Comparison of IVF cycles reported in a voluntary ART registry with a mandatory registry in Spain

Monitoring assisted reproductive technology (ART) is essential to evaluate the performance of fertility treatment and its impact on birth rates. In Europe, there are two kinds of ART registers: voluntary and mandatory. The validity of register data is very important with respect to the quality of register-based observational studies. The aim of this paper is to determine the degree of agreement between voluntary and mandatory ART registers.

The two sources for the data compared in this study (referring to 2005 and 2006) were FIVCAT.NET (an official compulsory Assisted Reproduction Registry within the Health Ministry of the Regional Government of Catalonia, to which all authorized clinics, both public and private, performing assisted reproduction in the region are obliged to report) and the register of the Spanish Fertility Society (SEF), to which data are provided on a voluntary basis. The SEF register data were divided into two groups: (i) data from clinics in Catalonia (SEF-CAT); (ii) data from the rest of Spain, excluding Catalonia (SEF-wCAT). The techniques compared were IVF cycle using patients' own eggs (IVF cycle) versus donor egg cycles.

For IVF cycles, the voluntary ART register reflected 77.2% of those on the official one, but the corresponding figure was only 34.4% with respect to donated eggs. The variables analysed in the IVF cycle (insemination technique used, patients' age, number of embryos transferred, pregnancy rates, multiple pregnancies and deliveries) were similar in the three groups studied. However, we observed significant differences in donor egg cycles with regard to the insemination technique used, pregnancy rates and multiple pregnancies between the voluntary and the official register.

Data from the voluntary ART register for IVF cycles are valid, but those for donor egg cycles are not. Further study is necessary to determine the reasons for this difference.