Final answer:
A loss or termination before 20 weeks of gestation is referred to as a miscarriage, which is the spontaneous end of a pregnancy and is different from stillbirth, ectopic pregnancy, and preterm birth.
Step-by-step explanation:
A loss or termination before 20 weeks gestation is referred to as a miscarriage. Miscarriage is a term used when there is a spontaneous termination of an existing pregnancy, usually occurring very early in the pregnancy, within the first few weeks. This typically occurs when the fetus cannot develop properly, resulting in the natural termination of the gestation. In contrast, a stillbirth refers to the loss of a fetus after 20 weeks of gestation. An ectopic pregnancy is a condition where the embryo implants outside the uterus, commonly in the fallopian tubes, and a preterm birth is when a baby is born before 37 weeks of gestation.
Fetal viability, the point at which the fetus is likely to be able to survive outside the uterus, is an important aspect to consider when discussing the chances of survival of preterm infants. Laws regulating abortion, which is the voluntary termination of a pregnancy, often consider fetal viability when determining legality. Infertility is a separate issue, which refers to the inability to conceive or carry a pregnancy to term, and can be caused by a variety of factors including diseases, malnutrition, stress, toxins, and aging.