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Houston Fertility Journal

    Recurrent Pregnancy Loss

    February 21, 2016 / by Center of Reproductive Medicine   

    Center of Reproductive Medicine


    While reproductive medicine is primarily focused on helping a woman conceive, much of the care that is provided is centered around ensuring that the pregnancy goes full-term. The goal, of course, is to deliver a healthy baby. Statistics show that approximately 15% of confirmed pregnancies and close to 50% of all pregnancies end with a first trimester miscarriage. Usually, miscarriage is a one-time experience…


    Recurrent pregnancy loss (miscarriage) does occur, however. The phrase “recurrent pregnancy loss” or “recurrent miscarriage” is used when a woman experiences the loss of more than one pregnancy within the first 20 weeks of gestation. The loss of the pregnancy typically happens within the first trimester.


    There are several explanations for why recurrent miscarriages occur. Common reasons for recurrent pregnancy loss include the following:

    • Mismatched Chromosomes / Chromosomal Abnormalities

      Each of the cells in our body have chromosomes that include our genes. We have 23 pairs of chromosomes (23 sets from each of our parents). Sometimes, if the egg or sperm is faulty, the chromosomes are unable to line up correctly. When this happens, the embryo will have a chromosomal abnormality that often results in a miscarriage. Data shows that these mismatched chromosomes are responsible for 60% of all miscarriages.

    • Untreated Illnesses or Endocrine Disorders

      Uncontrolled diabetes and thyroid issues, such as hypo- or hyper-thyroidism are known to have an unfavorable impact on the uterus. Due to the impact that these disorders have on the uterine environment, embryos have great difficulty surviving in the womb.

    • Abnormal Uterus

      Some women are born with uterine septum - a uterus that is divided or has an abnormal shape. Miscarriages often occur with uterine septum because the embryo has difficulty implanting in the womb. If the embryo does, in fact, implant, it is unable to get the sustenance needed to remain viable. Uterine abnormalities account for approximately 10% of miscarriages.

    • Cervical Insufficiency

      A weakened cervix can also lead to miscarriage. Once the fetus has grown large enough in the first trimester, the cervix begins to swell. If the cervix is not strong enough, it cannot hold the fetus in the womb.

    • Bacterial Infection

      The male and female reproductive tracts are home to many micro-organisms. Most of these micro-organisms are both helpful and harmless, however certain particular types of bacteria do raise the risk of miscarriage. Both mycoplasma hominus and ureaplasma urealyticum bacteria can live in the reproductive tracts of both men and women who are otherwise in good health. Miscarriage often happens when women are infected with either of these particular bacteria. The bacteria inflames the lining of the uterus and the embryo is unable to develop and grow. Since there are no symptoms related to these bacterial infections, testing is the only way to determine if either partner is carrying one of these problem micro-organisms.

    • Unhealthy Lifestyle Issues

      Using recreational drugs and drinking more than two alcoholic beverages a day are known to increase the likelihood of miscarriage. In addition, smokers have twice as many miscarriages as those who do not smoke. Studies have shown that nicotine interferes with the placenta and blood supply and can severely impact fetal growth.


    Blood clotting disorders, autoimmune factors, and stress are also known to cause miscarriage. Determining the cause of recurrent pregnancy loss is difficult in close to 50% of all cases, however there are treatments available that can decrease the miscarriage risk in future pregnancies. Surgery is often used to correct abnormal uterus issues. Medication can be prescribed to treat certain endocrine and blood clotting disorders. Although it is not yet possible to make chromosomal changes in eggs and sperm, it is possible to determine embryos that are chromosomally normal versus those that are not. In an IVF process called preimplantation genetic screening, also known as PGS, reproductive endocrinologists can choose embryos that are chromosomally normal and discard those that are not. 


    Recurrent pregnancy loss is always emotionally difficult, however there is still much hope for couples with dreams of expanding their family. Successful treatments exist and they are typically successful for more than 60% of those couples who have experienced multiple miscarriages.

    Topics: Pregnancy Loss, Miscarriage

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