The placenta primarily secretes human chorionic gonadotropin (hCG).
Understanding Human Chorionic Gonadotropin (hCG)
hCG is a hormone that is almost exclusively produced during pregnancy. Specifically, it is made by the placenta, the organ that develops in the uterus to nourish the growing fetus. This hormone plays a critical role in maintaining pregnancy, especially during the early stages.
Key Roles of hCG:
- Maintaining the Corpus Luteum: hCG helps maintain the corpus luteum, which is a temporary endocrine gland in the ovaries that produces progesterone. Progesterone is vital for sustaining the uterine lining during pregnancy.
- Early Pregnancy Indicator: hCG levels in the mother's blood and urine dramatically increase during the first trimester. This increase makes hCG a reliable marker for pregnancy, and it's the hormone detected by pregnancy tests.
- Contributing to Morning Sickness: Elevated hCG levels during early pregnancy are believed to contribute to the nausea and vomiting, often referred to as "morning sickness," that some women experience.
hCG Production Timeline:
| Stage | hCG Levels |
|---|---|
| Early Pregnancy | Rapidly increasing, highest levels during the first trimester. |
| Later in Pregnancy | Levels plateau and eventually decline as the placenta matures. |
| After Delivery | hCG levels rapidly decrease and return to non-pregnancy levels. |
Clinical Significance:
- Pregnancy Tests: Most home and clinical pregnancy tests detect the presence of hCG in urine or blood.
- Monitoring Pregnancy: Doctors may monitor hCG levels to track the progress of early pregnancies. Deviations from expected patterns can indicate potential problems.
- Tumor Marker: In some rare cases, non-pregnancy related tumors can produce hCG. This can be used as a tumor marker.
In summary, while the placenta produces multiple hormones vital for a healthy pregnancy, hCG is the key hormone that is most significantly associated with the placenta's function and pregnancy detection.
