Placenta Problems in Pregnancy

Two terms you may hear during your pregnancy are placental abruption and placenta previa. Placental abruption is the term used to describe when the placenta detaches from the uterine wall. Placenta previa is the term used to describe when the placenta covers the mother’s cervix. These are two very different conditions, but both involve problems with the placenta during pregnancy.

PLACENTAL ABRUPTION

What are the causes of placental abruption?

     There are many causes. It’s often not possible to know exactly why a placenta begins to detach from the uterus. A common explanation is a uterine fibroid, which is a benign muscle tumor of the uterus. A placenta can detach because it is too low in the uterus which often impedes a good blood supply. Another possibility is an infection in the lining of the uterus.

What are the common treatments for placental abruption?

     In the past we confined patients to bedrest. Today, I would recommend decreasing activity; for example, for mothers who work outside the home, I recommend no work outside the home until after delivery. Pelvic rest, or decreasing activity which puts pressure on the uterus, is another recommendation.

What are the risks of for mother and baby with placental abruption?

     For mothers, two simultaneously occurring risks with placental abruption include vaginal bleeding and cesarean section. For babies, preterm birth is the most common problem. In my experience all moms and babies have survived placental abruption, although some of the babies have been preterm.

PLACENTA PREVIA

What is placenta previa?

Placenta previa occurs when the placenta begins to cover the mother’s cervix.

Are there different kinds of placenta previa?

     The placenta can impinge upon the cervix in many ways. The placenta previa can be near the cervix, covering a small portion of the cervix, covering the cervix halfway, or covering the cervix all way.

How can you diagnose placenta previa?

     The best way to diagnose placenta previa is with an ultrasound. With a placenta previa, examination of the cervix with a finger is contraindicated because there is a significant risk of dislodging the placenta and causing bleeding.

Does placenta previa occur in many pregnancies?

     Many women develop placenta previa at about 20 weeks. In my experience, it occurs at about 20 weeks in about 20 percent of pregnancies, or 1/5 of patients. There is almost no risk at this point in pregnancy,  although most obstetricians would recommend pelvic rest which is a euphemistic term for no sexual intercourse. Placenta previas at 20 weeks are mostly benign because the placenta migrates from the lower part of the uterus to the upper part of the uterus as the uterus grows. The placenta rides along the uterus searching for the best supply of blood.

If your placenta previa persists, what are the risks for the mother?

If the placenta does not migrate upwards in the uterus but remains close to the cervix, there is the risk of continued bleeding and an eventual cesarean section.

If your placenta previa persists, what are the risks to the baby?

     The good news is catastrophic placenta previa causing the death of the baby or mother is extremely rare, much less than 1 percent. Although delivery because of  placenta previa is often preterm, the pregnancy usually survives until the baby is old enough to be delivered by cesarean section. The baby may be preterm, but is old enough to do well after delivery.