Recurrent miscarriage refers to 2 or more consecutive spontaneous miscarriages, or what we usually call habitual miscarriage. It is called “slippery fetus” in Chinese medicine.
The etiology of recurrent spontaneous abortion is complex and has been a hot topic of research in the past 20 years. It is generally believed that for early spontaneous abortions occurring before 12 weeks of pregnancy, the common causes are chromosomal abnormalities, luteal insufficiency and immune factors; while for late spontaneous abortions occurring between 12 and 28 weeks of pregnancy, the common causes are uterine malformations, relaxation of the endocervix and systemic diseases. Nearly half of the recurrent spontaneous abortions have an unidentified cause at present.
I. Genetic factors: chromosomal abnormalities are a common cause of recurrent spontaneous abortion. In early pregnancy spontaneous abortion, the incidence of karyotype abnormalities is as high as 50-60%. There is no effective treatment yet, only prenatal genetic counseling and diagnosis can be performed. Another situation is when both spouses are chromosomally normal, but chromosomal abnormalities occur during gamete formation and embryo development.
For example, women older than 35 years old with aging eggs are prone to chromosomal non-separation, resulting in chromosomal abnormalities. Semen abnormalities such as large-headed malformed sperm are mostly diploid and form polyploid embryos after fertilization leading to miscarriage. Adverse environment such as toxic chemicals, radiation, high temperature, etc. can also cause chromosomal abnormalities in embryos.
Second, endocrine factors: about 20%-25%, the common cause is luteal insufficiency.
Luteal insufficiency: the ovarian corpus luteum secretes progesterone. Insufficient progesterone can lead to endometrial dysplasia, which prevents implantation of pregnant eggs and early embryo development. Before 8 weeks of gestation, the main source of progesterone is the corpus luteum of pregnancy. After the 8th week of gestation, the placental trophoblasts gradually replace the corpus luteum as the main source of progesterone. For pregnant women with luteal insufficiency in early pregnancy, exogenous progesterone such as progesterone and human chorionic gonadotropin can be given as a substitute until the placenta is formed.
2, hyperprolactinemia: lactogen inhibits the function of the corpus luteum, making the luteal phase shorter and progesterone insufficient; at the same time, it can also affect the local normal level of prolactin in the uterus, affecting the development of the embryo and causing miscarriage. Patients who are diagnosed with hyperprolactinemia should be treated with bromocriptine under the guidance of a doctor.
3. Endometriosis: Patients with endometriosis have a high rate of spontaneous abortion, about 30%, with complex causes and mechanisms.
4, polycystic ovary syndrome: recurrent spontaneous abortions occur in about 40% of patients with polycystic ovary syndrome, mainly due to concomitant hyperprolactinemia, luteal insufficiency, low estrogen levels, poor egg quality, and endometrial abnormalities.
5. Thyroid dysfunction and diabetes mellitus: this type of disease can also lead to miscarriage. Once you have a history of multiple miscarriages, you should undergo a systematic examination and become pregnant after the relevant diseases are ruled out.
6.Anatomical factors
Anatomical factors include congenital abnormal uterine development, such as infantile uterus, unicornuate uterus, bicornuate uterus, longitudinal/transverse uterine septum, uterine cavity adhesions, submucosal fibroids, polyps, cervical insufficiency, etc. Causes of miscarriage can occur in early pregnancy (insufficient blood flow to the site of implantation) or in mid-pregnancy (structural defects of the uterus, abnormal tolerability, insufficient blood supply). For most anatomical factors causing recurrent spontaneous abortions, targeted surgery can be performed. Especially for those with simple cervical insufficiency, the timely choice of endocervical ligation is very effective.
7.Infection factors
A variety of pathogenic infections in the female reproductive tract can lead to miscarriage, including mycoplasma, chlamydia, toxoplasma, gonococcus, listeria, herpes simplex virus, rubella virus, cytomegalovirus and protozoa. Screening for these pathogens is basically included in the routine TORCH five tests. Most of these infections, which have no obvious symptoms, should be examined before pregnancy to prevent accidents.
8. Immunological factors
During normal pregnancy, the embryo is a homozygous natural graft with 1/2 of the father’s genetic material. In order to ensure that the embryo is not rejected by the mother, many changes occur in the maternal immune function, and when there is an abnormality in one of the immune factors, it leads to multiple spontaneous abortions. Commonly detectable immune abnormalities include maternal closed antibody deficiency, certain autoantibodies in the serum, such as anticardiolipin antibodies, anticore antibodies, antithyroid antibodies. Blood group incompatibility, positive anti-sperm antibodies, etc. Lack of blocking antibodies is the main cause of habitual abortion.
9.Systemic diseases
Serious systemic diseases, such as cardiovascular diseases, kidney diseases, blood diseases, acute infectious diseases, certain sexually transmitted diseases and autoimmune diseases can lead to miscarriage.
10.Male factor
In the past, this factor was often overlooked, but in fact, male factors such as semen factor, semen non-liquefaction, high sperm malformation rate, low sperm vitality, and sperm agglutination can cause miscarriage. Once the occurrence of this type of disease, should do this aspect of the examination, do not put the blame on the wife.
11.The cause is unknown
Although medicine is more advanced now, there are still 40% of multiple spontaneous abortions for which the cause cannot be identified. It is believed that with the progress of medical technology, it can be gradually recognized.
The psychological burden of recurrent spontaneous miscarriage to pregnant women and their families is heavy. In fact, one should not worry too much. Because multiple spontaneous abortions are not incurable and normal delivery is possible even without any treatment. After one spontaneous abortion, the chance of spontaneous abortion in another pregnancy is 24%, 26% after 2 times and 32% after 3 times. Even after 4 consecutive spontaneous abortions, the chance of a normal delivery in a second pregnancy is 55%. Patients with recurrent spontaneous abortions should cooperate with their doctors and actively search for the cause of the abortion. Under the guidance of the doctor, the pregnancy will be safer and the baby will be healthy and lovely.