Ovarian stimulation is an integral part of in vitro fertilization (IVF) treatment and plays a key role in the method's efficiency. It is a complex modality of IVF treatment that is often experienced as stressful by patients, as it usually involves daily self-injection of follicle-stimulating hormone (FSH). The recently developed FSH-CTP (corifollitropin alpha) is a recombinant, long-acting derivative of the FSH molecule. It consists of the α-subunit of human FSH and a hybridized subunit made up of the carboxy terminal peptide (CTP) of the β-subunit of human chorionic gonadotropin (hCG) and the FSH β-subunit. Phase III data show that the effect of FSH-CTP lasts for several days and is similar in terms of effectiveness and safety to daily FSH administration as part of ovarian stimulation in IVF treatment. It can therefore considerably reduce the number of self-injections required for stimulation and hence lower the stress of treatment for patients. This may increase acceptance among patients undergoing controlled ovarian stimulation.