Feto-maternal transfusion after chorionic villus sampling. Evaluation by maternal serum alphafetoprotein measurement.

The alphafetoprotein (AFP) concentration in maternal serum was determined before and after chorionic villus sampling (CVS). A significant increase of 20% or more in the pre-CVS level was noted immediately after sampling in 59% of 837 pregnancies indicating some degree of feto-maternal haemorrhage. The increase in the AFP concentration in maternal serum was correlated with the weight of the tissue sample but not with the number of sampling attempts. A correlation of AFP increase and frequency of spontaneous abortions following CVS was suggested only in the group with an AFP increase of more than 100% or with a continuing rise in the first hour following CVS. CVS in early pregnancy obviously did not interfere with maternal serum AFP screening for neural tube defects in the second trimester. Although AFP measurement before and after CVS seems to have no immediate diagnostic application, in the research phase of CVS it may help to identify those procedures that are the least traumatic.