follicular phase; proliferative phase
Medical term for the phase of the menstrual or estrous cycle when ovarian follicles mature, before ovulation.
Estrogen secretion increases during the follicular phase.
黄体期 is the luteal phase, occurring after ovulation and contrasting with the follicular phase.
Compound of 卵胞 (らんぽう, 'ovarian follicle') and 期 (き, 'period, phase').