Running for my Mom

This happens when the placenta is implanted in the lower segment of the uterus instead of the upper part. It lies in front of the baby as she comes to descend the birth canal at the start of labor. The baby cannot pass down the canal without dislodging the placenta and interrupting her own blood supply. Placenta previa is a major cause of bleeding after the twentieth week and of hemorrhage in the final two months of pregnancy. It’s more common in women who’ve had several children, but the cause is unknown.

The greater the proportion of the placenta lying in the lower uterine segment, the greater the likelihood of complications during delivery. Even though the growth of the placenta in both size and weight slows down after the thirtieth week of pregnancy, the lower segment of the uterus is increasing in length quite rapidly. There may be shearing stresses between the placenta and the uterine wall, leading to episodes of bleeding.

This extremely dangerous condition can be diagnosed well ahead of delivery by ultrasound. Early symptoms include bleeding, with bright red blood, which may happen after sex. The doctor will advise a mother with these symptoms to go into the hospital for ultrasound examination and bed rest, with blood transfusions if necessary. She should continue to rest in bed, if possible, until the thirty-seventh week, when the baby will be delivered by cesarean section.

There may be a postpartum hemorrhage after the birth, but this is usually anticipated, and drugs to prevent it will be given as soon as the baby is born. In a very few cases, hemorrhage will continue despite treatment, and then a hysterectomy may be a possibility. For these reasons, placenta previa should only be treated by obstetricians qualified to cope with these complications. The mother deliver in a well-equipped hospital, with a blood transfusion service on hand.