Fetal blood sampling and its complications related to the indications for fetal blood sampling.

A prospective study on fetal blood sampling (FBS) was conducted in the Fetomaternal Medicine Division of the Department of Obstetrics and Gynaecology at the National University Hospital, Singapore. FBS was performed on 159 occasions in 156 women between January, 1988 and December, 1991. The aim of this study was to identify the factors that were associated with an adverse outcome following the procedure. Twenty four abnormal pregnancies were terminated; of the remaining 132 desired pregnancies the overall pregnancy loss was 44 (33.3%), which included those within 2 weeks and those after 2 weeks of the procedure and neonatal deaths. Fetal loss occurring within 2 weeks of the procedure is considered a procedure-related loss which occurred in 19 (14.3%) of the 132 pregnancies. When the fetal loss occurred within 2 weeks of the procedure 89% had a major abnormality on ultrasonographic scanning. The conclusion from our study is that the risks of FBS were increased in abnormal pregnancies, most likely due to the underlying pathology.