D&C vs. Natural Miscarriage
Current obstetrical practice has moved away from doing a D&C for early pregnancy loss. Some obstetricians believe your body is perfectly capable of passing tissue on its own and there's no need for an invasive surgical procedure with a risk of complications. Some women have told me their doctors claimed that a D&C carried a higher risk of infection than a natural miscarriage. Biologically, that makes little sense to me, although the doctor may know something about their operation room facilities that I do not. A natural miscarriage involves intermittent opening and closing of your cervix (that could allow infectious organisms to ascend into your uterus) as well as the passing necrotic tissue. In a natural miscarriage, all the tissue may not get out of the cervix and an infection may have the potential to develop in the damaged tissue hanging out of the cervix, and move in that damaged tissue to gain access to the uterine cavity. Under standard operating room techniques where great care is usually taken to keep everything clean, this risk ought to be reduced.
A D&C may not be necessary if a pregnancy is lost very early since you won't be passing a lot of tissue. It may also not be necessary if you are able to psychologically deal with passing tissue intermittently over a number of days. From a pathologist's point of view, I would certainly prefer that a D&C be performed if you are going to use the pregnancy tissues to try to understand the cause of the pregnancy loss. With a D&C you get the tissues out cleanly and neatly and in a fashion where pregnancy and maternal tissues can be easily separated one from the other and you can get a reliable chromosome count.
In addition, if you go the natural miscarriage route, your body is going to prepare the tissues to leave your body in a way that minimizes your risk of blood loss. Your body is going to start closing down blood vessels and walling off tissues. Once those processes have begun, it's difficult for a pathologist to interpret changes in the uterine lining that may have destabilized the uterine lining and caused it to fail vs. changes your body made in the uterine lining in preparation for passing the pregnancy tissues. This is especially true for diagnosing clotting problems since clotting is such an integral part of protecting you from bleeding to death when you pass tissue. Most other issues can be assessed in naturally miscarried tissues but to insure yourself of the best and most thorough evaluation, tissues from a D&C are best.
Is it better to wait for a 'natural' passage of tissues to occur or to have a planned D&C or D&E?
The issue of natural miscarriage vs. D&C is an extremely personal one. As a pathologist who uses those tissues to try to better understand cause of pregnancy loss, the tissue from a natural miscarriage is far more difficult to use to either set up a good chromosome count (to rule out a wrong chromosome number problem) or to get a good idea of the histology of blood vessels or your immune system that could be contributing to death of a genetically viable conception. By the time tissues are "naturally" passed, there have been extensive changes made to protect you from bleeding excessively during that process.
