When talking about weeks of gestation or pregnancy, it is usual to start counting from the date of the beginning of the last menstrual period (LMP) or, in other words, from the beginning of the last menstrual cycle.
This is because, normally, the woman does not know the exact day on which fertilization occurred. However, it is easy for the expectant mother to know when her last menstrual period was.
Read the full article on: The first month of pregnancy: initial symptoms and maternal care ( 79).
By Blanca Paraíso M.D., Ph.D., M.Sc. (gynecologist), Carmen Ochoa Marieta M.D., Ph.D., M.Sc. (gynecologist), Daniel Sosa M.D., M.Sc. (gynecologist), Silvia Azaña Gutiérrez B.Sc., M.Sc. (embryologist), Zaira Salvador B.Sc., M.Sc. (embryologist), Michelle Lorraine Embleton B.Sc. Ph.D. (biochemist) and Cristina Algarra Goosman B.Sc., M.Sc. (psychologist).
Last Update: 08/19/2022