RESUMO
PURPOSE: A recent publication by Swedish Colleagues in Fertility & Sterility for the first time, statistically correctly, attempted to assess risks of twin IVF pregnancies in comparison to two consecutive singleton IVF pregnancies. Historic comparisons have been statistically incorrect, comparing risks of one twin to one singleton pregnancy. We here analyze data and conclusions presented in this Swedish study. METHODS: We reviewed the manuscript by Sazonova et al. (Fertil Steril, 2013) (doi: 10.1016/j.fertnstert.2012.11.023 ). RESULTS: Based on incorrect statistical methodology, twins after in vitro fertilization (IVF) have come under attack as "adverse" outcomes. Above noted study recently, for the first time, correctly compared one twin to two consecutive singleton pregnancies. Investigators, however, in our opinion interpreted their own data incorrectly by claiming "dramatically" higher maternal and neonatal risks in twin pregnancies. Our interpretation of reported data, indeed, in contrast suggests surprisingly minor differences in observed twin-risks. Moreover, such minor risk increases do not offer adequate compensatory benefits for significantly lower pregnancy chances in first IVF cycles with eSET in comparison to two-embryo transfers (2-ET). CONCLUSIONS: As significantly higher maternal and neonatal risks of twin IVF pregnancies represent the principal rationale for eSET, the Swedish study actually suggests that eSET offers neither patient-friendly nor cost-effective treatment options for IVF, except where patients object to twins or have medical contraindications. The need for a second pregnancy to achieve equal outcome (2 children), resulting treatment delays, increased efforts and costs, in absence of any guarantees that a second successful singleton pregnancy/delivery will ever be accomplished, invalidates eSET as a routine procedure.