What is the reason for fetal arrest before the full term of pregnancy?

Pregnancy for 10 months is a very difficult process. During pregnancy, not only will women experience early pregnancy reactions, but symptoms of morning sickness will bother women for about three months. During these three months, they dare not eat anything every day, and their stomachs will be damaged due to frequent vomiting for a long time. After three months, they will reach the second trimester. In the second trimester, the appetite will increase and the belly will slowly grow. In addition to bearing its own weight every day, the human body also has to bear the weight of the belly. This is undoubtedly the weight of two people every day, so pregnant women gradually develop swollen legs. In many people in early pregnancy, doctors often tell them that the fetus has stopped growing during examinations. This is mainly due to poor development, which leads to the cessation of development. It may also be related to some factors and requires timely diagnosis.

reason

Fetal arrest refers to the cessation of embryo development due to some reason in early pregnancy. Ultrasound examination may show an irregular fetal bud or fetal shape in the gestational sac, no fetal heartbeat, or a withered gestational sac. Clinically, it falls into the category of miscarriage or stillbirth. There are many reasons for fetal growth retardation. More than 90% of them are related to abnormalities of the embryo itself. In a few cases, they are related to luteal insufficiency, hyperprolactinemia, abnormal thyroid function, and diabetes.

Endocrine disorders

Embryo implantation and continued development depend on the coordination of a complex endocrine system. Any abnormality in any link can lead to miscarriage. During the early development of the embryo, three important hormone levels are required: estrogen, progesterone, and human chorionic gonadotropin. As for the mother, if her own endogenous hormones are insufficient, it cannot meet the needs of the embryo and may cause embryo arrest and miscarriage. The most common of these is luteal dysfunction, which can cause delayed endometrial development and a short luteal phase, thereby affecting the implantation of the fertilized egg or early pregnancy miscarriage. People with luteal insufficiency are often accompanied by other glandular dysfunctions, such as hyperthyroidism or hypothyroidism, diabetes, relative androgenism and hyperprolactinemia. These factors are not conducive to embryonic development and are closely related to miscarriage.

Uterine abnormalities

Both the internal environment of the uterus and the overall environment of the uterus may have an impact on the embryo. The internal environment is the endometrium. If it is too thin or too thick, it will affect implantation. About 10% to 15% of miscarriages are caused by uterine defects. Common ones include (1) congenital abnormalities of the Müllerian duct, including unicornuate uterus, didelphic uterus, septate uterus, and bicornuate uterus, which result in a narrow uterine cavity and restricted blood supply. Abnormal development of the uterine arteries can lead to asynchrony of decidualization and abnormal implantation. (2) Intrauterine adhesions, which are mainly caused by intrauterine trauma, infection or residual placental tissue, leading to intrauterine adhesions and fibrosis. Hinders normal decidualization and placental implantation. (3) Uterine fibroids and endometriosis cause reduced blood supply, leading to ischemia and venous dilatation, asynchronous decidualization, abnormal implantation, and hormonal changes caused by fibroids, which can also cause pregnancy failure. (4) Congenital or traumatic cervical relaxation and abnormal cervical development caused by intrauterine treatment with diethylstilbestrol often lead to mid-term miscarriage.

Chromosome problems

If the chromosomes are abnormal, it may cause the embryo to not develop and lead to early miscarriage. Chromosomal abnormalities include quantitative and structural abnormalities. Quantitative abnormalities can be divided into aneuploidy and polyploidy. The most common abnormal karyotype is aneuploid trisomy, and trisomy 16 accounts for 1/3 and is often lethal. 25-67% of pregnancies with trisomy 21, 4-50% of pregnancies with trisomy 13, and 6-33% of pregnancies with trisomy 18 are bound to result in miscarriage. Others include haploid (45, XO) and tetraploid, which result in embryonic underdevelopment due to abnormal cleavage. Structural abnormalities include deletions, balanced translocations, inversions, overlaps, etc.

If one of the spouses has a balanced chromosomal translocation, it is easy for the embryo to have chromosomal abnormalities and cause embryonic arrest. The mechanism by which the embryo's chromosomal abnormalities occur is that when the couple's chromosomes fuse, chromosomal fragments are easily lost or duplicated, which leads to chromosomal abnormalities in the fertilized egg and failure to develop normally, which can lead to miscarriage, stillbirth, and deformed babies. Therefore, couples with chromosomal translocation need to undergo prenatal diagnosis in the second trimester to prevent the birth of children with chromosomal diseases. Theoretically, couples with chromosomal abnormalities have the chance of giving birth to normal karyotype and carrier babies. Prenatal diagnosis can be performed on these couples to ensure the birth of normal babies.

Abnormal genetic material carried by sperm can cause embryonic arrest, but abnormal sperm refers to the appearance of sperm and not the genetic material carried by sperm. Sperm morphology assessment is used to evaluate male fertility. Abnormal sperm refers to sperm that has no chance of meeting the egg under natural conditions. Therefore, it does not matter whether the abnormal sperm carries normal genetic material. Therefore, there is no relationship between abnormal sperm and spontaneous abortion. The sperm deformity rate is a percentage of semen indicators and must be evaluated in conjunction with the total number of sperm when evaluating the sperm deformity rate.