D & C vs. Natural Miscarriage

by Carolyn Salafia, MD, Ph.D.

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 and 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.

What should I do with my tissue if I have a planned D&C or D&E?

There are two types of testing that can be done on miscarriage tissues:
(1) Chromosome counts (karyotyping), and
(2) Histopathology examination.

What you need to know about:

Chromosome counts (karyotyping) --
They are costly tests.
They must be performed on fresh tissue as close to the time the tissue leaves your body as possible.
The laboratory must be knowledgeable in selecting placental from uterine lining tissues for the study; otherwise YOUR tissues may be counted in error and a "normal female" result is uninterpretable.

Histopathology examination --
This is comparatively inexpensive (and preparation and archiving of slides in your local laboratory "just in case the future might give us reason to want to see them" is covered by most insurances).
Tissues are placed in formalin (a preservative) and can be sampled for histopathology study days or weeks later.
BUT pathologists still believe their only service in pregnancy loss is to confirm the fact that "yes, you were pregnant". This means that the number of tissue samples taken tends to be sparse, and the diagnosis often simply describes that a pregnancy was present.

Our laboratory does not perform chromosome counts. We can, in studying archived tissues, evaluate features that would increase or decrease the chances that a pregnancy was chromosome-wrong-number (but we cannot count the chromosomes).

If you do not desire chromosome counts, your tissues will be placed in formalin in most hospitals; in private MD offices, you may need to discuss what is done with your tissues up front with your doctor. We can receive the slides made from your tissues by your local laboratory, the tissues themselves (appropriately preserved in formalin), or both for our review. Laboratories generally keep tissues left over from their own sampling for some (variable) time after sign-out. It may be worth a phone call to see if any additional tissues still exist that could be more thoroughly examined.

Some of our patients have found out in hindsight that tissues were not sent for histopathology. In some settings (many hospitals), sending tissues taken from surgery to histopathology may be part of the hospital laws. In other settings, physicians, so used to getting reports that only confirm the fact that their patient was pregnant, may not routinely send tissues for this type of study.

If you have lost pregnancies before, you may think about whether you would like to have tisse samples archived on slides for future studies that you might choose, depending on what the future holds for you and your family. If you were treated during this pregnancy for pregnancy loss, examining the lost tissues (especially with chromosome countings) should be able to help your doctor determine if your treatment was correct or not correct, and help you prepare for "next time". If it's your first pregnancy loss, it may simply be "playing it safe" to make sure that tissues could be examined in the future if necessary.

Carolyn Salafia, M.D., Ph.D., is board certified in Anatomic and Clinical Pathology and in Pediatric Pathology. She is a world-reknown expert on pregnancy loss and is one of a small handful of pathologists in this country who specialize in reproductive pathology. For more information, see her website, www.earlypath.com. To set up a consultation or have your slides reviewed by Dr. Salafia, you can call her office at 914-834-2598.
Note: This communication is for educational purposes only and should not be used as a substitute for a consultation with your physician.