Gestational age

Gestational age is counted in weeks, conventionally from the first day of the last menstrual period. After IVF it is calculated from the date of egg collection or transfer and the embryo's stage, which is more accurate than a period date. This is why a pregnancy is described as around four weeks at the time of a positive test.

Also known as: how many weeks pregnant, weeks pregnant

Last reviewed: 8 September 2026. Written by the Antega Editorial Team. General information only — always follow the advice of your own clinic, doctor or pharmacist.