However, although effective, the pregnancy rate in the largest study conducted was 4.6 per 100 woman-years, which is too high of a failure rate for the medication to be recommended as a safe method of birth control.
haʊˈɛvɚ, ɔːlðˈoʊ ɪfˈɛktɪv, ðə pɹˈɛɡnənsi ɹˈeɪt ɪnðə lˈɑːɹdʒɪst stˈʌdi kəndˈʌktᵻd wʌz fˈoːɹ.sˈɪks pɜː wˈʌnhˈʌndɹɪd wˈʊmənjˈɪɹz, wˌɪtʃ ɪz tˈuː hˈaɪ əvə fˈeɪlɪɹ ɹˈeɪt fɚðə mˌɛdɪkˈeɪʃən təbi ɹˌɛkəmˈɛndᵻd æz ɐ sˈeɪf mˈɛθəd ʌv bˈɜːθ kəntɹˈoʊl.