Everything you put in your body reaches your baby via the placenta.
It's not pretty, but it is very important and serves as grist for lore and ritual the world over: Some cultures bury it, some consider it the baby's sibling, some even eat it. Not only is the placenta the trading post between the mother's and the baby's blood supply, at around week 12 it takes over the production of hormones needed to sustain the pregnancy. And recent research found that its structure may even determine the length of a pregnancy.
Although the placenta usually functions flawlessly, occasionally a problem arises:
PLACENTA PREVIA: The placenta is too low in the uterus in 1 in 200 pregnancies, the March of Dimes reports. Because it can block the cervix, there can be bleeding and a Cesarean section will be required.
PLACENTAL ABRUPTION: The placenta pulls away from the uterine wall in 1 in 100 pregnancies, and this can be life-threatening to the mother and/or baby. The main symptoms are bleeding and pain, says Dane Shipp, M.D., an OB-GYN with Pacific Coast Women's Health in San Diego. An immediate C-section may be required if a mild abruption worsens, if bleeding is heavy or if the baby is having problems.
PLACENTA ACCRETA: The placenta implants too firmly into the uterine wall, a serious problem that occurs in approximately 1 in 530 births. "With the increasing number of C-sections, we are seeing this more often," Shipp says. "It usually occurs under the scar from a past uterine surgery or C-section."
If it's diagnosed before delivery, a woman usually undergoes a C-section; if it is severe enough, she may need a hysterectomy at the same time.