During the early stages of pregnancy, women need to undergo medical examinations. Firstly, it is necessary to confirm intrauterine pregnancy. Secondly, it is essential to observe whether the fetal heartbeat and germinal vesicle grow normally during the early pregnancy. If there is a delay in the appearance of the fetal heartbeat and germinal vesicle, it indicates that there is a problem with the fertilized egg, and termination of pregnancy may be necessary. Typically, the fetal heartbeat is formed around 50-60 days of pregnancy.

When Does the Fetal Heartbeat and Germinal Vesicle Appear During Pregnancy?

During the development of the fertilized egg, the first two weeks are referred to as the zygote. Subsequently, various organs gradually form. Before the 8th week of pregnancy, it is referred to as the embryo (or germinal vesicle). The period from three weeks to four weeks into the first month of pregnancy is known as the germinal vesicle stage. Due to the development of the embryo, the gestational sac forms around 30-40 days, the germinal vesicle forms around 40-50 days, and the fetal heartbeat forms around 50-60 days. Therefore, generally, an ultrasound examination should be performed around 60 days to assess the normality of the gestational sac, germinal vesicle, and fetal heartbeat.

Reasons for the Absence of Germinal Vesicle During Pregnancy

1. Chromosomal abnormalities. Whether it is sperm or egg, if there are abnormalities in the chromosomes carrying genetic material, even if a fertilized egg is formed, the germinal vesicle will not develop normally.

2. Exposure to toxic substances. Harmful substances include toxic chemicals, inferior decoration materials, etc. If pregnant women are exposed to these substances, it can affect the growth and development of the germinal vesicle.

3. Exposure to radiation or a large amount of electromagnetic radiation. If a pregnant woman unknowingly undergoes X-ray exposure or receives a large amount of radiation, it can also affect the development of the germinal vesicle.