An Exploratory Study to Investigate the Effect of FE 999302 When Given Together With Follitropin Delta at Different Time Intervals During Controlled Ovarian Stimulation.

Inclusion Criteria: 1. Subject informed consent form signed before any trial-related activities. 2. In good physical and mental health as judged by the investigator. 3. Serum anti-Müllerian hormone (AMH) levels of \>35.0 pmol/L at screening (measured at central laboratory). 4. Pre-menopausal women between the ages of 18 and 40 years. The subjects must be at least 18 years (including the 18th birthday) and no more than 40 years (up to the day before the 41st birthday) when they sign the informed consent(s). 5. Infertile women diagnosed with tubal infertility, unexplained infertility, endometriosis stage I/II or with partners diagnosed with male factor infertility, eligible for in vitro fertilisation (IVF) and/or intracytoplasmic sperm injection (ICSI) using fresh or frozen ejaculated sperm from male partner or sperm donor. 6. Infertility for at least 1 year before screening for subjects \<35 years or for at least 6 months for subjects ≥35 years (not applicable in case of tubal or severe male factor infertility). 7. No more than two controlled ovarian stimulation cycles initiated, regardless of outcome (taking exclusion criteria 2 and 3 into account) and the subject must be suitable for treatment with 10 or 15 µg/day follitropin delta (corresponding to 150 or 225 IU). 8. Regular menstrual cycles of 24-35 days (both inclusive), presumed to be ovulatory. 9. Early follicular phase (cycle day 2-5) serum levels of follicle-stimulating hormone (FSH) between 1 and 15 IU/L (measured at central laboratory). 10. Body mass index (BMI) between 18.0 and 32.0 kg/m2 (both inclusive) at screening. Exclusion Criteria: 1. Known polycystic ovary syndrome (PCOS) or known endometriosis stage III-IV (American Society for Reproductive Medicine, 2012). 2. Poor response in a previous controlled ovarian stimulation cycle using a gonadotropin starting dose of 150 IU/day (corresponding to 10 µg follitropin delta) or higher. Poor response is defined as \<4 oocytes retrieved, or cycle cancellation before oocyte retrieval due to inadequate follicular development. 3. Severe ovarian hyperstimulation syndrome (OHSS; grade 4 or 5) in a previous controlled ovarian stimulation cycle, as judged by the investigator. 4. One or more follicles ≥10 mm (including cysts) observed on the transvaginal ultrasound before randomisation on stimulation day 1 (puncture of cysts is allowed before randomisation). 5. Any known clinically significant systemic disease (e.g. insulin-dependent diabetes). 6. Any known endocrine or metabolic abnormalities (pituitary, adrenal, pancreas, liver, or kidney) with the exception of controlled thyroid function disease. 7. Known tumours of the ovary, breast, uterus, adrenal gland, pituitary, or hypothalamus which would contraindicate the use of gonadotropins. 8. Any abnormal finding of clinical chemistry and haematology at screening or vital signs at randomisation, which is judged clinically relevant by the investigator and/or requires intervention. 9. Currently breast-feeding. 10. Undiagnosed vaginal bleeding. 11. Findings at the gynaecological examination at screening which preclude gonadotropin stimulation or are associated with a reduced chance of pregnancy, e.g. congenital uterine abnormalities or retained intrauterine device. 12. Pregnancy (negative urinary pregnancy tests must be documented at screening and before randomisation) or contraindication to pregnancy. 13. Use of fertility modifiers during the last menstrual cycle before screening, including dehydroepiandrosterone (DHEA) and metformin or cycle programming with oral contraceptives, progestogen, or estrogen preparations.