A recent US study comparing different drugs for ovarian stimulation in women with unexplained infertility demonstrates that letrozole is less effective than gonadotropins or clomiphene; however, the primary end point for the study was not efficacy but, rather, multiple pregnancy rates. This study confirms, yet again, that gonadotropins are associated with unacceptably high rates of multiple births.
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References
Legro, R. S. et al. Letrozole or clomiphene for infertility in the polycystic ovary syndrome. N. Engl. J. Med. 371, 146–1464 (2014).
Fauser, B. C. Revisiting ovulation induction in PCOS. Nat. Rev. Endocrinol. 10, 704–705 (2014).
Diamond, M. P. et al. Letrozole, gonadotropins, or clomiphene for unexplained infertility. N. Engl. J. Med. 373, 1230–1240 (2015).
Fauser, B. C. in Yen & Jaffe's Reproductive Endocrinology (eds Strauss, J. F. & Barbieri, R. L) 701–733 (Elsevier, 2014).
Fauser, B. C. & Macklon, N. S. Multiple birth resulting from ovarian stimulation for subfertility treatment. Lancet 365, 1807–1816 (2005).
Bensdorp, A. J. et al. Prevention of multiple pregnancies in couples with unexplained or mild male subfertility: randomised controlled trial of in vitro fertilisation with single embryo transfer or in vitro fertilisation in modified natural cycle compared with intrauterine insemination with controlled ovarian hyperstimulation. BMJ 350, g7771 (2015).
Evers, J. L. Female subfertility. Lancet 360, 151–159 (2002).
Kamphuis, E. I., Bhattacharya, S., van der Veen, F., Mol, B. W. & Templeton, A. Are we overusing IVF? BMJ 348, g252 (2014).
Steures, P. et al. Intrauterine insemination with controlled ovarian hyperstimulation versus expectant management for couples with unexplained subfertility and an intermediate prognosis: a randomised clinical trial. Lancet 368, 216–221 (2006).
Reindollar, R. H. et al. Randomized clinical trial to evaluate optimal treatment for unexplained infertility: the fast track and standard treatment trial. Fertil. Steril. 94, 888–899 (2010).
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B.C.J.M.F. has received fees and grant support from COGI, Euroscreen, Ferring, Gedeon Richter, Finox, GenOvum, Nederlandse Hartstichting, NGI, Merck Serono, Pantarhei Bioscience, Preglem, Watson Laboratories and ZonMW.
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Fauser, B. Unexplained infertility — ongoing transatlantic debate. Nat Rev Endocrinol 12, 8–10 (2016). https://doi.org/10.1038/nrendo.2015.200
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DOI: https://doi.org/10.1038/nrendo.2015.200
