Embryonic development disorder

Introduction The whole process of fetal growth and development in the uterus is about 38 weeks, which is a very complex and highly coordinated physiological process. This prenatal development is called embryonic development. Embryonic development can be divided into three stages: pre-embryo, embryo, and fetal. The early development of the embryo is a relatively important period. The various organs and systems of the human body are basically formed during this period, and embryonic developmental disorders also occur at this stage. This leads to abnormal development of the embryo.

Cause

Embryonic development is mainly determined by the genetic makeup of the embryo and its procedural expression. It has great stability, but it also has certain reversibility. During embryonic development, changes in genetic material or environmental factors can cause abnormal embryo development, leading to miscarriage or birth defects.

1. Genetic factors: Changes in genetic material are important factors leading to abnormal embryonic development, manifested as genetic mutations and chromosomal congenital malformations.

2. The influence of various factors in the environment on embryonic development: Although the embryo can be well protected in intrauterine development, some microorganisms can still directly invade the embryo through the placental barrier, or cause disturbance of maternal physiological metabolism by acting on the mother. To affect the normal development of the embryo, leading to obstacles in the development of various organs, resulting in embryo malformations, mainly manifested as biological factors, chemical factors and teratogenic drugs.

3. Biological factors: The biological factors that have been confirmed to have teratogenic effects on human embryos are: cytomegalovirus, herpes virus, pathogen, herpes simplex virus, syphilis, toxoplasma, and the like. The cytomegalovirus (CMV) species are highly specific, ie human CMV only infects humans. CMV can invade the fetus through the placenta, causing intrauterine infection. The incidence rate is 0.5% to 2.5%, of which 5% to 10% cause clinical symptoms, manifested as jaundice, hepatosplenomegaly, thrombocytopenic purpura, hemolytic anemia and varying degrees of nervous system damage, including cerebellar malformation, mental retardation , deafness, optic atrophy, etc., can seriously lead to miscarriage or stillbirth. The rubella virus belongs to the family of togaviridae. After infection, it can cause congenital malformation of the fetus through vertical transmission. The mitosis and chromosome structure of fetal cells can be changed after infection. Often lead to congenital heart disease, deafness, blindness, mental retardation. Pathogens can infect the fetus through the placenta, leading to premature birth, intrauterine infection of the fetus can be seen with microcephaly, small eyeballs, retinal choroiditis, developmental delay, mental retardation, can seriously lead to stillbirth. Toxoplasma gondii causes fetal disease, which is characterized by latent infections, which can also lead to miscarriage and stillbirth, or hydrocephalus, cerebellar malformation and mental retardation.

4. Chemical factors: Due to the increasingly serious environmental pollution, industrial three wastes, pesticides, food additives and preservatives all contain teratogenic factors. Common heavy metals such as lead and mercury, and phosphorus (chlorine) pesticides and benzene compounds are likely to cause fetal nervous system malformation and death.

5. The teratogenic effects of drugs on the fetus depend on the nature of the drug, the dose, the duration of the episode, and the stage in which the embryo is developed, as well as the sensitivity of the fetal genetic individual to the drug. Large doses of antibiotics, antiviral drugs, antiepileptic drugs, anticancer drugs, etc., have all reported fatal fetuses and deformities.

an examination

Related inspection

Alkaline embryonic protein gynecological ultrasound examination

Embryos are examined and diagnosed by ultrasound or other means.

About a week after fertilization, the blastocyst is implanted into the thickened intrauterine strand, which is called pregnancy. The blastocyst grows up through cell division and cell differentiation and is divided into two parts. Part of it is that the embryo itself will develop into a fetus in the future; the other part will evolve into the outer membrane of the embryo, the most important being the amnion, placenta and umbilical cord, and the fetus exchanges material through the placenta and the mother.

In the first two months, the embryo continues to divide and differentiate cells, produce various cells, and form various tissues and organs. This is a period of development and sensitivity, and it has poor resistance and adaptability to various external stimuli. To pay great attention to safety, including pregnant women taking drugs, receiving radiation or exposure to other harmful factors, will affect the normal development of the fetus; by the end of the third month, the various organ systems have been basically completed, known as the fetus.

In the future, it will mainly increase and a few structural changes, when the resistance is enhanced, but if you do not pay attention, abortion can still occur; after the fifth month, it is safer. Due to the rapid growth of the fetus, the mother's burden is increasing; generally, about 280 days, that is, a little more than nine months (often said "October pregnancy" is actually measured by the lunar calendar) will occur naturally.

Differential diagnosis

Slow embryonic development: Intrauterine growth retardation refers to two standard deviations of fetal weight below the normal average body weight during pregnancy. Generally divided into three categories: endogenous symmetry fetal intrauterine growth retardation, external cause of heterogeneous fetal intrauterine growth retardation, external factor symmetry fetal intrauterine growth retardation.

Embryo cessation: Fetal cessation refers to the developmental stoppage of an embryo in early pregnancy for some reason. B-ultrasound examination showed fetal buds in the gestational sac or fetal form irregularities, no fetal heartbeat, or manifested as gestational sac. Clinically, it belongs to the category of abortion or stillbirth. It used to be called expired abortion or missed abortion. There are many reasons for the embryo to stop developing.

Insufficient blood supply to the embryo: uterine fibroids can make the muscle wall or endometrial venous congestion, leading to changes in the uterus environment, which is not conducive to implantation of the egg; or the lack of blood supply to the embryo, resulting in miscarriage, the incidence of miscarriage is non-myoma women 2 to 3 times, and often incomplete abortion.

Embryos are examined and diagnosed by ultrasound or other means.

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