Environmental and Occupational Factors on Implantation Failure

It has been shown that reproductive activity is responsive to changes in the physical, psychosocial, and chemical environments. Occupational exposure has been identified to a wide range of putative hazards and adverse reproductive outcomes, or fertility. Such risks include the physical environment such as VDT and noise, as well as psychosocial stress and chemical agents. Some of these may have a direct or indirect effect on IVF outcomes. Psychosocial factors such as inadequate coping mechanisms, anxiety and/or depression are related to a lower incidence of IVF pregnancy. In this chapter the authors focus on the difficulties involved in linking exposure to putative hazardous substances to adverse reproductive outcomes in environmental and occupational settings, particularly the effectiveness of IVF procedures.

Impact of Climate Change on Animal Fertility

The fertility and reproductive efficiency of both male and female animals is very sensitive to climatic disturbances, particularly hyperthermia. The most evident consequences of heat stress are decreased quantity and quality of sperm production in males and compromised fertility in females. In this chapter, the effects of climate change on male and female reproduction have been separately and thoroughly elaborated. The effect of heat stress on embryo and fetal development has also been described. In the end, various approaches for mitigating the effects of heat stress on animals have been brought to light.

Effects on Fertility and Reproductive Behavior From Environmental Contaminants in Extreme Environments

Human infertility is increasing at an alarming rate and has affected nearly 12% of reproductive aged couples worldwide. Various reasons have been linked to its cause, besides the age of female partner, a huge number of environmental contaminants produced and used by humans throughout the world are one of the reasons for growing the infertility rate. Their exposure is virtually unavoidable. The literature review provides an overview regarding the effect of chemical agents on fertility. The environmental contaminants included in this review are plastics, pesticides, phthalates, metals, industrial chemicals, endocrine disrupters, and nano materials. The goal is to discuss the association between environmental contaminants and reproductive disorders with particular emphasis on infertility.

Thermotolerance for Physiological and Endocrine Regulation of Embryo-Uterine Development

Hyperthermia affects most aspects of reproductive performance in mammals by compromising the physiology of reproductive tract, through hormonal imbalance, disrupting the development and maturation of oocyte, causing embryonic mortality, abortion, growth retardation, and major developmental defects. Heat stress reduces the steroidogenic capacity of its theca and granulosa cells by altering the efficiency of follicular selection resulting in drop of luteinizing hormone and estradiol secretions from the dominant follicle in the plasma, reduced intensity, and duration of estrus expression. The mechanism for the developmental stage-dependent change in heat tolerance is considered to be the accumulation of antioxidants in embryos in response to heat-inducible production of reactive oxygen species. Morula or blastocysts can repair heat-induced misfolded or unfolded proteins or facilitate DNA damage induced apoptosis. Therefore, embryo transfer (ET) that can bypass the heat-sensitive stage could be a good solution to improve the conception rate under heat stress. However, further research is required to improve the reduction in pregnancy rates due to summer heat stress.

Climate Change and Its Impact on Soil Fertility and Life Forms

Climate change can disturb the characteristics of the soil either indirectly, or directly, or both. The direct effects include changes in the soil properties and composition by organic carbon transformation, precipitation, temperature, and % of moisture. The indirect impact includes nutrient cycling, improved soil erosion rate due to an increase in rate and intensity of rainfall, irrigation facility, changes in the crop rotation, and spadework practices. The presence of soil organic carbon (SOC) greatly influenced by the climatic condition. The crop cultivation depends upon the exchange of carbon between the troposphere and soil, which also vastly influences the fertility of the soil. The use, development, and management of soil depend upon soil structure, soil texture, soil stability, water holding capacity of the soil, availability of the nutrients, and erosion of the soil. Hence, deterioration of soil fertility by climatic change may affect the several soil lifeforms like fauna and flora either directly, or indirectly through nutritional value of the soil.

Impact of Heat Stress and Nutritional Stress on Early Embryo Development

The nutritional, physiological, and reproductive function has detrimental effects on heat stress, which is found in many species of mammals. High ambient temperature in mammals cause a decrease in the length and intensity of estrus by disturbing ovarian function as well as decreasing pregnancy rate after artificial insemination. The effects of nutritional stress on developing oocytes in the ovarian follicle and in the reproductive tract on early embryos are because of the environment where a breeding female lives before conception and at the early stages of pregnancy. Maturity of oocyte, blastocyst yield, prenatal survival, and the number of offspring born alive are affected by change in consumption and quantity of the food taken during the pre-mating period. To improve reproductive efficiency and offspring quality, it is necessary to detect and evaluate the deteriorating effects of heat stress on reproductive organs and cells and to plan nutrition related strategies.

