Complex sentence: Progestin is present in the combined oral contraceptive pill and the hormonal intrauterine device, reduces risk the of endometrial cancer by 30-50% over 10--20 years.
Split into simpler sentences: Progestin is present in the combined oral contraceptive pill and the hormonal intrauterine device (IUD). Progestin reduces risk of endometrial cancer by 30-50% over 10--20 years.