Progesterone is one of the key hormones in pregnancy. It is produced by the ovary during the luteal phase of the menstrual cycle, just right after ovulation has taken place. Its function is to promote the necessary changes in the endometrium to make it receptive for the embryo, especially during its arrival and implantation.
Progesterone and pregnancy:
Pregnancy needs progesterone for its correct development. In addition to the endometrial changes, progesterone also acts on the uterine musculature by relaxing it, facilitating the growth of the pregnancy inside the uterus.
On the other hand, during pregnancy there must also be a suppression of immune function at the uterine level, in order to prevent the body itself from reacting against the pregnancy. Otherwise, the mother's antibodies would attack the pregnancy, thereby preventing the sitting from taking place normally. It has been shown that progesterone also participates in this immunoregulation at the uterine level, easing the correct development of the embryo.
During the early stages of pregnancy, progesterone secretion depends directly on the corpus luteum, which remains in the ovary after ovulation. As the pregnancy progresses, the placenta gradually takes over the production of hormones such as progesterone and becomes totally dependent on it after three months of gestation.
Due to all these reasons, the importance of progesterone in pregnancy is discernible, which is why its administration is necessary in assisted reproduction treatments.
Progesterone and IVF
In treatments such as in artificial insemination and in vitro fertilisation , we recommend its use to support the luteal phase. Particularly when it comes to in vitro fertilisation, due to the negative effect that follicular puncture may have, even though the ovaries function correctly, exogenous progesterone is administered to guarantee the correct levels until the placenta takes over its production.
On the other hand, in treatments such as egg donation , embryo donation or frozen embryo transfer, the administration of progesterone is essential to achieve pregnancy and for it to develop correctly. In these treatments, the aim is for the ovaries not to function so that they do not interfere in the endometrial preparation. Therefore, we will have to administer the necessary progesterone to achieve pregnancy and maintain its development.
In Spain, progesterone preparation is indicated for vaginal, oral or subcutaneous administration. Initially, we recommend the vaginal route as its effect is mainly at the uterine level, avoiding its systemic effects, such as dizziness. Subcutaneous progesterone is an alternative for patients with allergies or suspected malabsorption via the vaginal route.
