The placenta forms a crucial connection between a fetus and the mother. Throughout the pregnancy, it supports all the biological functions that fetuses can’t do for themselves yet. After attaching to the uterine wall, the placenta connects to the growing fetus via the umbilical cord. Here are the functions of the placenta:
- Supplies nutrients and oxygen – The placenta delivers nutrients, supplies oxygen, and transfers carbon dioxide from the baby to the mother’s blood supply.
- Provides maternal hormones – Certain regulators such as thyroid hormones are necessary for the baby’s growth and development before their thyroid begins to function.
- Eliminates waste – Waste produced by the fetus, such as urea, uric acid, and bilirubin, is absorbed into the mother’s blood via the placenta through a process called diffusion.
- Produces pregnancy hormones – The placenta produces many hormones throughout pregnancy, each of which plays an important role in supporting your pregnancy.
– Human chorionic gonadotropin (hCG) maintains the corpus luteum — an important temporary gland in the ovaries, which produces progesterone until the placenta takes over. If you don’t become pregnant, this structure sheds every month a few days after ovulation, causing menstruation. If you do become pregnant, the hCG produced by the placenta tells the corpus luteum to sustain the pregnancy, maintain the uterine lining, release hormones, and more. This is why hCG is the hormone detected by pregnancy test kits.
– Progesterone supports the implantation of the fetus and creates a rich uterine lining of blood vessels to provide nutrition to the baby. It also keeps the uterine muscles relaxed, which helps maintain pregnancy.
– Estrogen promotes breast and milk duct development in a pregnant person. It promotes metabolic changes during pregnancy, influences insulin level, and reduces appetite.
– Human placental lactogen (hPL) stimulates the fetus’s growth and development. It promotes breast development and prepares for lactation.
- Provides immunity – The body’s infection-fighting antibodies, called immunoglobulins (mostly IgA and IgG), can pass to the fetus through the placenta. Antibodies protect against infections while the fetal immune system develops. Because the concentration of maternal antibodies peaks by the time of delivery, term babies are less prone to infections than premature babies. Parental antibodies also protect the baby for around three months after delivery.
- Filters out microorganisms – The placenta creates a barrier between the mother and the fetus. Although the placenta can filter some infectious agents, it is not a perfect barrier. That’s why health care providers tell pregnant people to avoid possible sources of infection and toxins (e.g., nicotine, alcohol, and drugs).
- Regulates the baby’s body temperature