First trimester fetal heart rate: response to chorionic villus sampling in the chromosomally normal fetus.

The objective of this prospective study was to evaluate the fetal heart rate before and after the procedure and whether this had any effect on the risk of pregnancy loss following chorionic villus sampling (CVS) and chromosomally normal pregnancies. Four hundred and seventeen pregnancies were evaluated. The heart rate before the procedure was similar for both male and female fetuses. Significant procedure-related changes in fetal heart rate occurred only with male fetuses undergoing the transabdominal CVS technique. Fetal heart rate decelerations following CVS were more common than accelerations. Fetal heart rate changes following CVS were not able to predict the pregnancies ending in spontaneous abortion. Transabdominal CVS had a lower loss rate after the procedure, compared to the transcervical technique (p = 0.0001). Small-for-date fetuses had a higher loss rate after the procedure compared to normal-sized fetuses (p = 0.001).