Obstetrics & Gynecology>>>>>Preconception Counseling, Genetics, and Prenatal Diagnosis
Question 2#

A 24-year-old woman presents with a history of one first-trimester spontaneous abortion.

Which of the following is the single most common specific chromosome abnormality associated with first trimester miscarriage?

a. 45 X (Turner syndrome)
b. Trisomy 21 (Down syndrome)
c. Trisomy 18
d. Trisomy 16
e. 46 XXY (Klinefelter syndrome)

Correct Answer is A


Chromosomal abnormalities are found in approximately 50% of spontaneous abortions in the first trimester. Chromosome abnormalities become less common in advancing pregnancy, and are found in approximately one-third of second trimester losses and 5% of third trimester losses. Autosomal trisomy is the most common group of chromosomal anomalies leading to first trimester miscarriage. However, 45 X (Turner syndrome) is the most common single abnormality found.