Infertility is not always about not being able to get pregnant. Sometimes it's also about not being able to maintain the pregnancy long enough to deliver a baby. Miscarriages are devestating when you are trying to create your family. When more than one miscarriage occurs, we refer to that as "recurrent pregnancy loss". Please read below for further information. Tomorrow's blog will focus on the other, less medical aspects of recurrent pregnancy loss, including the specific ways that you can manage this type of infertility.
In all women, 15-25% of all clinically-diagnosed pregnancies end in spontaneous miscarriage and recurrent pregnancy loss (RPL) affects 2-4% of reproductive-aged women. The definitions for the diagnosis of RPL are:
- Two consecutive first trimester or early second trimester miscarriages with fetal heartbeats
- One or more second or third trimester miscarriages that are not explained by an obvious correctable source
Recurrent pregnancy loss causes anxiety and fear in couples seeking to build their families after several miscarriages. It is important to note that successful outcomes will occur for more than two-thirds of all couples with RPL, regardless of their reproductive histories.
RPL has many possible causes, but in up to 50% of cases no specific medical cause can be detected. This is termed idiopathic or unexplained RPL. Your physician at RMACT will thoroughly investigate all possible etiologies, including genetic, hormonal, anatomic, immunologic, microbiologic and thrombophillic (blood clotting disorders) causes. These will be explained below.
Unexplained RPL can lead to intense emotions such as frustration, anger, guilt and depression. Often patients blame themselves inappropriately. It is important to keep in mind that these feelings are normal, and there are many resources available in our office to support you personally and emotionally. Patients should be reassured that exercise, sexual intercourse or eating unhealthy foods do not cause miscarriages.
Treatment plans vary by the diagnosis made. Any correctable conditions should be aggressively treated. In those cases where no specific diagnosis can be made, studies have shown that weekly monitoring and support of early pregnancy supplementation of progesterone and estrogen if indicated, can improve the miscarriage rate and empower patients.
Causes of Recurrent Pregnancy Loss
- Parental genetic causes: In the general population, approximately 1% of people have stable structural abnormalities of their chromosomes. This group of conditions likely does not impact the health of that individual but can lead to the production of abnormal sperm and eggs. These types of abnormalities typically involve having a piece of one chromosome break off and reattach itself to the wrong chromosome and are called translocations.
Studies on couples with translocations have shown a high number of miscarriages. Treatment options for RPL include genetic counseling, early amniocentesis or chrorionic villi sampling (CVS) or the use of donor sperm or eggs. Recent studies have shown that patients with recurrent loss due to genetic factors may benefit from an advanced treatment option called pre-implantation genetic diagnosis (PGD), which involves the biopsy of an embryo derived from IVF (using your own sperm and eggs) to study the chromosomes of that embryo and find the chromosmally normal one. Using this technique, we can select the normal embryos for transfer and increase the implantation rates while decreasing the miscarriage rate.
- Embryo genetic causes: This is the mostly likely reason for pregnancy loss which is secondary to improper development of the early embryo. This occurs when the normal complement of 46 chromosomes is not present and therefore a healthy child cannot develop. For couples with RPL, chromosomal analysis of the miscarriage itself can provide useful information.
- Hormonal or systemic causes: Approximately 10% of RPL patients will have a hormonal disorder associated with their losses. This includes untreated hypothyroidism (and possibly hyperthyroidism). Patients with known thyroid disease will need to have their TSH levels followed closely and will likely need to have their doses adjusted during pregnancy. Unrecognized or poorly controlled diabetes, and even pre-diabetes, increases the miscarriage rate. This rate is reduced to a normal level once sugar and insulin control is normalized. Lastly, deficiencies of progesterone, the hormone that supports early pregnancies, can lead to miscarriages. This is sometimes termed luteal phase deficiency. Treatment involves supplementing with progesterone during the first trimester.
- Anatomic causes: Developmental anomalies of the uterus are called mullerian anomalies. The most common abnormality associated with RPL is the septate uterus, where a fibrous ridge of tissue protrudes into the endometrial cavity, or womb. Removal of this uterine septum by minimally invasive surgery called hysteroscopy has been shown to improve delivery rates. Other mullerian anomalies, such as bicornuate and unicornuate uterus, are associated more with later-trimester losses or preterm birth and are much less amenable to surgical repair.
- Auto-immune causes: Anti-phospholipid syndrome is a very specific diagnosis with strict diagnostic criteria. It involves your immune system attacking the placenta or placental blood vessels that can lead to miscarriages and poor pregnancy outcomes. Treatment includes blood-thinning injections and low doses of aspirin. Historical treatments with steroids or with infusions of immunoglobulins to treat a suspected or theoretical immune system problem do not have any benefit and have been shown to worsen maternal and fetal outcomes in pregnancy.
- Infectious causes: There have been some studies in the past that have implicated asymptomatic infections of the uterus with RPL. These may include mycoplasma, ureaplasma, Chlamydia and others, but current data does not support these associations to be a strong cause of RPL.
- Thrombophillic causes: This class of blood-clotting disorders is called thrombophillias, meaning "love of clotting" in Latin. It is associated with RPL by causing small clots to form in placental blood vessels that impair the full implantation and function of the placenta. Thrombophillias can also cause blood clots anywhere in your body and may have serious health consequences. Blood tests will help your physician diagnose these conditions and formulate a treatment plan.
- Lifestyle causes: Tobacco use has a detrimental effect on pregnancy outcomes and increases the rate of miscarriage. Smoking greater than 15 cigarettes per day increases the miscarriage rate approximately 1.5 times. Alcohol consumption beyond 10 drinks per week may increase the miscarriage rate by a factor of 2 compared to non-drinkers. Smoking and drinking to excess may worsen the effects of each alone. In addition Obesity has been associated with markedly higher miscarriage rates and poor pregnancy outcomes.