Recurrent Pregnancy Loss
December 01, 2012 |
By: Wendy Schillings, MD, FACOG
Early pregnancy loss, or miscarriage, occurs in about 15-25 percent of all pregnancies. Many early miscarriages occur before a woman even knows she is pregnant.
More than half of these early losses are related to chromosomal (genetic) abnormalities in the embryo. Chromosomal abnormalities and miscarriage rates increase as women age, with miscarriage rates for women over 40 reaching 50 percent.
Recurrent pregnancy loss (RPL), defined as two or more confirmed miscarriages, is much less common. About 5 percent of women will have two consecutive miscarriages and 1 percent will have three or more. Couples experiencing recurrent pregnancy loss often feel hopeless, frustrated and confused. Reproductive experts recommend a thorough evaluation with an OB/GYN or reproductive endocrinologist to rule out any treatable causes of recurrent pregnancy loss. Treatable causes can be divided into five categories: genetic, anatomic, hormonal, autoimmune, and lifestyle.
In 2-5 percent of recurrent pregnancy loss, a pre-existing genetic defect is present in one of the parents. This defect, called a balanced translocation, occurs when a portion of one chromosome attaches to a different chromosome. Because it is balanced (all the genetic material is present), the parent appears normal. When the genetic material is passed to the egg or sperm, the resulting embryo has too much or too little genetic material, resulting in an abnormal embryo and subsequent miscarriage. This condition can easily be diagnosed through a simple blood test called a karotype. One treatment option is IVF with chromosome testing
of embryos before they are placed in the uterus.
Other conditions, collectively known as thrombophphilias, are inherited defects in blood clotting that can increase a woman’s risk of developing blood clots. Testing for and treatment of these conditions is highly controversial. Speaking with a reproductive/infertility specialist is highly recommended in women with a personal or family history of blood clots.
Abnormalities in the uterus can increase the risk of miscarriage. Some abnormalities are present from birth, occurring in about 3-5 percent of women. Other abnormalities, such as uterine fibroids or polyps, are found later in life. These abnormalities are often diagnosed during routine testing. Common tests include ultrasound, hystersalpingogram (HSG) and/or saline sonogram (SIS). A skilled reproductive surgeon can correct many anatomic abnormalities.
Endocrine (hormonal) disorders such as hypothyroidism, hyperthyroidism, diabetes and hyperprolactinemia can lead to recurrent pregnancy loss if not treated. It is important to diagnose and treat these disorders prior to conception as it can take several months to get hormone levels in a normal range.
A luteal phase defect is another hormonal disorder. Progesterone, a hormone produced after ovulation, helps maintain the pregnancy and uterine lining. When progesterone levels are lower than normal, premature shedding of the uterine lining can occur. This condition can be diagnosed by measuring the amount of progesterone in the blood after ovulation. If the level is low, supplemental
progesterone can be given.
Some pregnancy losses are caused by the production of antibodies which abnormally increase the formation of blood clots in the placenta. This condition, antiphospholipid antibody syndrome (APS), is diagnosed through a series of blood tests. Experts agree that any woman with a history of a blood clot, a late pregnancy loss (after 10 weeks) or three consecutive early losses should be screened for APS. Treatment can include baby aspirin or other medications to prevent blood clots during pregnancy.
associated with a higher incidence of RPL include cigarette smoking, obesity, cocaine use, alcohol consumption (more than 3-5 drinks per week) and caffeine use (more than 3 cups per day).
Several recent studies have identified a possible psychological cause for recurrent pregnancy loss. These early studies show higher birth rates among those with a history of recurrent pregnancy loss who received psychological support, frequent ultrasounds and more detailed teaching regarding areas such as lifting, sexual activity, and travel. Couples with recurrent pregnancy loss may benefit from counseling and support groups.
Certain organisms, including mycoplasma, ureaplasma, cytomegalovirus, chlamydia, rubella and herpes are more prevalent in women experiencing RPL. However, there is no evidence that these infections cause RPL and routine screening is not recommended.
Although a specific cause for RPL can guide treatment, up to 50 percent of cases will not have a clearly defined cause. Some treatments may be controversial. It is important for couples with a history of RPL to see a reproductive endocrinologist/infertility specialist
to have an appropriate evaluation.