Hormones work in concert throughout your pregnancy, but each has its specific function. The explanations of Dr. François Devianne, gynecologist-obstetrician at the Orsay hospital.
Hormones, what is it?
- Without the hormones, we would be nothing. It is, indeed, thanks to them that spermatozoa and ovules are released and meet ... their power is immense, even if their presence in our blood is tiny.
- Hormones are substances secreted mainly by the endocrine glands: the pituitary (located under the temple at the level of the eye), particularly active in the secretions of hormones accompanying the menstrual cycle, the thyroid (located in the cruex of the neck) and his companions parathyroid, adrenal (located on each of the kidneys and ovaries).
- They are also made by different cellular formations scattered throughout the body, such as the kidneys, and the placenta in pregnant women.
HCG: the hormone that reveals pregnancy
- Each month, at the time of ovulation, the oocyte borrows the fallopian tube to meet a sperm. If he is at the rendezvous, it is fertilization. The egg then continues on its way and is implanted eight days later in the uterus for implantation, which corresponds to about the 20th day of the cycle. This implantation triggers the production of a hormone, hCG (chorionic gonadotropin hormone), by the cells of the future placenta, the trophoblast. It is his presence that is sought during the pregnancy testfor it is present only in the urine or blood of pregnant women.
- The beta hCG hormone is detectable as early as the 9th day after ovulation and fertilization, and its secretion doubles every two to three days. Rejoice: it is a sign of vitality of your pregnancy. This release of hormone is often associated with the occurrence of nausea. The hCG level peaks at week 8, and falls between 14 and 18 weeks of amenorrhea. A major relief for many pregnant women, because a lower production of hCG is equivalent to the decrease, or even the disappearance of nausea.
- To know : the secretion of hCG is variable from one pregnancy to another and is increased with twins. In the context of trisomy 21 screening, this hormone is also a marker of choice, alongside estriol and alpha fetoprotein.
The yellow body: a provider of hormones for your baby to settle
- At the level of the ovary, the follicle emptied of its egg fills with cells of yellow color: it's the yellow body. It will persist thanks to the increasing rate of hCG and secrete progesterone and estrogen for about 8 weeks, until the placenta, which regulates mother-child exchanges, takes over. The yellow body is one of the great protectors of the egg the first days.
Progesterone, an essential hormone for your pregnancy
Irresistible desire to sleep, calm, serenity? Bless the progesterone.
- Progesterone helps implant the embryo, supports and thickens the wall of the uterus (endometrium). Produced by the corpus luteum at the beginning of pregnancy, it is entirely emitted by the only placenta from the 12th week. During these nine months, its dosage makes it possible to test the good placental activity. If you have difficulty getting pregnant, your doctor may prescribe progesterone adjunctive therapy during the second phase of the cycle. In the same way, this hormone is proposed in case of threat of premature delivery.
- Good to know: progesterone increases body temperature by a few tenths of a degree: this explains the temperature shift after ovulation.
Estriol, for a uterus at the top
- The placenta secretes increasing amounts of estrogen (mainly estriol) until the end of pregnancy. This contribution promotes multiplication of endometrial cells and growth of the uterus. Judge instead: 6 cm long and about 50 g, "this baby bag" reaches a thousand times its original volume and weighs more than 1 kg at term.