Fever in women may interfere with follicular development during controlled ovarian stimulation

Purpose: This study aims to evaluate the effects of fever on follicular development in women undergoing controlled ovarian stimulation during in vitro fertilisation (IVF) and intracytoplasmic sperm injection (ICSI) cycles. Materials and methods: This was a retrospective observational self-controlled study at a tertiary-care fertility centre. Six gonadotropin stimulation cycles characterised by poor ovarian response in which women reported the occurrence of a febrile illness, were considered for evaluation. Fever-exposed cycles were compared to the next stimulation cycle in the same women. Primary outcome measures were final number of pre-ovulatory follicles (>= 16mm) and final peak serum estradiol levels (pg/mL). Other outcome measures were final number of medium-sized follicles (12-15 mm), final mean estradiol serum level per follicle >= 12mm (pg/mL), total days of stimulation and total gonadotropin ampoules utilised. Results: Fever-exposed cycles were associated with significantly lower number of pre-ovulatory follicles (0.7 +/- 0.8), significantly higher number of medium-size follicles (21.0 +/- 4.5), and significantly reduced serum estradiol per follicle >= 12mm (50.7 +/- 11.7 pg/mL). They also required a significantly longer duration of ovarian stimulation (15.7 +/- 3.3 days) and a significantly increased number of gonadotropin ampoules (47.2 +/- 10.9). Four women had polycystic ovary syndrome and one hypothalamic hypogonadism. Conclusion: This preliminary report suggests a possible negative effect of fever on follicular development and ovarian estradiol production in some women undergoing controlled ovarian stimulation.