Signs that the placenta is beginning to separate include:

• A sudden gush of blood

• Lengthening of the visible portion of the umbilical cord.

• The uterus, which is usually soft and flat immediately after delivery,  becomes round and firm.

• The uterus, the top of which is usually about half-way between the pubic bone and the umbilicus, seems to enlarge and approach the umbilicus.

Immediately after the delivery of the baby, uterine contractions stop and labor pains go away. As the placenta separates, the woman will again feel painful uterine cramps. As the placenta descends through the birth canal, she will again feel the urge to bear down and will push out the placenta.

If the placenta is not promptly expelled, or if the patient hemorrhages while awaiting delivery of the placenta, this is called a "retained placenta" and it should be manually removed.

After delivery of the placenta, the uterus normally contracts firmly, closing off the open blood vessels which previously supplied the placenta. Without this contraction, rapid blood loss would likely prove very problematic or worse.

To encourage the uterus to firmly contract, oxytocin 10 mIU IM can be given after delivery. Alternatively, oxytocin 10 or 20 units in a liter of IV fluids can be run briskly (150 cc/hour) into a vein. Breast feeding the baby or providing nipple stimulation (rolling the nipple between thumb and forefinger) will cause the mother's pituitary gland to release oxytocin internally, causing similar, but usually milder effects.

A simple way to encourage firm uterine contraction is with uterine massage. The fundus of the uterus (top portion) is vigorously massaged to keep it the consistency of a tightened thigh muscle. If it is flabby, the patient will likely continue to bleed.

From OB-GYN 101: Introductory Obstetrics & Gynecology