CC BY 4.0), Ch 28 "Development and Inheritance", p.1341-1342 §Maternal Changes During Pregnancy, Labor, and Birth_