Because of the higher yield over traditional chromosomal analysis, chromosomal microarray analysis (CMA) is being used increasingly in prenatal diagnosis. Unfortunately, the clinical implication of many copy number variants found on prenatal CMA is uncertain, complicating genetic counseling. Recognizing that uncertain results will be encountered frequently as more of the genome is assayed prenatally, we set out to understand the experiences and needs of genetic counselors when counseling patients about uncertain prenatal microarray results, their comfort with various aspects of prenatal genetic counseling, and their interest in additional education and training about prenatal microarray testing. We first interviewed 10 genetic counselors about their experiences of providing pre- and post-test genetic counseling about prenatal CMA. Based on the findings from the counselor interviews, we developed items for a survey to assess the prevalence of genetic counselors' attitudes towards, experience and comfort with, and educational needs regarding prenatal CMA. Based on surveys completed by 193 prenatal genetic counselors, we found that when there is an uncertain CMA result, only 59% would be comfortable providing genetic counseling and only 43% would be comfortable helping a patient make a decision about pregnancy termination. Being less comfortable was associated with seeing fewer patients having prenatal CMA testing. Respondents expressed a high degree of interest in additional education about prenatal CMA and counseling about uncertain results. Further genetic counselor education and training aimed at improving counselors' personal comfort with uncertain results and communicating about them with patients is needed.