Is it dangerous if the lower margin reaches the cervical os?

In general, the phrase "lower edge reaching the internal cervical os" refers to the placenta's lower edge reaching the internal cervical os. Whether this condition is dangerous mainly depends on the stage of pregnancy and the specific placental position. If the placenta's lower edge reaches the internal cervical os during early or mid-pregnancy, it is generally not dangerous. However, if this occurs during late pregnancy, it may be more dangerous. If any discomfort occurs, prompt medical consultation is recommended. Detailed explanations are as follows:

During early and mid-pregnancy, a low-lying placenta is relatively common. As the uterus enlarges, the placenta usually moves naturally upward to a safer position. As long as subsequent examinations confirm that the placental position has returned to normal, it will not affect delivery.

If the placenta's lower edge reaches the internal cervical os during late pregnancy, it may indicate placenta previa, which can pose certain risks. Placenta previa may lead to rupture of placental blood vessels, potentially causing preterm birth or difficult labor, and may also increase the risk of bleeding before and after delivery.

To ensure maternal and fetal health, pregnant women should undergo regular prenatal checkups and closely monitor any changes in placental position.