What causes a drop in progesterone in early pregnancy?

Women are very careful in the early stages of pregnancy. They pay close attention to their own health. Many women also experience low progesterone levels in the early stages of pregnancy, which makes pregnant women very nervous. It is understood that the cause of low progesterone is likely to be threatened abortion, ectopic pregnancy and other reasons. Pregnant women should check the cause in time, adjust their diet, maintain a healthy lifestyle and protect the fetus through drug treatment.

1. What is progesterone?

Progesterone, or pregnane-4-ene-3,20-dione, is an endogenous steroid and progestogenic sex hormone and the major progestogen in the body. Progesterone, also known as progesterone, abbreviated as "P" in English, is also called progesterone, progesterone, progesterone, progestin, progestin or progesterone. It is a hormone secreted by the corpus luteum in the ovaries in the female body. It mainly regulates female endocrine, involving female menstrual cycle, pregnancy and steroids that affect the embryos of humans and other animals.

Produced by the corpus luteum of the ovary in early pregnancy, progesterone is an important hormone that supports the early growth and development of the fetus. High concentrations of progesterone have a significant calming effect on the enlarged uterus and are also very important for supporting early pregnancy.

After pregnancy, the placenta will secrete HCG (human chorionic gonadotropin). One of the functions of HCG is to stimulate the corpus luteum to secrete progesterone, a steroid hormone secreted by the ovaries. It gradually transitions to placental production in 7 to 9 weeks, also known as luteal placental transfer. At 10 to 11 weeks, the placenta produces a significant increase in progesterone. At this time, the trophoblast cells of the placenta take over the corpus luteum to produce progesterone and maintain pregnancy.

2. What is the role of progesterone?

(1) The role of progesterone in the pregnancy preparation period

The main function of progesterone is to cooperate with estrogen to participate in maintaining the functional activities of the normal menstrual cycle. The main function of progesterone is to make the glands in the endometrium grow, the uterus become congested, and the endometrium thicken in the late menstrual cycle to prepare for the implantation of the fertilized egg. After ovulation, under the action of progesterone secreted by the corpus luteum, the endometrium transforms from the proliferative phase to the secretory phase, making the endometrium receptive to embryo implantation. Decidual cells are transformed from endometrial stromal cells and contain glycogen granules, preparing for the fertilized egg to "move into the uterus".

Secondly, progesterone can induce the decidualization of the endometrial stroma and regulate the expression of various implantation-related factors in an autocrine or paracrine manner. Progesterone is necessary to maintain the decidual reaction.

(2) The role of progesterone during pregnancy

After the fertilized egg is implanted, the placenta is produced. Progesterone reduces the excitability of the pregnant uterus, inhibits its activity, and allows the fetus to grow safely. Working together with estrogen, progesterone can promote the growth of mammary alveoli to prepare for lactation, increase body temperature and relax blood vessels and digestive tract smooth muscles.

(3) The role of progesterone during pregnancy:

A. Immune protection: Progesterone has immune protection and can inhibit immune response. When a woman is in a normal pregnancy, progesterone increases, which prevents the embryo from being rejected by the mother and maintains the pregnancy. When there is a lack of progesterone, the embryo may be rejected by the mother and cause miscarriage.

B. Blastocyst implantation: During ovulation, under the action of progesterone secreted by the corpus luteum, the endometrium transforms from the proliferative phase to the secretory phase, making the endometrium receptive to embryo implantation. Decidual cells are transformed from endometrial stromal cells and contain glycogen granules, which provide nutrition to the blastocyst. Progesterone can induce the decidualization of endometrial stroma and regulate the expression of various implantation-related factors in an autocrine or paracrine manner.

