Final answer:
Progesterone levels below 5 ng/mL often indicate a nonviable pregnancy, while levels above 25 ng/mL suggest a normal and viable pregnancy. Progesterone's role in reducing uterine contractions and supporting fetal health is critical early on, but levels decrease to allow for labor in late pregnancy. The placenta takes over hormone production as the pregnancy progresses.
Step-by-step explanation:
The correct levels of progesterone concentration related to pregnancy viability are important for determining whether a pregnancy is intrauterine (within the uterus) or extrauterine (outside the uterus), as well as whether it is viable or nonviable. While specific cutoffs can vary somewhat depending on different medical sources, a general guideline is that a progesterone concentration of < 5 ng/mL typically suggests a nonviable pregnancy or an abnormal pregnancy, such as an ectopic pregnancy, while levels of > 25 ng/mL suggest a normal, viable pregnancy. These levels help in assessing the risk of miscarriage and the need for potential interventions.
Progesterone is known to suppress uterine contractions and support the health of the fetus by preventing preterm birth early in the gestation. However, as the pregnancy progresses, specifically in the late gestation period, progesterone levels decrease, and contractions intensify leading to true labor. Furthermore, the placenta assumes the role of the endocrine organ of pregnancy, secreting hormones that are critical to maintaining pregnancy after the corpus luteum degenerates.