How to Prevent Pregnancy Loss and Recurrent Miscarriages

Part One: Identifying the Underlying Causes

Pregnancy Loss

Truly Understanding Pregnancy Loss

Practicing Obstetrics and Gynecology for the last 18 years has taught me many things that I didn’t learn in four years of medical school and four more years of residency training. One area in particular, was related to truly understanding and treating pregnancy loss.

I will never forget the day that a patient, whom I did not know very well (she typically would see one of my partners for pregnancy visits), was in to see me because she hadn’t felt her baby move in 24 hours.  She was 35 weeks pregnant. In the majority of these cases, the baby is absolutely fine and it is only a false alarm.  Sadly, this was not the case with my patient.  I tried to find the heart beat with the mini-ultrasound monitor placed on her belly, however after a few minutes of searching, I couldn’t hear anything.  I quickly brought her into an ultrasound room to visually identify the heart.  She saw the look on my face when I visualized the baby’s chest, but could not locate any heart movement.  Nothing prepares you for how to handle that situation or how to even remotely begin to help that woman navigate the steps to follow.

Even more commonly, I have also been the bearer of devastating news when a patient comes for a routine first trimester ultrasound only to find that her pregnancy is no longer viable and the baby had stopped developing several days or weeks before.

In both of these clinical situations, I felt a tremendous sense of inadequacy as a physician. Not only because there is no way to minimize the grief the patient is experiencing, but also because the ability to reassure the patient that her next pregnancy will be okay is simply not always the case.

For anyone who has had a prior pregnancy loss, it makes sense to want to search for a reason or cause to explain WHY the loss occurred and if this could be prevented in the future.  Knowing this kind of information could offer some peace to the patient who has suffered such losses and allows them to move through their grief with at least some sense of security that their future attempts to conceive will likely not result in a similar pregnancy loss.


Statistically speaking, 15-25% of all clinically recognized pregnancies may result in a miscarriage.  It is so common, in fact, that it is recommended that clinicians avoid initiating a work-up of a miscarriage if the patient has only experienced one loss.  The Practice Committee of the American Society for Reproductive Medicine defines Recurrent Pregnancy Loss (RPL) as two or more failed clinical pregnancies.  The good news is that fewer than 5% of women will experience 2 consecutive miscarriages and only 1% experience 3 or more (1).


15-25% of clinically recognized pregnancies may result in a miscarriage

Reproductive Medicine defines recurrent pregnancy loss (RPL) as 2 or more failed clinical pregnancies


Fewer than 5% of women will experience 2 consecutive miscarriages...


Only 1% of women experience 3 or more consecutive miscarriages


This is a very frustrating question for clinicians and patients.  Following a detailed medical, surgical, family and genetic history with physical exam and laboratory testing, more than 50% of couples who investigate the cause of miscarriage or pregnancy loss will not find an answer to explain why they have miscarried (1).  This is not necessarily related to lack of scientific knowledge in this area, but most likely related to the complexity of the reproductive process, with a very intricate interplay of genetics, environment, maternal physiology, and hormonal and metabolic factors.  The standard evaluation looks for the following issues (2):

1.  Abnormal Genetics:

Approximately 60% of early pregnancy losses are associated with chromosomal abnormalities.  The chromosome carries genetic information.  Abnormalities may occur “sporadically” (by chance), if the cell division process is disrupted OR if one parent carries a specific defect called a “balanced translocation” that can result in an abnormal amount of genetic material being passed on to the fetus.

2.  Birth Defects:

18% of patient with a normal chromosomal pattern may have significant abnormalities in fetal anatomy — often times these defects are in and of themselves incompatible with life (such as a severely abnormal heart defect) or are an external sign of subtle genetic mutations that put the pregnancy at high risk for early miscarriage.

3.  Abnormally Shaped Uterus:

This may be related to later stage pregnancy losses due to preterm labor or cervical weakness.

4.  Anti-Phospholipid Antibody Syndrome:

An autoimmune condition in which antibodies attack fats in the blood, making the blood “stickier” and more likely to clot.  These antibodies may prevent proper implantation of the pregnancy or may interfere with adequate blood flow through the placenta.

5.  Other Blood Clotting Problems:

Such as factor V Leiden, Prothrombin gene mutation and protein C and protein S deficiency.  These are more likely related to losses that occur after 14 weeks of pregnancy.

6.  Environmental Or Occupational Exposures:

May result in early miscarriage due to toxic fumes, chemicals and solvents encountered in the work environment or at home.  This includes toxic exposures through smoking, excessive alcohol intake, inhaled gases (anesthetic agents), paints, gasoline, cosmetics, etc.

It is clearly worthwhile to undergo the standard evaluations to assess known causes of miscarriage, as previously mentioned, 50% of the time an important predisposing factor will be uncovered and treatment recommendations would be based on the underlying cause.  However, if a standard evaluation fails to uncover the reason for such losses (otherwise known as Unexplained Recurrent Pregnancy Loss), it is important to consider other factors not typically acknowledged in conventional medical circles.  

Next: How to Prevent Pregnancy Loss and Recurrent Miscarriages

Part One: Identifying the Underlying Causes – Page 2


How Do I Know If I Should Investigate Further?