REVIEW PAPER Impact of high altitude on key determinants of female reproductive health: a review Snigdha Shaw 1 & Dishari Ghosh 1 & Utkarsha Kumar 1 & Usha Panjwani 1 & Bhuvnesh Kumar 1 Received: 26 March 2018 /Revised: 24 August 2018 /Accepted: 27 August 2018 # ISB 2018 Abstract Imperishable research work was done on females visiting high-altitude (HA) areas for recreational activities or job purposes as well as on female HA natives. Hypoxia at HA is an unavoidable condition that affects the determinants of female reproductive functions like, the age of menarche and menopause, whole reproductive span, hormone synthesis, and fertility. This review will emphasize whether HA hypoxia is a threat to women: residents or visitors by analyzing these proximate determinants. Delayed menarcheal and advanced menopausal age was found to shorten the reproductive span in some HA populations, whereas in some cases, menstrual cycle was also reported to be irregular. In addition, the completed fertility rate (CFR) was increased when people migrated to lower altitude. Altered stress hormones and reproductive hormones were observed in sea-level females exposed to HA. Oxidative stress (OS) at HA was also reviewed to explain the probable reasons for the observed changes in these determi- nants because disturbed redox homeostasis may be a connecting link, affecting the reproductive functions. In conclusion, HA hypoxia plays a crucial role on various determinants of female reproductive health and this review will be helpful for more precise study along with the probable underlying mechanisms responsible for the changes in female reproductive functions at HA. Keywords High altitude . Hypoxia . Women . Reproductive health . Menarche . Menopause . Fertility . Oxidative stress Introduction Across the world more than 20 million people live above 3000 m (Liao et al. 2010). Numerous studies, both on males and females at high altitude (HA) claimed that hypoxia intrude into their reproductive function. Some authors believed hyp- oxia as a threat to the reproductive system, whereas some provided data, disagreeing to consider hypoxia as a major stressor. A considerable body of literature exists, documenting a decrease in male reproductive hormone in both animals as well as humans exposed to HA (Basu et al. 2000; Okumura et al. 2003; Sawhney et al. 1985). Disturbed spermatogenesis, sperm count, and motility (Cikutovic et al. 2009; Donayre et al. 1968; Gasco et al. 2003; Liao et al. 2010; Okumura et al. 2003) and decreased luteinizing hormone (LH) (Bangham and Hackett 1978) have been observed after exposure to HA hyp- oxia. On the contrary, an increase in testosterone and follicular-stimulating hormone (FSH) and LH (Coksevim et al. 2006), along with no change in testicular and semen vol- ume, sperm velocity or linearity (Okumura et al. 2003), testic- ular and seminal vesicle weight (Altland and Highman 1968), and fertility (Dutt 1980; Gonzales 2007; Vitzthum and Wiley 2003) has also been reported. In the case of females at HA, longer ovarian cycle (Escudero et al. 1996; Johnson et al. 1987), higher FSH (Gonzales and Gonez 2000) level that might trigger early menopause, as well as no significant change in hormonal level was also found (Vitzthum 2001; Vitzthum et al. 2000). Therefore, the available findings need to be gathered together to find the reasons behind these vari- ations and to understand the actual role of hypoxia. Nowadays, female residents of sea level are frequently vis- iting HA for recreational, trekking, and service purposes. Whether this residency period at altitude affects their normal physiology or has a residual effect on their reproductive life, after returning to sea level, is not clear due to scanty informa- tion. Here, we will present many studies done by renowned scientists across the world on HA female natives, migrants, and visitors and extract the probable effect of HA hypoxia on their reproductive health. We will also review the available data on menarcheal and menopausal age, time of ovulation, changes * Dishari Ghosh dghosh@dipas.drdo.in 1 High Altitude Physiology Department, Defence Institute of Physiology and Allied Sciences, Delhi, India International Journal of Biometeorology https://doi.org/10.1007/s00484-018-1609-0