According to statistics from the Domestic Reproductive Medicine Center, the incidence of early abortion during the test-tube cycle is about 15%-20%. For many families, after surviving the hormone response during expulsion and the recovery period after egg retrieval, but experiencing pregnancy termination after successful transplantation, they not only have to face physical trauma, but also easily fall into the confusion of "where the problem lies." In fact, in vitro abortion is not caused by a single factor, but is the result of the combined effect of multi-dimensional risks such as embryo quality, maternal conditions, and paternal influence. This article will combine clinical cases with the latest research data to break down those key triggers that are easily ignored and provide more targeted reference for subsequent pregnancy preparations.
Whether the embryo can be implanted and developed normally depends on its own quality.
,.Clinical data shows that about 60% of early in vitro abortions are directly related to embryonic abnormalities, mainly reflected in two aspects.
Thefirst is chromosomal abnormalities.If chromosomes are not separated during meiosis of an egg, or chromosome fragments are misaligned during sperm formation, the fertilized egg will cause abnormal chromosomes, such as common types such as trisomy 21 and trisomy 18. Even if such embryos are temporarily implanted, they will not be able to support subsequent development, and most of them will be naturally eliminated at 6-8 weeks of pregnancy. Especially for women over the age of 35, the rate of egg chromosome abnormalities has increased from 1%-2% in their youth to more than 5%, and exceeded 10% after the age of 40, directly increasing the risk of abortion; after the age of 40, the probability of sperm chromosome aberrations will also increase significantly.
The second issue is insufficient developmental potential.Test tube embryos need to be cultured in the laboratory for 3-5 days. If the egg granulosa cell vitality is poor and the sperm forward movement rate is less than 32%(WHO standard), even if a fertilized egg is formed, it may not be able to develop to the blastocyst stage, or it is difficult to establish a stable connection with the endometrium after transplantation, which ultimately leads to abortion. Data from a reproductive center shows that the post-transfer abortion rate of embryos formed from low-vitality eggs is 30% higher than that of high-quality egg embryos.
If the embryo is the "foundation", the maternal environment is the "soil" for the embryo to grow, and abnormalities such as uterine structure, endocrine, and immune status will directly affect the pregnancy outcome.
Uterusstructural abnormalities are common hidden dangers.
Abnormal uterine structures are a common risk factor.In clinical practice, about 12% of patients with repeated abortion have intrauterine adhesions. Insufficient blood supply to the endometrium caused by adhesions will stop the development of the embryo due to "nutritional deficiency"; if the diameter of submucosal uterine fibroids exceeds 1cm, they will directly occupy the embryo. In the implantation space, the risk of abortion is 2.5 times higher than that of those without fibroids; in patients with mediastinal uterus, due to abnormal uterine cavity shape, embryos are easy to implant in the mediastinal area with poor blood supply, and the early abortion rate can reach 40%.
Endocrine imbalance can disrupt the normal rhythm of pregnancy.Insufficient corpus luteal function is an important cause of early abortion. About 35% of patients with early abortion have insufficient progesterone secretion, which leads to the inability of the endometrium to maintain the "pregnant state" and premature shedding; if TSH (thyroid stimulating hormone) in patients with hypothyroidism is higher than 2.5mIU/L, placental blood supply will be reduced by more than 20%, affecting the nutritional supply of the embryo; Patients with polycystic ovary syndrome will have reduced endometrial receptivity due to insulin resistance. Even if the embryo is implanted, it is easy to cause abortion due to insufficient endometrial nutrition.
“”.In patients with antiphospholipid antibody syndrome, antibodies in the body may cause embolism of small blood vessels in the placenta and cut off the oxygen and nutrient channels of the embryo. The repeated abortion rate in such patients can reach more than 50%; if the condition of patients with systemic lupus erythematosus is not well controlled, immune cells will attack the embryonic tissue; there are also some women who lack blocking antibodies and are unable to recognize the paternal gene in the embryo and attack it as a "foreign body", resulting in the termination of pregnancy.
