Fetal blood sampling in twin pregnancies.

Objective: To evaluate the role of fetal blood sampling for prenatal diagnosis in twin pregnancies.

Methods: This was a retrospective study of 84 twin pregnancies that had undergone fetal blood sampling between the years 1977 and 2000. These results were compared with those from a similar study on amniocentesis and chorionic villus sampling.

Results: Miscarriage occurred in 3.6% of cases after fetal blood sampling. The total fetal loss rate was 13.6% and the fetal loss that could be attributed to the procedure was 8.2%. The procedure-related fetal loss rate was dependent on the indication for fetal blood sampling. The rates of preterm delivery at 28 weeks and neonatal mortality were 16.9%, 28.3%, 10.9%, 3.1% and 7.7%, respectively.

Conclusions: Fetal blood sampling in twin pregnancies carries higher risks for the fetus than do amniocentesis and chorionic villus sampling. However, it remains useful in evaluating the fetal condition in special circumstances such as hydrops and infection.