Secondary oocyte will complete meiosis when a sperm cell penetrates the oocyte membrane (fertilization).
The oocyte (is arrested at an early stage of the first meiotic division as a primary oocyte. During each menstrual cycle, one the day before ovulation gonadotropin hormone (luteinizing hormone) stimulates completion of meiosis 1. After the meiosis 1, 2 haploid daughter cells are formed: one becomes the secondary oocyte the other forms the first polar body. Newly formed secondary oocyte starts meiosis 2 which arrests at metaphase which will continue after the fertilization.