Recurrent Pregnancy Loss (Recurrent Miscarriages)

Miscarriages are sadly common, with about 15-25% of pregnancies ending in loss. When a woman has a miscarriage in two or more consecutive pregnancies, however, it is referred to as recurrent miscarriages or recurrent pregnancy loss.

While miscarriages are common, recurrent miscarriages are not. According to the American College of Obstetricians and Gynecologists (ACOG) and the American Society for Reproductive Medicine (ASRM), less than 5% of women experience two miscarriages in a row. In most cases, these women will go on to have a successful pregnancy in the future.

If you have recurrent miscarriages, a physical exam and testing are recommended to help determine the cause. Your OB/GYN or fertility specialist can also provide information on support resources to help with the grief and emotional toll repeated miscarriages can take on patients and couples. 

Recurrent miscarriages may be referred to as “primary” or “secondary” pregnancy loss.

• Primary recurrent pregnancy loss occurs for women who have never given birth to a live infant
• Secondary recurrent pregnancy loss occurs in women who have given birth to a live infant before

Recurrent miscarriages may also be referred to as “early” or “late” miscarriages.

• Early miscarriages occur within the first trimester of pregnancy (13 weeks)  
• Late miscarriages occur between 14 and 20 weeks
• After 20 weeks gestation, a pregnancy loss is considered a stillbirth

Most miscarriages (80%) occur during the first trimester. Less than 5% of miscarriages occur during the second trimester. The potential causes of recurrent miscarriages can vary based on when the pregnancy loss occurs.

In most cases of recurrent miscarriage, no definitive reason for the pregnancy losses will be found. In cases where a cause is found, some potential causes of recurrent miscarriages include:

• Genetic abnormalities. Many first-trimester miscarriages occur when an embryo has an abnormal number of chromosomes (known as aneuploidy). The risk for random or non-inherited chromosomal abnormalities in a developing embryo increases with maternal age. There can also be inherited chromosomal abnormalities, known as “translocations,” where a piece of one chromosome breaks off and moves to another chromosome. These translocations likely make up less than 5% of all cases of recurrent pregnancy loss.
• Uterine abnormalities or conditions. Recurrent miscarriages may occur if the woman has a congenital disorder that affects the structure or shape of her uterus or the woman may have other uterine conditions such as fibroids, polyps, or scarring and adhesions. Problems with the uterus occur in about 10-15% of women with recurrent pregnancy loss.
• Medical conditions. Untreated, some medical conditions can increase the risk of recurrent miscarriages, including diabetes mellitus, thyroid disease, and antiphospholipid syndrome (APS). APS is an autoimmune disorder that can lead to abnormal blood clotting and is thought to occur in about 15% of cases of recurrent pregnancy loss. 
• Environmental and lifestyle issues. Other factors that may increase the risk of repeated miscarriages include exposure to toxic substances in the environment, radiation, and behavioral issues like cigarette smoking, illicit drug use, excess alcohol use, excessive caffeine intake, obesity, and certain types of infections.

Diagnosing the cause of recurrent miscarriages starts with a thorough medical history, including a detailed discussion of past pregnancy losses, and a physical exam. A pelvic exam may also be performed.

Testing may include:

• Imaging tests to examine the uterus and uterine cavity for congenital anomalies or other uterine conditions. This is often done through an ultrasound procedure (called a sonohysterogram) 
• Blood tests to check for diabetes, thyroid disease, hormonal issues, and autoimmune conditions
• Genetic testing of both parents 
• Genetic evaluation of miscarriage tissue from pregnancy loss, if available

About half of all cases of recurrent miscarriages are unexplained, meaning no clear cause is identified.

• Genetic counseling and testing
• Surgery to correct congenital anomalies of the uterus or to remove uterine fibroids, polyps or scarring in the uterine cavity
• Medications to treat and manage maternal health conditions that increase the risk of recurrent miscarriages
• In vitro fertilization (IVF) with preimplantation genetic testing, where the eggs and sperm are combined outside the body, and the fertilized embryos are genetically tested for specific conditions before being placed in the woman’s uterus

If you have suffered recurrent pregnancy loss, call 832-826-7272 to make an appointment with a Baylor College of Medicine reproductive endocrinology and infertility (REI) specialist. They will perform a thorough workup to try and find any potential causes along with discussing potential therapies.