Abstract and Introduction
Miscarriage is a relatively common occurrence for otherwise healthy women. Despite its frequency, evaluation for cause is rare. The most common cause of miscarriage is sporadic chromosome errors. Chromosomal analysis of the miscarriage offers an explanation in at least 50% of cases. Conventional cytogenetic evaluation can only be done on fresh tissue, so it is critical that the treating physician consider genetic testing at the time of the miscarriage. Ultrasound can estimate the gestational age at the time of miscarriage and identify major abnormalities in some embryos. A careful pathological examination can add to the evaluation by ruling out rare disorders with the highest recurrence risk. A multidisciplinary approach to miscarriage evaluation is essential to understanding the cause and risk of recurrence. A thorough evaluation of a miscarriage, in combination with emotional support, can often provide the necessary reassurance and confidence as the patient prepares for her next pregnancy.
Miscarriage is defined as the loss of a pregnancy before viability. Although it can occur at any gestational age, most miscarriages occur in the first trimester. Even within the first trimester, miscarriage is less frequent with increasing gestational age. Patients experiencing a miscarriage can benefit from understanding the cause, and it often helps with the grieving process and planning for future pregnancies. Therefore, when a miscarriage occurs, evaluation for cause and risk factors is warranted. Although most pregnancy losses in the first trimester are due to sporadic chromosomal errors derived from the fertilized oocyte, documenting gestational age, anomalies, histological abnormalities, and genetic factors assists in providing prognostic information for future pregnancies. This review describes the essential components for the evaluation of first trimester miscarriage.
Women are diagnosed with a miscarriage in one of two ways, either based on human chorionic gonadotropin (hCG) testing or by ultrasound. A diagnosis of a biochemical pregnancy loss consists of a positive serum or urinary pregnancy test, usually combined with a delayed period. At some point before her first physician visit, she has bleeding and passage of tissue and the pregnancy test becomes negative. In this case, it is difficult to document the cause of miscarriage, but the clinical history and/or hCG results can provide some information about gestational age.
Fortunately, most women have access to early pregnancy care and often seek medical attention before passing miscarriage tissue. Whenever possible, failing pregnancies should be evaluated with ultrasound, quantitative hCG measurements, histopathology, and cytogenetics. A thorough evaluation often provides an explanation for the miscarriage and individualized prognostic information.
Semin Reprod Med. 2011;29(6):463-469. © 2011 Thieme Medical Publishers