Placental Hormones and Pregnancy — NEET Biology
✅ Asked in NEET 2018After implantation, finger-like projections appear on the trophoblast called chorionic villi which are surrounded by the uterine tissue and maternal blood. The chorionic villi and uterine tissue become interdigitated with each other and jointly form a structural and functional unit between developing embryo (foetus) and maternal body called placenta. The placenta facilitate the supply of oxygen and nutrients to the embryo and also removal of carbon dioxide and excretory/waste materials produced by the embryo. The placenta is connected to the embryo through an umbilical cord which helps in the transport of substances to and from the embryo. Placenta also acts as an endocrine tissue and produces several hormones like human chorionic gonadotrophin (hCG), human placental lactogen (hPL), estrogens, progestogens, etc. In the later phase of pregnancy, a hormone called relaxin is also secreted by the ovary. Let us remember that hCG, hPL and relaxin are produced in women only during pregnancy. In addition, during pregnancy the levels of other hormones like estrogens, progestogens, cortisol, prolactin, thyroxine, etc., are increased several-folds in the maternal blood. Increased production of these hormones is essential for supporting the fetal growth, metabolic changes in the mother and maintenance of pregnancy.
NTA tests your knowledge of hormones produced during pregnancy, especially those uniquely made only during pregnancy (hCG, hPL, relaxin). Students often confuse which hormones are produced by the placenta versus the ovary, or forget that some hormones like estrogen and progesterone exist normally but increase dramatically during pregnancy. The key trap is mixing up placental hormones (hCG, hPL, estrogens, progestogens) with ovarian hormones (relaxin). Remember: hCG and hPL are exclusive to pregnancy and produced by placenta; relaxin is produced by ovary only during pregnancy; other hormones just have increased levels. This concept has appeared twice because hormone regulation during pregnancy is fundamental to understanding human reproduction.
This paragraph was tested 2 times in NEET.
Hormones secreted by the placenta to maintain pregnancy are:
[NEET 2016 Phase 2] Several hormones like hCG, hPL, estrogen, progesterone are produced by:
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