On June 24, 2022, the US Supreme Court overturned abortion rights. We are updating this fact sheet as states implement and enforce abortion bans.
Last menstrual period (LMP): The beginning of pregnancy calculated from the start of the most recent menstrual period. An average pregnancy lasts approximately 40 weeks from this point.
Postfertilization: The beginning of pregnancy calculated from the date of conception; 20 weeks postfertilization is equivalent to 22 weeks LMP.
Postimplantation: The beginning of pregnancy calculated from the date of embryo implantation; 24 weeks postimplantation is equivalent to 27 weeks LMP.
General health: Defined by an individual doctor and includes the patient’s mental and emotional health.
Physical health: Applies only to the physical function of the patient’s body and may even be restricted to major bodily functions.
Viability: The point at which a fetus can sustain survival outside the uterus. Determined based on the fetus’s developmental progress and may vary by pregnancy. A fetus generally reaches viability between 24 and 28 weeks LMP.