Is it normal to have no fetal heartbeat or embryo at 6 weeks?

Don't be too anxious if there is no fetal heartbeat or fetal bud at 6 weeks. Some fetuses are slower in development and this may happen. You still need to observe the actual condition of the fetus in the abdomen. If there has been no fetal heartbeat for a long time, you need to pay attention to it. It may be caused by the fetus being infected with an acute infectious disease. In severe cases, the fetus may directly die or be poisoned, and you need to deal with it as soon as possible.

1. Embryonic (or fetal) factors

1. Abnormal embryonic development is the most common cause of early miscarriage, and miscarriage caused by chromosomal abnormalities accounts for about 50-60%.

2. Placental abnormalities due to trophoblastic dysplasia, degeneration of placental villi, or low attachment of the placenta can cause fetal-placental circulation disorders and lead to miscarriage.

2. Maternal factors

1. Acute infectious diseases can cause fetal death due to pathogens or toxins invading through the placenta, or cause uterine contractions and miscarriage due to high fever or poisoning;

2. Severe anemia or heart failure, resulting in fetal hypoxia and death;

3. Endocrine disorders, such as corpus luteum insufficiency, lead to decidua dysplasia and affect the development of fertilized eggs;

4. Uterine hypoplasia, uterine fibroids or malformations can also hinder embryonic development;

5. Sometimes, the relaxation of the internal cervix can cause the inability to withstand the increased pressure of the fetal sac, leading to late miscarriage;

6. Strong mental stimulation, trauma or sexual intercourse can also cause miscarriage, but the inducing factors are often mainly caused by defects in the embryo itself.

(III) External factors

Toxic substances that can cause miscarriage include cadmium, lead, organic mercury, DDT and other radioactive substances. These toxic substances may act directly on the fetal somatic cells or may affect the fetus through the placenta and cause miscarriage.

4. Immune factors

After the mother becomes pregnant, the immune system of both mother and child is not compatible, which causes the mother to reject the fetus and lead to miscarriage. The relevant immune factors that have been discovered include the spouse's tissue compatibility antigens, fetal antigens, blood type antigens, imbalance in maternal cellular immune regulation, maternal blocking antibodies during pregnancy, and lack of maternal cytotoxic antibodies against paternal lymphocytes.

5. Blood type incompatibility between mother and child

Incompatibility of blood types between mother and child often causes late miscarriage, such as ABO blood type and Rh blood type incompatibility.