How many weeks into pregnancy can a B-ultrasound be performed?

In the medical field, B-ultrasound, or ultrasound examination, is a very important diagnostic method for prenatal monitoring. It enables physicians to observe fetal development, detect possible abnormalities, and evaluate the pregnant woman's health status. Typically, ultrasound examinations are performed at the following time points:

1. 6-8 weeks of pregnancy: At this stage, embryonic tissue gradually develops into a gestational sac, and structures such as the fetal heart and embryo may become visible. Ultrasound can help assess whether the embryo is developing normally and provide information regarding fetal development.

2. Around 16 weeks of pregnancy: At this time, ultrasound is used to understand fetal growth and development and to evaluate the overall developmental status.

3. Around 28 weeks of pregnancy: A follow-up ultrasound can clearly assess the development of fetal organs and tissues, and help detect any potential fetal abnormalities or malformations.

4. From 36 weeks of pregnancy until the expected delivery date: The examination focuses on amniotic fluid volume, placental function, fetal weight, and fetal position, to predict the likelihood of a vaginal delivery.

Although ultrasound is a non-invasive and safe diagnostic method without radiation exposure, unnecessary or excessive ultrasound examinations should be avoided to prevent any potential adverse effects on the fetus.