Although our level of knowledge about the benefits of the progesterone hormone, which has very important tasks in the monthly menstrual cycle and early pregnancy stage in the women, especially in IVF treatments is increased today, there are still misconceptions regarding the use of it.
Progesterone hormone is released from the follicle structure, which is emptied after the movement of the mature egg by leaving the ovary towards oviduct the realization of the fertilization process, within natural menstrual cycle and this is known as “cracking” or “ovulation” among people. The medical name of this structure is “corpus luteum”. If fertilisation occurs, progesterone released from this structure supports the formation of new blood vessels in the uterus, supports the implantation of the embryo into the uterus and development of the embryo by providing the release of the necessary materials for the embryo via stimulation of the cells in the uterus. Progesterone is released by the corpus luteum until the formation of placenta (gestational sac); and it is started to be released by the placenta after the formation of placenta by (approximately 12th week of pregnancy)
Progesterone also supports the development of the mother’s breast tissue during pregnancy. The hormone level increasing slowly until the delivery, and decreases suddenly with the delivery. This rapid decrease in progesterone level also triggers the onset of milk production. Progesterone is also called as “pregnancy hormone” because of its effects on the baby’s development in the womb.
Other known effects of the progesterone hormone before pregnancy also includes:
It makes the uterus ready for the implantation of the embryo by putting it into secretory phase. Also, prevents the passage of sperm through its effects on vaginal tissue and mucus formation during the formation of pregnancy,
It promotes the formation of the pregnancy by suppressing the immune system during the implantation of the embryo and pregnancy,
It slows the contraction of the muscles of the uterus during pregnancy,
Although it is not exactly known how it works, it is thought that the sperm benefit from the features of the progesterone hormone in order to reach the egg.
Progesterone hormone levels and effects
High progesterone levels measured in blood has no known serious side effects. It is already known to have high levels naturally during pregnancy. However, if the endogenous (produced by the body) progesterone level examined on the day of egg cracking injection or before during IVF treatment is high, it is shown that the pregnancy rates increase by postponing the transfer in the treatment.
Progesterone can be used as birth control pills alone or in combination with estradiol. It provides the prevention of pregnancy by up to 100% by preventing ovulation. In addition, it may be used to reduce the effects of menopause in women for hormone therapy.
Low or fluctuating levels of progesterone causes irregular menstrual bleeding. The rapid decrease in level during pregnancy can cause miscarriage of the baby or premature birth. Thus, progesterone supplementation is used during miscarriage threat.
The use of progesterone during IVF
The use of progesterone is started on the day of egg collection (the day of egg cracking) the aim of establishing positive effects providing pregnancy on the uterus during IVF procedures and will be continued until the 12th week. How long to use the medication and when to stop it is determined by checking the level of progesterone in the blood. In particular, the transition of the medications to the blood is controlled by controlling its levels in the blood a few days after the transfer procedure. If the transition of the medication to the blood is low, the dose or type of the medication used can be changed (needle, gel or pill).
Progesterone levels and its effect on the day of embryo transfer
The day of embryo transfer cannot be determined by measuring the level of progesterone. Progesterone level measurements performed on certain days of the treatment only help to give a decision in regards to perform the transfer or not in the treatments that fresh or frozen embryo transfer is planned. Other than that, there is no known guidance of progesterone measurement. In other words, expected intrauterine changes can be analysed and possible cases to prevent pregnancy can be detected by measuring the progesterone levels in the blood however, there is no a proven method or internationally accepted academic study that show when or which day the embryo transfer should be performed.
ERA, the only method in the literature for the determination of the day of embryo transfer
The only method currently known that helps to determine the day of personal embryo transfer in the literature is ERA (Endometrial Receptivity Analysis) test. The most appropriate time for the implantation of the embryo is tried to be identified with this test by analysing gene activities in the tissue obtained from the uterus at an appropriate time by the doctor following-up the treatment. The efficacy of the ERA Test is also proven with clinical studies. Far more effective results than all known approaches so far can be achieved by treatments carried out in accordance with the day of the personal embryo transfer determined by performing ERA test in the couples, in which pregnancy cannot be achieved although good quality embryos observed and no known uterine problem.