.During TORCH screening, if Toxoplasma gondii IgM is positive, the risk of embryo infection reaches 30%, which may cause abnormalities in the development of the central nervous system; Mycoplasma and chlamydia infections can cause endometritis, increase inflammatory factors in the lining, and reduce the success rate of embryo implantation; If patients with bacterial vaginitis are not treated in advance, the risk of abortion will increase by 1.8 times.
Many people think that abortion is only related to women, but in fact, the influence of fathers cannot beunderestimated
The first is that the genetic material of the sperm is abnormal.
The first issue is abnormal genetic material in sperm.If a man has a balanced chromosome translocation, the probability of chromosomal abnormalities in the fertilized egg after the sperm and egg are combined can reach 50%. Most of these embryos will abort or develop into abnormal fetuses; a study has shown that men whose sperm DNA fragmentation rate exceeds 30%, The risk of in vitro abortion is 2.3 times higher than that of the normal population, and long-term smoking and exposure to high temperature environments (such as frequent saunas) will increase the sperm DNA fragmentation rate.
The second issue is related to the hidden problems associated with sperm quality.Even if the sperm concentration and vitality are up to standard during routine semen examination, if the sperm acrosin activity is insufficient, it will affect the division speed after the fertilized egg is formed; there is also a high sperm deformity rate (more than 96%), which may lead to a decrease in the development potential of the embryo., indirectly increasing the risk of abortion.
In addition to physiological factors, inappropriate links in the external environment and treatment procedures may also inducemiscarriage
The impact of environmentally harmful substances needs to be vigilant.
It is necessary to be vigilant against the effects of harmful substances in the environment.Long-term exposure to formaldehyde (such as a new house without ventilation after decoration) can cause chromosome aberrations in germ cells, while benzene compounds can reduce egg quality; in men exposed to high temperatures above 37 ° C for a long time (such as chefs and metallurgical industry practitioners), sperm vitality will decrease by 15%-20%, and DNA integrity will also be impaired; when women are exposed to high doses of ionizing radiation during pregnancy (such as unprotected CT examinations), the risk of mutation in embryonic cells will increase significantly.
It is necessary to scientifically avoid the risks associated with treatment.Some patients choose to transfer two embryos, but the risk of abortion in twin pregnancy is 3-4 times that of single pregnancies, and it is easy to cause complications such as gestational hypertension and anemia; if the dose is inappropriate, it may lead to excessive stimulation of the eggs and affect the quality of the eggs. However, under standardized diagnosis and treatment, the incidence of such conditions can be controlled within 5%. Insufficient or excessive progesterone supplementation may also affect the status of the endometrium, which needs to be dynamically adjusted according to blood progesterone levels.
Facing in vitro abortion, blind anxiety is not as good as accurateresponse
The first step is a comprehensive investigation.
The first step is to conduct a comprehensive inspection.Within 3 months after abortion, it is recommended that both couples complete chromosome karyotype analysis. Women undergo hysteroscopy (to check for uterine structural problems), endocrine kits (progesterone, thyroid function, insulin, etc.), and immune indicator screening (anti-phospholipid antibodies, blocking antibodies, etc.). Men need to test sperm DNA fragmentation rate and acrosin activity to clarify the specific triggers.
The second step is targeted intervention.For example, intrauterine adhesions can be treated through hysteroscopic separation. If the endometrial membrane is repaired well after surgery or if the corpus luteal function is insufficient, progesterone gel or injection can be used after transplantation to maintain progesterone levels; for patients with immune abnormalities, doctors may use an anticoagulant regimen of low-molecular-weight heparin combined with aspirin, and the clinical effectiveness rate can reach more than 70%.
The third step is to adjust your lifestyle.Men need to quit smoking and alcohol and avoid high temperatures, while women need to work regularly and control their weight (BMI maintained at 18.5-24). Both parties should avoid exposure to toxic chemicals, and at the same time, they can relieve anxiety through psychological counseling-data from a reproductive center show that patients who receive psychological intervention