The effect of seasonality on reproductive outcome of patients undergoing intracytoplasmic sperm injection: A descriptive cross-sectional study


Background: There is conflicting evidence regarding the impact of season on the assisted reproductive technology outcome.

Objective: To retrospectively compare three year outcome of women undergoing their first intracytoplasmic sperm injection cycle, across seasons.

Materials and Methods: In this descriptive cross-sectional study, 3,670 women who underwent their first intracytoplasmic sperm injection cycle in Mehr Medical Institute, Rasht, Iran between April 2010 and May 2014 were studied. Women were divided into four groups according to the day of oocyte retrival as: spring (n = 808), summer (n = 994), autumn (n = 1066), and winter (n = 802). Basal and stimulation charecteristics were compared among groups.

Results: While sperm concentration and motility were significantly lower during summer, the total number of retrieved and metaphase II oocytes were significantly higher (p = 0.0001, p = 0.0001, p = 0.004, p = 0.02, respectively). Fertilization rate were significantly higher during autumn (p = 0.0001). Also, the number of high- quality transferred embryos were significantly higher during summer and winter (p = 0.03). A similar pattern was observed in implantation rate and pregnancy over the four seasons

Conclusion: Despite the fact that intracytoplasmic sperm injection minimize the seasonal effect on pregnancy outcome, changes in pregnancy rate still occur among different seasons without particular pattern. It seems that performing assisted reproductive technology procedures in a particular season should be considered as an effective factor.

Key words: Intracytoplasmic sperm injection, Seasons, Pregnancy outcome.

[1] Nishiwaki-Ohkawa T, Yoshimura T. Molecular basis for regulating seasonal reproduction in vertebrates. Journal of Endocrinology 2016; 229: R117–R127.

[2] Dardente H, Wood S, Ebling F, Sáenz de Miera C. An integrative view of mammalian seasonal neuroendocrinology. Journal of Neuroendocrinology 2019; 31: e12729.

[3] Saalfeld ST, Lanctot RB. Multispecies comparisons of adaptability to climate change: A role for life−history characteristics? Ecology and Evolution 2017; 7: 10492– 10502.

[4] Cummings DR. Human birth seasonality and sunshine. Am J Hum Biol 2010; 22: 316–324.

[5] Santi D, Magnani E, Michelangeli M, Grassi R, Vecchi B, Pedroni G, et al. Seasonal variation of semen parameters correlates with environmental temperature and air pollution: A big data analysis over 6 years. Environ Pollut 2018; 235: 806–813.

[6] Tackenberg MC, McMahon DG. Photoperiodic programming of the SCN and its role in photoperiodic output. Neural Plasticity 2018; 2018: 1–9.

[7] Nakane Y, Yoshimura T. Photoperiodic regulation of reproduction in vertebrates. Annual Review of Animal Biosciences 2019; 7: 173–194.

[8] Revelli A, La Sala GB, Gennarelli G, Scatigna L, Racca C, Massobrio M. Seasonality and human in vitro fertilization outcome. Gynecol Endocrinol 2005; 21: 12–17.

[9] Wunder DM, Limoni C, Birkhauser MH, Swiss FIVNATGroup. Lack of seasonal variations in fertilization, pregnancy and implantation rates in women undergoing IVF. Hum Reprod 2005; 20: 3122–3129.

[10] Wood S, Quinn A, Troupe S, Kingsland C, Lewis-Jones I. Seasonal variation in assisted conception cycles and the influence of photoperiodism on outcome in in vitro fertilization cycles. Hum Fertil 2006; 9: 223–229.

[11] Braga DP, Setti A, Figueira Rde C, Iaconelli Jr A, Borges Jr E. Seasonal variability in the fertilization rate of women undergoing assisted reproduction treatments. Gynecol Endocrinol 2012; 28: 549–552.

[12] Gindes L, Yoeli R, Orvieto R, Shelef M, Ben−Rafael Z, Bar−Hava I. Pregnancy rate fluctuations during routine work in an assisted reproduction technology unit. Hum Reprod 2003; 18: 2485–2488.

[13] Liu X, Bai H, Mol BW, Shi W, Gao M, Shi J. Seasonal variability does not impact in vitro fertilization success. Sci Rep 2019; 9: 17185. 1–5.

[14] Xiao Y, Wang M, Liu K. The influence of seasonal variations on in vitro fertilization and fresh/frozen embryo transfer: a retrospective study. Arch Gynecol Obstet 2018; 298: 649– 654.

[15] Mills J, Kuohung W. Impact of circadian rhythms on female reproduction and infertility treatment success. Curr Opin Endocrinol Diabetes Obes 2019; 26: 317–321.

[16] Rojansky N, Benshushan A, Meirsdorf S, Lewin A, Laufer N, Safran A. Seasonal variability in fertilization and embryo quality rates in women undergoing IVF. Fertil Steril 2000; 74: 476–481.

[17] Cos S, Sánchez-Barceló EJ. Melatonin and mammary pathological growth. Front Neuroendocrinol 2000; 21: 133–170.

[18] Rojansky N, Brzezinski A, Schenker JG. Seasonality in human reproduction: an update. Hum Reprod 1992; 7: 735–745.

[19] Yucel C, Kozacioglu Z. Effect of seasonal variation on the success of micro−dissection testicular sperm extraction: A pilot study. Andrologia 2019; 51: e13156.

[20] Centola GM, Eberly S. Seasonal variations and agerelated changes in human sperm count, motility, motion parameters, morphology, and white blood cell concentration. Fertil Steril 1999; 72: 803–808.

[21] Reinberg A, Smolensky MH, Hallek M, Smith KD, Steinberger E. Annual variation in semen characteristics and plasma hormone levels in men undergoing vasectomy. Fertil Steril 1988; 49: 309–315.

[22] Rao M, Xia W, Yang J, Hu LX, Hu SF, Lei H, et al. Transient scrotal hyperthermia affects human sperm DNA integrity, sperm apoptosis, and sperm protein expression. Andrology 2016; 4: 1054–1063.

[23] Abdelhamid MHM, Walschaerts M, Ahmad G, Mieusset R, Bujan L, Hamdi S. Mild experimental increase in testis and epididymis temperature in men: effects on sperm morphology according to spermatogenesis stages. Transl Androl Urol 2019; 8: 651–665.