Menstrual cycle is the regular process of changes that occur in a woman's body which prepares it for pregnancy. The cycle is controlled by hormones and typically lasts for 28 days. The cycle is divided into four phases: menstrual, proliferative, ovulatory and secretory. Among these phases, ovulation occurs during the proliferative phase.

Proliferative Phase
The proliferative phase is the second phase of the menstrual cycle and occurs after the menstrual phase. During this phase, the follicle-stimulating hormone (FSH) is released from the pituitary gland which triggers the growth and maturation of follicles in the ovary. These follicles contain eggs which will be released during ovulation. The follicles also produce estrogen which thickens the lining of the uterus in preparation for a potential pregnancy.

Ovulation
Ovulation is the process of releasing a mature egg from the ovary into the fallopian tube. It typically occurs around day 14 of a 28-day menstrual cycle but may vary from person to person. During ovulation, the surge in luteinizing hormone (LH) triggers the release of the mature egg from the follicle. The egg then travels through the fallopian tube towards the uterus, where it may be fertilized by sperm.

Conclusion
In conclusion, ovulation occurs during the proliferative phase of the menstrual cycle when a mature egg is released from the ovary into the fallopian tube. This phase is characterized by the growth and maturation of follicles in the ovary and the thickening of the uterine lining.