Women possess various hormones that regulate their sexual maturity, their ability to reproduce, and their ability to produce breast milk. Feminine hormones dictate womanhood.
Hormonal systems can be broken down into their functions: fertility (the 28 day menstrual cycle), pregnancy, and milk production. A couple of hormones are involved in all of these processes.
Estrogen is the main sex hormone in females. It is largely produced by the ovaries, or female gonads. During pregnancy, the placenta also produces it.
Estrogen is responsible for sexual maturity in women. It stimulates breast and hip development and fat distribution in these areas.
Estrogen also causes the sexual organs to mature and be able to reproduce. During the first half of the menstrual cycle, it causes the endometrium in the uterus to thicken and accept an embryo. After conception, it allows the body to maintain a pregnancy .
Progesterone is the hormone that maintains the thickened endometrium after ovulation (or the releasing of a monthly egg.) Progesterone causes the endometrial lining to further thicken and grow stronger to accept an embryo. The rise in estrogen and progesterone levels is the reason for monthly PMS.
During pregnancy, progesterone and estrogen help to maintain the fetus. They cause an increase in blood circulation to the uterus and the breasts.
FSH is responsible for the monthly development and release of a ripe egg. It causes an egg to develop within an ovary, and then be released into one of the fallopian tubes (around day 14.)
LH allows a released egg to further develop and wait for fertilization. This happens after ovulation during the second half of the menstrual cycle. LH also causes the ripe egg to produce progesterone. Hence, estrogen and FSH are important during the first half of the menstrual cycle, and progesterone and LH further the groundwork for fertilization.
HGC is a pregnancy hormone that is produced from the placenta after fertilization occurs. It is the hormone that is detected in pregnancy tests. HGC alerts the ovaries to maintain higher levels of estrogen and progesterone production to sustain a pregnancy.
During pregnancy, high levels of estrogen and progesterone signal the breasts to produce milk. Prolactin causes the milk production in the breasts and the moving of that milk to the ducts. Oxytocin causes contractions in the breast to "let down" or release the milk through the nipple. Oxytocin also causes the uterus to contract and return to its normal shape and size after delivery.
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