Blood underneath the placenta is dangerous, and the possibilities of placenta praevia, placental abruption, pre-miscarriage or preterm labor need to be ruled out.
1. Placenta praevia: As the placenta is positioned relatively low, close to or reaching the endocervical os, when the lower part of the uterus extends, the placental tissue attached to it can not extend, which will lead to separation of the edge of the placenta from the uterine wall, and the blood vessels there rupture and bleed. If the bleeding is excessive, it will lead to hemorrhagic shock and fetal distress, and even threaten the life of mother and baby,
2. Placental abruption: due to external force on the abdomen of pregnant women, or hypertensive disorders of pregnancy leading to uteroplacental vasospasm, the placenta may be detached from the uterine wall, resulting in bleeding from the placenta and other parts of the uterus. If the peeling area is too large, it will lead to excessive bleeding, and in serious cases, the life of the fetus will be jeopardized.
3. Pre-eclampsia or preterm labor: If there is blood under the placenta, there may be separation of the placenta from the wall of the uterus, which reduces the blood supply to the fetus and affects the development of the fetus; or the separation of the placenta from the wall of the uterus leads to uterine contractions, resulting in pre-eclampsia or pre-eclampsia.
Pregnant women with these conditions must seek medical attention in a timely manner so as not to miss out on their condition.