Miscarriage Recurrent Pregnancy Loss
Miscarriage occurs in fifteen to 20 percent of all pregnancies, and the risk of miscarriage increases with each successive pregnancy loss. Recurrent pregnancy loss (RPL) is defined as three or more consecutive miscarriages that occur prior to the ability of the fetus to survive on its own (usually twenty weeks).
If a patient has had two successive miscarriages, the chance for miscarriage in the third pregnancy increases to 37 percent and initiation of a diagnostic evaluation may be considered. Although many causes of RPL are unknown, more than 60% of patients have a specific cause which is amenable to diagnosis and often to treatment.
RPL can be the result of a wide variety of conditions. The workup may be quite complex and involve many tests. Several possible causes must be considered including genetic (chromosomal) defects (almost 50% of cases), metabolic/endocrine problems such as diabetes (~15%), uterine/reproductive tract abnormalities (~10%), autoimmune disorders such as lupus or antiphospholipid syndrome (less than 10%) and lifestyle factors (e.g. smoking, alcohol intake).
More Information on Miscarriage from the Children’s Hospital of the King’s Daughters
Chromosomal abnormalities – Found in more the 50% of spontaneous abortions but in less than 1% of full-term newborns. The most prevalent type of genetic abnormality in abortuses is autosomal trisomy (50%), especially trisomies 16, 18 and 21 (Down syndrome). In about 5% of couples with RPL, one partner is found to have a balanced translocation (some of the genetic material from one chromosome is located on the wrong chromosome) and when this is passed on to the fetus genetic error can occur.
Metabolic/Endocrine Disorders – Account for more than 15% of cases. The most common causes include hypothyroidism (thyroid gland not functioning normally), diabetes (poor blood sugar control) and luteal-phase defect (inadequate progesterone production). The maternal environment is critical for fertility and for maintaining a pregnancy once conception has occurred. These disorders are diagnosed by blood work to measure hormones levels. Hormone replacement, optimization of blood sugar levels or progesterone treatments may indicated.
Reproductive Tract Defects – Uterine factors account for 10% of cases of RPL and are either congenital (from birth) or acquired. Congenital uterine anomalies include mullerian tube defects (abnormally shaped uterus or cervix). Acquired defects include intrauterine adhesions, fibroid tumors, tubular damage and cervical changes due to previous surgeries (e.g. cone biopsies or LEEP procedures). Surgery prior to attempting pregnancy may help improve the chances for a successful pregnancy.
Autoimmune disorders – Account for less than 10% of RPL cases. The most common causes include systemic lupus erythematosus (SLE), antiphospholipid antibody syndrome, parental histocompatibility local antigen (HLA) similarity and maternal antisperm antibodies. Most of these disorders are diagnosed by blood work to assay antibody levels. Depending on the causes identified, low dose aspiring or an injectible blood thinner may help in future pregnancies.
Patients with a history of RPL are often referred to Maternal-Fetal Medicine specialists for medical care. Unfortunately, sometimes no cause can be identified. However, depending on the etiologies identified in a given patient, pregnancy care can be quite complex in order to achieve a healthy outcome.
More information from the Children’s Hospital of the King’s Daughters
This information is not intended to substitute or replace the professional medical advice you receive from your physician. The content provided on this page is for informational purposes only, and was not designed to diagnose or treat a health problem or disease. Please consult your physician with any questions or concerns you may have regarding a medical condition.