Miscarriage is the unplanned loss of a pregnancy prior to the 6th month.  Understandably, most women (and their partners) feel disappointment at the abrupt end of their hopes for that pregnancy.  These women often find some solace in the fact that having a miscarriage is fairly common.  Many of their friends and acquaintances have likely experienced a miscarriage first-hand because about one out of four pregnancies unexpectedly ends this way.  The rate increase to about 50% in women over the age of 40. 

Pregnancy loss can occur at various times in gestation.  Often it occurs as early as a few days after the missed period.  Other times miscarriage does not occur until after the pregnancy can be visualized by ultrasound or even after the fetal heart beat can be heard.

It is almost never the case that some inadvertent action on the part of the woman causes the pregnancy loss; however, it is easy for a woman to falsely blame herself for the miscarriage.  We would like to dispel some of the myths around miscarriage.  It is NOT true that working outside the home, carrying heavy groceries, or having sex can cause a miscarriage.  We repeat, "The above activities are NOT the cause of a miscarriage."

So what problems can cause miscarriage?  Having a medical illness such as diabetes or lupus can increase a woman's risk for miscarriage.  But most miscarriages are due to a problem with the fetus itself.  Studies indicate that approximately 70% of pregnancy losses are due to chromosomal imbalances in the fetus.  Chromosomes are the separate packages that contain our genes.  Such imbalances are an unfortunate random event causing an abnormal pregnancy.  However, if a woman has 2 miscarriages in a row and desires to have a baby, it is advised that she seek medical attention from her Obstetrician or a specialist in Reproductive Endocrinology.  A fairly simple evaluation may uncover a cause of her repeated pregnancy losses.  An evaluation is recommended after only one miscarriage if the pregnancy loss occurred fairly late (after the 3rd month).  Abnormalities in the uterus (womb), cervix (mouth of the womb), thyroid hormone levels, or egg maturation are just some of the correctable causes of frequent miscarriages.

The uterus must serve as a safe incubator for the growing fetus.  However, some women have a fibroid, septum or scar tissue inside the uterus which interferes with the proper growth of the fetus.  Fortunately, these abnormalities can be removed by a surgical procedure called a hysteroscopy (similar to a D&C), thus allowing the woman to go on and have a normal pregnancy in the future.  If a woman was exposed to a medication called D.E.S. when she was in her mother's womb, she is at risk for having an underdeveloped uterus which can lead to miscarriage.  D.E.S. was sometimes prescribed for pregnant women up until the mid 1960's to prevent recurrent miscarriages.  The use of a cervical stitch called a cerclage is sometimes used to decrease the risk of pregnancy loss in these women.

A cerclage is also useful in cases where the cervix is too weak to hold the pregnancy in place.  This condition is called cervical incompetence.  Miscarriages due to this condition occur after 14 weeks gestation.

A thyroid gland that is either under-active or over-active can cause miscarriage.  A simple blood test is needed to make this diagnosis, and then supplemental thyroid hormone is prescribed by her physician to correct this matter.  Another simple blood test that should be offered is to check for certain antibodies that can lead to the clotting of blood vessels to the placenta which nourishes the fetus.  The test is called an anticardiolipin antibody with anticoagulants (ACA) assay.  The condition is called Antiphospholipid Syndrome (APS).  Fortunately, once the diagnosis is made, treatment (guided by her physician) can be initiated in future pregnancies to reduce the chance for another miscarriage.

Checking the chromosomes of the woman and her partner is another test that is frequently offered to patients who have had recurrent miscarriages.  It can detect cases where the man or woman have chromosomes that increase the chance for the fetus to inherit an unbalanced set of chromosomes - a situation which is usually not compatible with continued fetal growth.

Some woman do not reliably ovulate (release an egg) each month.  These women often have PCOS (Polycystic Ovarian Syndrome).  When these women do ovulate, the egg is often not fully ripened - leading to an embryo that is more likely to stop growing.  The adequacy of ovulation can be tested by either a blood test for progesterone a week after ovulation or by a biopsy of the endometrium (the lining of the uterus).

In at least half of the couples who undergo an evaluation for recurrent miscarriages, there is no identifiable cause.  The good news is that these couples have an excellent chance for having a normal baby with their next pregnancy.  Their chance for a normal pregnancy is very similar to that of a couple who has never had a miscarriage.  So our advice for such couples is to try again and not to lose hope.  Sometimes it is helpful for the couple to seek counseling to help cope with the grief they are experiencing.  It is safe to try to conceive again 2 or 3 months after a miscarriage (sometimes even sooner if the loss was very early).  Future pregnancies can be monitored closely with hormone assays and early sonograms.  If another miscarriage occurs, we recommend that any miscarriage tissue (passed spontaneously or obtained at the time of a D&C) be examined for a chromosomal imbalance.  A positive finding of an imbalance will give the couple the answer they are often looking for, "What went wrong this time?"

What else can a woman do to help avoid another miscarriage?  She should avoid smoking cigarettes and limit her caffeine intake to no more than 2 caffeinated beverages per day.   Even before a woman wants to try to conceive she should take folate (a vitamin) which is critical for the early growth of the embryo.  One milligram should be taken every day.  Your physician will tell you if you need other special medication like progesterone or baby aspirin.  Most treatment is individualized depending on the specifics of the case.

Though miscarriage can be emotional devastating, it is a common occurrence, and there is a very high chance that the next pregnancy will be normal.  Your concerns can often be alleviated by asking your doctor.  Therapy is sometimes recommended and is usually successful.