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Pregnancy

I'm wondering about miscarriage ...

  1. What causes a miscarriage and how can I prevent it?
  2. Are my chances of having a miscarriage higher because I've had one before?
  3. How long should you wait after a miscarriage to get pregnant again?
  4. Is the recovery time for a miscarriage treated the same as it is after childbirth? For instance, must a person wait the required six weeks to have sex again?
  5. When a fetus dies, does the body expel the fetus immediately or is it sometimes carried around for days until that happens?
  6. How long after a miscarriage will a pregnancy test have a negative reading?

What causes a miscarriage and how can I prevent it?

Miscarriages happen for a variety of reasons such as infection, abnormal implantation of the embryo, or medical problems of the mother. The most common reason for miscarriage is abnormal chromosomal number or arrangement. Chromosomes are inherited from the mother and father. Half come from each in a very complicated process where each parent's chromosomes are divided equally and contribute to the developing embryo. Something can happen in the dividing or combining process that leads to this abnormal number or arrangement. When this happens, the embryo doesn't develop normally and is rejected by the body in the form of a miscarriage. Miscarriage occurs in about 25% of known pregnancies, and closer to 50% of all pregnancies (recognized and unrecognized). The majority (70-80%) occur as a direct result of abnormal chromosomal development.

There is nothing you can do to prevent a miscarriage, but the good news is that the majority of women who miscarry go on to have a healthy baby. The best thing you can do is to prepare for a healthy pregnancy by maintaining good health and visiting your caregiver for preconceptional counseling.

Are my chances of having a miscarriage higher because I've had one before?

Miscarriages are common (some studies suggest as high as 50% of all pregnancies) and with a first trimester loss, you are not at increased risk of having another miscarriage. The statistics (and causes of miscarriage) change if the loss is later in pregnancy. In your case, if the miscarriage occurred earlier than 12 weeks (and just not detected until 12 weeks), your risk is not changed.

How long should you wait after a miscarriage to get pregnant again?

There is no standard medical answer to your question, but most physicians suggest three months, or three normal menstrual cycles. This allows time for your uterus to return to its normal size and to resume normal menstrual periods. There seems to be an increased risk of miscarriage if women become pregnant within three months.

If any of the following are true:

I would suggest talking to your doctor before trying to conceive again to discuss preventable causes of miscarriage.

Is the recovery time for a miscarriage treated the same as it is after childbirth? For instance, must a person wait the required six weeks to have sex again?

The reason to limit intercourse until six weeks after childbirth is that is when the uterus returns to normal size. At that time, the cervix is closed and the incidence of infection of the uterus is less. After a miscarriage, the return to normal size is much shorter and therefore intercourse can be resumed in about 2-4 weeks (depending on the length of the pregnancy before miscarriage).

When a fetus dies, does the body expel the fetus immediately or is it sometimes carried around for days until that happens?

One type of miscarriage that occurs is called a missed abortion. With a missed abortion the dead embryo remains in the uterus for several weeks. Following the death of the embryo the breast changes of pregnancy begin to regress and the uterus does not continue to enlarge, and may begin to decrease in size. The reason some pregnancies end this way is unknown. If the pregnancy is of a longer duration when the fetus dies, labor usually begins spontaneously within two weeks. Occasionally this does not occur and labor will need to be induced.

How long after a miscarriage will a pregnancy test have a negative reading?

The time it takes for a pregnancy test to become negative following a miscarriage depends upon the gestational age at the time of miscarriage. For any pregnancy, whether it ends at term, preterm, or in miscarriage, a urine pregnancy test should be negative after six weeks. If it is not, there are three concerns:

  1. Retained pregnancy tissue
  2. A new pregnancy
  3. Molar pregnancy (an uncommon disorder of the placenta in which the placental tissue spreads in a potentially malignant fashion, which is highly curable with prompt recognition and treatment).

If you have had a positive pregnancy test following a miscarriage, you should discuss this with your health care provider.

For more information:

Go to the Pregnancy health topic, where you can:

This article is a NetWellness exclusive.

Last Reviewed: May 28, 2002

Arthur T Ollendorff, MD Arthur T Ollendorff, MD
Associate Professor of Obstetrics and Gynecology
College of Medicine
University of Cincinnati