Pregnancy

The placenta plays a vital role in pregnancy, delivering nutrients and oxygen to the babies and removing their waste. In a multiple pregnancy, each baby may have his own placenta, or two babies may share a single placenta. Either way, if something goes wrong, the babies' survival is at stake.

Placenta Previa

When the placenta implants low in the uterus, covering the cervical opening, it's called placenta previa. The chances of this happening are increased when a uterus has to accommodate two or more placentas. While placenta previa does not pose a risk to the babies' development, it may cause vaginal bleeding toward the conclusion of the pregnancy, as the cervix begins to dilate and open. Bed rest may help the bleeding subside by decreasing the amount of pressure on the placenta. In extreme cases, the mother may require a blood transfusion to prevent excess blood loss. Usually she will have to deliver the babies via cesarean section.

Abruptio Placentae

Sometimes the placenta begins to detach prematurely from the wall of the uterus, a condition called abruptio placentae. While it can be caused by trauma to the abdominal region, it can also be instigated by other conditions that are common in a multiple pregnancy, such as high blood pressure. The detachment may be mild and partial, happening slowly over time, or complete and sudden. Pain and bleeding usually accompanies complete abruption; this requires immediate delivery of the babies by c-section. In more mild cases, doctors will closely monitor the pregnancy to determine the best option for the babies, weighing the consequences of early delivery. Bed rest may be recommended.

Hemorrhage

Mothers of multiples have an increased risk of hemorrhage, or uncontrolled bleeding, during their pregnancy or following delivery. Several factors contribute to the risk:

- A uterus that is stretched and strained by accommodating additional babies

- A greater portion of the surface area of the uterus covered by placental tissue

- Increased chance of undergoing cesarean section

Usually, the only consequence is heavier postpartum bleeding following delivery, but occasionally severe, uncontrolled bleeding puts the mother's health at risk.