Patient's question:
At 40 days of pregnancy, I went to the hospital for a check-up. The doctor said everything was normal, but why did this happen by the time I was two months pregnant? I'm very sad. This has happened to me twice. Is it related to my work environment? I work in a business that involves chemicals and toxic substances. Is this the reason, or is it due to chromosomal issues? Please help, experts.Doctor's answer:
The causes of miscarriage include:(1) Embryonic (or fetal) factors:
1. Abnormal embryonic development is the most common cause of early miscarriage, with chromosomal abnormalities accounting for approximately 50–60% of cases.
2. Placental abnormalities, such as incomplete trophoblast development, degeneration of placental villi, or a low-lying placenta, can disrupt fetal-placental circulation, leading to miscarriage.
(2) Maternal factors:
1. Acute infectious diseases may cause fetal death due to pathogens or toxins invading the placenta, or lead to miscarriage due to high fever or poisoning-induced contractions.
2. Severe anemia or heart failure can cause fetal hypoxia and death.
3. Endocrine disorders, such as luteal insufficiency, can result in poor decidual development, impairing embryo growth.
4. Uterine malformation, uterine fibroids, or congenital uterine abnormalities can also hinder embryonic development.
5. Sometimes, cervical incompetence (relaxation of the internal os) may fail to withstand the pressure of the growing fetal sac, leading to late miscarriage.
6. Severe emotional stress, trauma, or sexual intercourse may also cause miscarriage, though these are often contributing factors, with the primary cause typically being embryonic defects.
(3) External factors: Toxic substances that can cause miscarriage include cadmium, lead, organic mercury, DDT, and other radioactive materials. These toxins may directly affect fetal somatic cells or indirectly influence the fetus through the placenta, leading to miscarriage.
(4) Immunological factors: Immune incompatibility between the mother and fetus may lead to fetal rejection and miscarriage. Identified immunological factors include:
- Spousal histocompatibility antigens
- Fetal antigens
- Blood group antigens
- Maternal cellular immune regulation imbalance
- Maternal (blocking antibodies) deficiency during pregnancy
- Maternal cytotoxic antibodies to paternal lymphocytes deficiency
(5) Maternal-fetal blood type incompatibility: Blood type incompatibility between the mother and fetus often results in late miscarriage, such as in cases of ABO or Rh incompatibility.
Recommended tests:
- Check endocrine levels and anti-embryonic antibodies using electrochemical luminescence on days 3–5 of the menstrual cycle.
- Perform colposcopy, dynamic digital hysterosalpingography, and 4D vaginal ultrasound on days 3–5 after menstruation has ended.