3. Can testing progesterone save the fetus?

People monitor progesterone levels in early pregnancy because they are afraid of miscarriage and worry that pregnancy loss is caused by lack of progesterone. Can progesterone supplementation really prevent and treat miscarriage? What serum progesterone level requires progesterone supplementation? In fact, the cause of spontaneous abortion is very complex. About 50% of them are caused by random errors in the chromosomes of the fetal villi, which is called aneuploidy. Other recognized causes include uterine malformation, antiphospholipid syndrome, endocrine factors, thrombophilia, etc. Some miscarriages are accidental events. If they occur more than twice in a row, it is called recurrent miscarriage.

Among them, it seems that only endocrine factors may involve progesterone deficiency and become the basis for the use of progesterone. Endocrine factors include diabetes, insulin resistance, hypothyroidism, ovulation disorders and other problems.

4. Under what circumstances is it necessary to test progesterone?

Progesterone testing during pregnancy is mainly used to understand the function of the corpus luteum, whether the ovaries have ovulated, and the status of pregnancy.

Most pregnant women do not need progesterone testing. Progesterone testing is necessary if any of the following occurs:

(1) Have a history of spontaneous abortion or recurrent miscarriage;

(2) Patients have been diagnosed with luteal insufficiency by a doctor in the past;

(3) Pregnancy through assisted reproductive technology;

(4) The current pregnancy has symptoms of threatened abortion such as vaginal bleeding and lower abdominal pain;

If the pregnant woman has had normal menstrual cycles in the past, has no history of miscarriage, and does not experience symptoms such as lower body bleeding or abdominal pain during this pregnancy, there is no need to test for progesterone.

5. How to check progesterone

The progesterone test is conducted by drawing venous blood from the pregnant mother. Since the progesterone content is not affected by eating, the progesterone test does not require fasting, and the mother can drink water during the test. Generally, after the examination in the morning, the results can be obtained in the afternoon.

6. Progesterone test instructions

During the entire menstrual cycle of a normal non-pregnant woman, the progesterone level is lowest before ovulation, begins to rise after ovulation, and reaches its highest level during the luteal phase. Before ovulation, the progesterone level in body fluids should be less than 2 ng/mL, and after ovulation it should be greater than 5 ng/mL. If you become pregnant, the progesterone level will initially remain at the level of the luteal phase. After the placenta is formed, the hormones secreted by the placenta will increase the progesterone level in the pregnant woman's body to 100-200 ng/ml, which is dozens to hundreds of times that of a non-pregnant woman.

——Decoding “Low Progesterone”

1. Causes of low progesterone

The reasons for low progesterone include threatened abortion, ectopic pregnancy, premature birth, amenorrhea, infertility, or corpus luteum insufficiency. When the corpus luteum of the ovary is not fully developed, the progesterone level will also decrease. Severe disorders of the adrenal and thyroid glands can also affect ovarian function, causing ovulation disorders and a corresponding decrease in progesterone levels. The body develops insulin resistance, and the progesterone level will also decrease. Unhealthy lifestyles such as chronic stress, high intake of sugar in the diet but lack of adequate nutrition, and lack of exercise. Medication factors can also cause low progesterone levels.

2. Symptoms of low progesterone:

Symptoms include underactive thyroid, fibrocystic breasts, gallbladder disease, hypoglycemia, irregular menstrual cycles, weight gain, vaginal dryness, etc. Some patients may also experience breast tenderness, gallbladder disease, and blood clots during menstruation.

3. "Low progesterone" solution

(1) Identify the cause

Conduct relevant examinations in a timely manner to identify the causative factors. Exclude some endocrine diseases (such as hyperprolactinemia, adrenal dysfunction, thyroid dysfunction) that cause luteal insufficiency and decreased progesterone secretion. It is also necessary to rule out low progesterone levels due to embryonic maldevelopment or ectopic pregnancy.

(2) Diet adjustment

Progesterone can maintain regular menstruation. If low progesterone occurs before pregnancy, it must be treated before having a baby. When the progesterone level is low, you should go to a regular hospital for relevant examinations in time, identify the causative factors, and receive symptomatic treatment.

