In the early stages of pregnancy, the progesterone of maternal blood is mainly derived from the ovarian luteum, and after 8 weeks of pregnancy, it is mainly derived from the placenta, and at this time, the function of placental synthesis of progesterone has completely replaced the function of ovarian luteal synthesis of progesterone. Unlike other primates, levels of progestogens during pregnancy in humans gradually increase with the number of weeks of pregnancy until the third trimester (see figure below).
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How are progesterones synthesized?
After ovulation, a large number of new blood vessels grow into the walls of collapsed follicles and turn into a corpus luteum. LH promotes the secretion of large amounts of progesterone and estrogen by the cells of the luteal body. The endometrium is affected by both estrogen and progesterone into the secretory phase in preparation for conception. If not conceived, by the negative feedback of estrogen and progesterone, FSH and LH secretion is reduced, luteal atrophy degenerates, menstruation occurs; if conceived, about 6 days after fertilization, blastocyst trophoblasts secrete hCG to maintain the luteal function of the ovaries, and transform into gestational luteum, continuing to secrete progesterone and estrogen.
At 8 weeks of gestation, the placenta forms and placental syncytial trophoblasts begin to secrete progesterone until week 10, when the placenta becomes the main site for synthesizing progesterone and estrogen.
The regulation of progesterone synthesis can be affected by a variety of hormones, such as insulin, growth hormone, prolactin, FSH, prostaglandins, etc., but the most important is LH and hCG.
What are the effects of progesterone?
1. The receptors of progesterone are present in the epithelial cells, uterine stromal cells and myometrium of the uterine lining and glands, etc. Estrogen promotes the expression of progesterone receptors, and progesterone is negative feedback regulation.
2. Progestogen can maintain the quiet state of uterine smooth muscle during pregnancy and prevent the contraction of uterine smooth muscle;
3. Progesterone can stimulate the development of breast acinar vesicles and the proliferation of breast lobules, in preparation for lactation after childbirth;
4. Progesterone can act to regulate the hypothalamus thermoregulatory center to raise the basal body temperature;
5. Progesterone can show dynamic antagonism of estrogen during pregnancy, inhibit endometrial hyperplasia through antagonism of estrogen in the first trimester of pregnancy, weaken the antagonism in the third trimester, and increase estrogen levels, which is conducive to initiating childbirth.
What is the secretion of progesterone?
Progesterone releases progesterone intermittently throughout the day, and each person's progesterone receptor function is different, so the transient progesterone value does not fully reflect the total amount of progesterone in the blood, is not of great significance, and cannot predict pregnancy outcome.
Under physiological conditions, it is sufficient for humans to maintain a normal pregnancy within 12 weeks of pregnancy with a serum progesterone level of 20-30 ng/ml.
What is the significance of testing for progesterone?
1. It is recommended to measure hCG in early pregnancy to assess pregnancy status, hCG > 25ug/L can be diagnosed as clinical pregnancy, rather than the determination of progesterone.
2. For pregnant women, the level of progesterone does not effectively indicate the function of the luteal body. However, in view of the nervousness and worry in women in early pregnancy, and the combination of threatened miscarriage and recurrent miscarriage, prophylogen supplementation "fetal protection therapy" can be prevented, and the treatment plan can be adjusted according to the results of hCG and ultrasound.
3, but low progesterone is not the cause of miscarriage, inevitable abortion of patients with progesterone value reduction is the result of abnormal embryo quality, through the supplement of progesterone is also useless, at this time, the reduction of progesterone is the consequence of embryo cessation.
4. For non-pregnant women, we can determine whether they have ovulated by measuring progesterone.
When is luteal support required?
According to the "Luteal Support and Progestin Supplementation Consensus", indications for luteal support also include:
1. Fertility treatment such as in vitro fertilization/intravellicular sperm injection-embryo transfer (IVF/ICSI-ET) is applied to the superovulation induction program, and there is a certain degree of endogenous luteal deficiency after ET
2. When freeze-thaw embryo transfer (FET) is carried out after ovulation in the natural cycle, some women may have their own luteal insufficiency;
3. When the FET is implemented in the ovulation induction cycle, there is a potential endogenous luteal deficiency;
4. Estrogen and progestin drug replacement cycle (artificial cycle) FET, completely using exogenous estrogen and progesterone drugs to replace luteal function;
5. Previous history of recurrent miscarriage;
6. Threatened preterm birth.
contraindication
Patients with suspected or present arteriologic and venous thrombosis, patients with a history of phlebitis and stroke should be used with caution;
Malignant tumors of the breast or hormone-dependent tumors of the reproductive system, patients with clear contraindications to estrogen therapy;
People with progesterone allergies.
When do I need progesterone?
1. Taking women with regular menstruation and a menstrual cycle of 28 days as an example, progesterone is detected on the 21st-23rd day of menstruation to determine whether there is ovulation and whether ovulation is normal, which can be used as a basic examination for infertility patients;
2. Confirm whether ovulation occurs after the application of ovulation induction drugs;
3. Abnormal uterine bleeding occurs in sexually active and unpregnant women;
4. When abdominal pain, symptoms of threatened miscarriage, etc., the examination indicates suspicious ectopic pregnancy;
5. High-risk pregnant women monitor the placenta and fetal survival;
6. It is used to exclude certain diseases, such as ovarian luteal cysts, moles, congenital adrenal hyperplasia, chorioepithelial cell lesions, lipid ovarian tumors, etc.
What is the normal progesterone value during pregnancy?
The average progesterone content in women during pregnancy is 25 ng/ml (80.3 nmol/L), when the progesterone value of pregnant women is ≥ the range of 25 ng/ml is normal, when the progesterone content is between 15 and 25 ng/ml, it indicates that there may be insufficient luteal function, and when the progesterone content is ≤ 15 ng/ml and there is no fetal heartbeat under ultrasound, adverse pregnancies may occur, and threatened miscarriage or miscarriage is inevitable.
How to Raise Progesterone?
1. If there is a threatened miscarriage, oral progesterone preparations, such as didraprogesterone and progesterone, should be taken orally;
2, diet can eat more soybeans, strawberries, grapefruit, kiwifruit, pectin foods and rich in dietary fiber can help supplement progesterone and vitamin E;
3. Reduce fatigue and rest fully, and also help the recovery of hormones in the body.
Progesterone is not standard for testing in early pregnancy, and abnormalities such as abdominal pain and vaginal bleeding do not require repeated progesterone checks, and progesterone levels do not reflect pregnancy outcomes. Of course, prophylactic progesterone is necessary in patients with a history of poor pregnancy in assisted reproductive technologies.