For these reasons, many women may not know that they're pregnant until around six weeks into their pregnancy. And "pregnancy," as calculated by medical professionals, starts on the first day of your last menstrual cycle — if an egg is fertilised. "The development of pregnancy is counted from the first day of the woman’s last normal menstrual period (LMP), even though the development of the foetus does not begin until conception, which is about two weeks later," explains the American Pregnancy Association. That's why pregnancies technically last 40 weeks or 10 months, instead of the more popularly known nine months. So, an abortion cut off date around the same time that most people would even be discovering that they're pregnant is ignoring "basic biology" as Ocasio-Cortez wrote . Furthermore, most foetal heartbeats aren't even detectable until closer to between eight and 10 weeks