You can also regulate your progesterone levels through diet. You can consume foods rich in soy isoflavones and natural vitamin E. Soy isoflavones and sufficient vitamin E can help regulate the balance of progesterone, such as soybeans, soy milk, soy products, walnuts, sesame seeds, flax seeds, etc. Eat more fresh fruits and vegetables rich in vitamin C. Eating some apples, peaches, grapefruits, strawberries, kiwis, pears, etc. that are rich in pectin and dietary fiber will not cause large fluctuations in blood sugar. From the perspective of traditional Chinese medicine, low progesterone indicates a weak constitution and deficiency of qi and blood. You can supplement with some foods that nourish qi and blood, such as angelica chicken soup, black bean chicken feet, ginseng chicken soup, and astragalus pork tripe soup.

4. Maintain a healthy lifestyle

Women with low progesterone, especially pregnant mothers, should have a calm mind, eat regularly, have a balanced diet, exercise scientifically, ensure good sleep and mood, and maintain a healthy weight.

5. Medication

One is to directly inject corpus luteum copper, and the other is to take progesterone tablets orally. The former is more affordable, and the latter is more convenient, but both methods are effective. However, these two methods must be carried out under the guidance of a doctor, especially progesterone tablets must not be taken privately.

Pregnant women should test the progesterone concentration in their blood before taking the medicine. If threatened abortion occurs within 3 months of pregnancy, it is mostly related to luteal insufficiency. The use of progesterone is effective. After 3 months of pregnancy, the placenta can secrete and no longer depends on the secretion of the ovarian corpus luteum. Therefore, abortion at this time is mostly caused by other reasons, and the use of progesterone will have little effect.

6. Misconceptions about progesterone supplementation

(1) Let the data speak for itself

There is recent data to support whether progesterone should be used during pregnancy.

Dr. Martinez de Tejada B, Department of Obstetrics and Gynecology, University of Geneva Medical School, conducted a large trial to study this topic.

The trial was conducted in Switzerland (9 centers) and Argentina (20 centers) and evaluated a total of 379 women (193 women taking progesterone and 186 women taking placebo).

The study found that 42.5% of women in the progesterone group experienced premature birth, while 35.5% of women in the placebo group experienced premature birth.

Conclusions: When therapeutic preterm birth was excluded, the risk of spontaneous preterm birth was higher in the progesterone group. In Switzerland, progesterone use increased the risk of spontaneous delivery within 14 days and preterm birth before 37 weeks of gestation compared with placebo. Therefore, based on the existing literature, progesterone should not be used as a method to maintain pregnancy in women with preterm labor.

(2) What are the dangers of blindly supplementing hormones?

The causes of spontaneous abortion include chromosomal abnormalities, placental abnormalities, uterine abnormalities, sex hormone imbalance, infection, chronic diseases, etc.

According to the eighth edition of the textbook of obstetrics and gynecology, chromosomal abnormalities of the embryo or fetus are the most common cause of early miscarriage, accounting for about 50%-60%. After excluding other reasons, only a small number of patients suffer miscarriage due to hormone deficiency.

The use of exogenous hormones to promote the growth and development of the embryo should be done when the pregnant woman's own hormone secretion is insufficient. If there is no hormone deficiency, supplementing too much hormone will only cause adverse effects on the fetus and pregnant women.

A. Excessive progesterone can cause many male fetuses to have renal pelvic dilatation, even hydronephrosis, genital abnormalities, and female fetuses to have genital organ tumors after puberty;

Excess HCG can also affect the results of Down syndrome screening during pregnancy (turning a true high risk into a false low risk).

B. Excessive progesterone can also affect the appetite and water metabolism of pregnant women.

In some cases, abnormal embryos (embryos with Down syndrome or other chromosomal abnormalities) can also lead to insufficient hormone secretion. If large doses of exogenous hormones are used to preserve the pregnancy, the result is that the embryo that should have been aborted survives, and the outcome can be imagined.