Microchimerism After Induced or Spontaneous Abortion

OBJECTIVE: To investigate fetomaternal microchimerism in women with induced abortion or spontaneous pregnancy loss. METHODS: Peripheral blood samples were obtained from 76 healthy women who underwent dilation and curettage in the first trimester but had never had an abortion or male delivery before. Samples were collected at three time points: just before, 7 days after, and 30 days after abortion. Y chromosome-specific, nested polymerase chain reaction targeting the sex-determining region of Y (SRY) was used to test DNA extracted from buffy coat cells. DNA was also extracted from the chorion to determine sex. The sensitivity of our assay allowed detection of approximately one male cell in 100,000 female cells. RESULTS: Thirty-six male and 40 female chorions were obtained. Male DNA was found in 52.8% of women who had a male chorion before abortion, decreasing to 5.6% at 7 days after abortion. At 30 days after abortion, no male DNA was detected. Male DNA was never detected at any point from women with a female chorion. CONCLUSION: Fetal cells in the maternal circulation are undetectable 30 days after induced abortion or spontaneous pregnancy loss. Fetal cells may be harbored in maternal organs.