Patient's question:
Dear friends: I worked hard for 8 months and underwent various tests, and finally confirmed pregnancy on January 30, 2007 (my last menstrual period was on December 20). The doctor recommended that I come to the hospital again for a B between the 50th and 60th day. On February 16, I went to the hospital again for a B, and the B showed a fetal pole but no fetal heartbeat. The doctor said it was too early. It should be more than 50 days, probably around 40 days. So I went home relieved. On the night of March 15, I experienced spotting, and the B still showed no fetal heartbeat. The doctor said it was no longer necessary to keep it. The next morning, I had a D&C procedure. At 3:30 AM, there was a significant amount of blood and tissue flow, and finally, the gestational sac was expelled.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, villous degeneration, or low placental attachment, can disrupt fetal-placental circulation, leading to miscarriage.
(2) Maternal factors:
1. Acute infections can 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 may cause fetal hypoxia and death.
3. Endocrine disorders, such as luteal insufficiency, can result in poor decidual development, impairing embryo growth.
4. Uterine malformation, fibroids, or 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, but these are often contributing factors, with the primary cause usually 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: Maternal rejection of the fetus due to immune incompatibility between the mother and fetus may result in miscarriage. Identified immunological factors include paternal tissue antigens, fetal antigens, blood group antigens, maternal cellular immune regulatory imbalance, lack of maternal during pregnancy, and insufficient maternal cytotoxic antibodies against paternal lymphocytes.
(5) Maternal-fetal blood group incompatibility: Blood group incompatibility between the mother and fetus often causes late miscarriage, such as in cases of ABO or Rh blood group incompatibility.
It is recommended to check endocrine levels and anti-embryonic antibodies using electrochemical luminescence on days 3–5 of the menstrual cycle, perform a vaginal examination on days 3–5 after menstruation, dynamic digital hysterosalpingography, and vaginal four-dimensional color Doppler ultrasound.