I am almost eight weeks along in a twin pregnancy. Three weeks ago an ultrasound showed a spot in the uterus, but the babies were growing fine. A week later, another ultrasound showed one baby was weakening in growth, and we didn't hear heartbeats. Last week, the ultrasound showed both heartbeats had stopped. The spot is the same size, almost 20mm long (I think), but it seemed like it came too close to the embryos. I will have one more ultrasound to make sure, and then probably a D&C. The doctor thinks this may be a blood clot. Can that happen again? We got pregnant through fertility treatment.

S.

This spot certainly could be a blood clot, and if it was under the placentas, it could have interfered with the delivery of nutrients and oxygen to the babies, leading to miscarriage. Miscarriages, unfortunately, are very common; they occur in about 20 percent of recognized pregnancies and in half of all conceptions. (Most of these losses occur before a woman even realizes she is pregnant.) While this sounds awful, the good news is that in the overwhelming majority of cases, the next pregnancy will lead to the delivery of a healthy baby.

There are many, many reasons for miscarriages. Most often, the baby is not genetically normal and a miscarriage happens early; if these babies lived, they would be born with severe handicaps that might be incompatible with life outside the womb. Some miscarriages occur because the uterus is shaped abnormally, or there are growths such as fibroids or polyps that interfere with normal implantation of the embryo in the wall of the uterus. Others happen due to blood clotting abnormalities in the mother. These are only a few of the many causes. If a woman has one miscarriage, no further evaluation is done in most cases -- this is because miscarriage is so common and is so unlikely to happen again. If a woman has multiple miscarriages, however, a search for the reason may be undertaken, but a reason is not always found.

It is devastating to have a miscarriage, and even more so for women who have conceived through fertility treatments. I underwent fertility treatments in order to become pregnant, and I miscarried twice before having my daughter. Surround yourself with people now who are supportive and who respect the emotions you are feeling. You have suffered a loss, and it does not matter how early it occurred. I hope the best for you next time around.