How long is baby in womb if timed from two weeks before egg fertilized?

It is not possible for a baby to be in the womb if the time is measured from two weeks before the egg is fertilized. Conception, which is the fertilization of an egg by sperm, marks the beginning of pregnancy. Pregnancy typically lasts for about 40 weeks, or nine months, from the first day of a woman's last menstrual period (LMP).