Diagnosing the Cause of Miscarriage

Before I begin, let me say that I know it is frustrating and scary to face both trying again immediately or testing for causes before trying again. Both approaches are difficult. We’d all be much happier if we could just have had that first baby without any complication. But life has already thrown us off course. Becoming a parent is not going to be easy for us, and we have to face that. 

The information here is not really my opinion, although I will throw a few in there. This is just the way the medical world thinks. I wish that when we lost a baby, we could get quick and easy testing that would tell us what went wrong, then we could do something simple that would totally prevent it from happening again. But that is not the way it works. Sometimes the only way to know there is a problem for sure is to lose another baby. I hate that, and am troubled by the practice, but the medical world goes by statistics, and here is why you may not be as aggressively tested as you would like following your first miscarriage: 

  1. After one miscarriage, your odds of another one are very small. Less than 20% of women who have miscarried will have repeated losses, so most doctors will assume that if you are healthy and had only one loss, particularly in the first trimester, that you will never have another one. This is pretty much true. 

  2. There are very few treatments to help you prevent a miscarriage. (See the section on prevention for more.) Most testing will not uncover a reason for a loss anyway, as early testing is just a shot in the dark. Even if testing showed a problem, there might not be anything more you can do than to assess the amount of risk you face for another one. The biggest bulk of miscarriages are caused by a random genetic error, which cannot be predicted or avoided. Naturally, there are a few treatable problems. It might pay to learn more about them in the causes section to see if you might be a candidate.

  3. Testing, which often yields no answers, can be expensive, time consuming, stressful, and make you wait longer to try again. Often by the time you do any of the more involved testing, such as endometrial biopsy, HSG, or laparoscopy, all of which require you to wait until a certain time in your cycle, you could be pregnant again with a healthy baby. After one loss, from a statistics standpoint, it makes sense just to try again since you will almost always have a healthy baby the next time. If you face another loss, it can make you angry that another baby had to die, and this is perfectly understandable. But this anger and determination will get you through the testing process and make you stronger as you face the results. 

That addresses the issue of testing after one loss. Some of you, however, may have special circumstances:

If you are over 35 and had one first trimester loss, you will be even less likely to get testing since the odds that your loss was a chromosomal problem with your egg are very high. There is nothing to do in this case but to keep trying for a better egg. Some doctors, however, acknowledge that older moms might have undiagnosed health problems, and will test for the more common thyroid or lupus causes.

If you have had two miscarriages in a row, or a loss after 14 weeks, you will stand a better chance of getting some testing done. Those random genetic flaws really should not strike twice in a row, and most babies with them have already been lost before the end of the first trimester. You can usually get some testing done with minimal fuss.

After three miscarriages in a row, you really should stop trying on your own. You clearly do have a problem, and you need to find it and see if it can be treated. This, of course, if only true if you have never had a healthy baby. If you have had children between the losses, the choice to test is up to you. Your problem, if you do have one, is obviously intermittent.

The Testing Process

A number of tests are easy to perform (blood test or vaginal culture only.) All but a few require that you not yet be pregnant again. If you are comfortable with your doctor and willing to fight for some testing, you can usually ask for and get the early testing ones done even after one loss:

Early Testing

Progesterone monitoring by blood test (prior to pregnancy to check for luteal phase defect, and during early pregnancy to watch for deficiencies.)

Mycoplasma bacteria culture from cervix

Antinuclear and antiphospholipid antibodies in blood

Lupus Anticoagulant in blood

Underactive or overactive thyroid by blood

Exposure to German Measles, toxoplasmosis, Group B Streptococcus, or sexually transmitted diseases even if you tested negative prior to or early in pregnancy


More Extensive Testing

Progesterone Endometrial Biopsy (a bit of lining is scraped and checked)

Hysterosalpingogram (HSG) or “dye test” (dye is shot into the uterus and fallopian tubes and then x-rayed to look for malformations, fibroids, or blocked tubes)

Karyotyping of Baby or Pregnancy Tissue (tissue is grown in a dish to watch for cell division, which will reveal the chromosomal make up of the baby)

High Level Ultrasound of Reproductive Organs


Most Extensive Testing (some are limited to specialized centers and not available to regular OB/Gyns)

Laparoscopy or Hysteroscopy (minor surgical procedures where interior of reproduction organs are inspected with a lighted scope via a belly button incision (lap) or up through the dilated cervix)

Karyotyping Parents (blood cells are cultured and grown)

Genetic Counseling

Immune Factors

Antipaternal Leukocyte Antibodies

Antithyroid Antibodies

DQ Alpha

DQ Beta


Natural Killer Cell Assay

Tumor Nerosis Factor

Factor II (prothrombin) Mutation

Factor V Leiden Mutation

Methylene Tetrahydrofolate Reductase Mutation


Special Situation Testing

Parvovirus, or Fifth Disease (a recently active virus can be looked for if you work with small children, were exposed to the illness, or had symptoms. Most adults are already immune, but this test can see if you were not and perhaps were infected during pregnancy.)

Mercury blood levels (if exposure seemed high, usually through job function)

Leave a Reply

Your email address will not be published. Required fields are marked *