RESUMEN
To our knowledge, this is the first analysis in which male and female weights have been combined. The registry dataset covering a 12-year period was analysed for all treatment cycles where an embryo transfer was reported. In all, 706,360 cycles were analysed. Treatments include IVF, ICSI, IVF/ICSI and CPE. The highest success rate in IVF cycles was found in couples, with an obese male partner. In the group of obese women, the pregnancy rate decreased to 27.2%. Similar to IVF treatment, the highest success rate in ICSI cycles was found in couples, where either the male or the female partner was obese. The highest success rate in cycles with a cryopreserved embryo transfer was observed in couples where both partner were obese. The lowest success rate was seen where the female partner was obese. Our data analysis suggests that the combination of an obese male and a normal-weight female is positively related to better implantation rates in IVF as well as ICSI-cycles. This combination is more likely to be found in couples with a higher social status. Therefore, the increased pregnancy rate in this group might as well be related to other lifestyle factors associated with higher social status.