Impact of Heat Stress on Embryonic Implantation

One of the expected effects of mammalian developmental defects is a rise in air temperature. Heat stress adversely affects embryo oogenesis, oocyte maturation, fertilization, and implantation. The number of defects caused by heat stress in all mammals is almost identical, but each species has its own particular sensitivity to specific defects. It suggests that genotype may have a significant effect on the type of defect, its occurrence, and its extent. By heat output and loss, the body temperature is usually preserved in a restricted range, but the equilibrium can be disrupted by illness, inadequate nutrition, and severe environmental temperature. Elevated maternal temperature during pregnancy, either by fever or any other means of heating, may result in embryo death, retarded development, abortion, and many embryonic defects such as cell proliferation, migration, differentiation and apoptosis or programmed cell death, structural and functional defects, and changes in maternal physiology. Maternal heat stress also reduces the levels of placental hormones. This chapter deals with the heat stress effect on reduction of reproductive function, implantation defects, etc. of different animals and humans.

Chronodisruption and Loss of Female Reproductive Potential Due to Shift Work

Entrainment of 24 hrs light/dark cycle is nowadays getting altered in corporate sector and even at home due to over exposure to artificial light at night (ALAN) and is commonly denoted as chronodisruption. Chronodisruption interferes with the daily physiology that is regulated by SCN/pineal-melatonin/Hypothalamo-Pituitary axis. In females, reduction in sleep due to shift work desynchronizes HPG-HPA axis induces a stress like condition, accompanied by increased free radical generation in ovary leading to polycystic ovaries, depletion of ovarian reserve, luteal phase defects, endometriosis, implantation failure, etc. Evidence suggest that there is remedial rescue by management of circulatory melatonin due to its chronobiotic/antioxidant/anti-inflamatory/antiapoptotic potentials and its role in ovarian folliculogenesis and steroidogenesis. Advancement in melatonin research suggests that it could be beneficial for commercial use, that is, (1) as an endogenous synchronizer, (2) to improve the quality of oocyte, and (3) for promoting success in the frequency of IVF.

Multidimensional Impact of Climate Change on Human Reproduction and Fertility

Research has identified a multidimensional, interactive relationship between climate change variables and an adverse (mostly) impact on the mammalian reproductive systems, reproductive organs, and fertility in animals, but direct evidence establishing the impact of climate change on reproductive health and fertility in humans is limited. Climate change has established direct or indirect linkages with re-emergence, geospatial redistribution of pathogens of likely reproductive health significance in humans. Similarly, alterations in growth, mortality rate, reproduction, and spatiotemporal distribution of vectors (e.g., zika virus – Aedes aegypti) and intermediate hosts (e.g., Schistosomiasis – snail) of certain infectious diseases of reproductive health importance are influenced by climate change variables like temperature, precipitation, and humidity. The exposure channels or effect pathways, through which the regional and global climate change can directly or indirectly influence the human reproductive ability, health, fertility, progeny, and thus, ultimately, demography can broadly be classified as physical variables, chemical hazards, biological agents, factors related to psycho-socio-behavior, and economy. The chapter is an overall account of how each of these factors, as an inherent component of climate change has the potential to cause a variable degree of impact on human reproduction from a medical point of view. As human reproductive systems are highly vulnerable to diseases and other post-catastrophic effects of extreme climate change events, so it is high time to understand the adversity and resort to proper and sustainable control measures for a healthy reproductive life of future generations.

Textile Industry and Health Hazards: Impact of Climate Change Issues and Fertility Potential

Textile industry is one of the primarily concerned industries in the world generating huge revenues where both the skilled and unskilled labours are employed. Raw materials are mainly synthetic chemicals rather than the natural one. Several bleaching agents, additives are also used to get sufficiently high and uniform degree of whiteness in the textile materials. Environmental contamination is also common by the textile effluents. All these substances are mutagenic and carcinogenic, and cause enormous health hazards to humans, animals, and aquatic lives. Infertility, implantation failure, and miscarriage due to exposure to dyes, dye intermediates, and other raw materials are major concern worldwide as integrity of both the male and female gametes are massively affected by them. However, little or no attention has been paid in real life scenario, mainly in the developing and under developed countries including adaptation of successful and advanced mitigation strategies. Therefore, the chapter highlights the common issues and possible remedial measures of the textile industry exposure with respect to fertility potential and pregnancy outcome.