Recombinant luteinizing hormone (rLH) in addition to FSH probably increases pregnancy rates, but it is not certain if the live birth rate is also increased. Using low dose human chorionic gonadotropin (hCG) to replace FSH during the late follicular phase in women undergoing hyperstimulation as part of IVF may make little or no difference to pregnancy rates, and possibly leads to in an equivalent number of oocytes retrieved, but with less expenditure of FSH. Before ovarian stimulation with antagonist protocols, pretreatment with combined oral contraceptive pills probably reduces the rate of live birth or ongoing pregnancy, while it is uncertain whether pretreatment with progesterone only has any effect on live birth or ongoing pregnancy rates. For other stimulation protocols, the evidence around pretreatment with combined oral contraceptives and progesterone only is uncertain.