Reproductive Biology and Endocrinology volume 16, Article number: 22 (2018)
Lifestyle and infertility
Recently, great interest has been focused on several lifestyle factors including the emotional state, typical of stress or anxiety condition, modifiable habits, and ways of life that can greatly influence overall health and well-being. Below are listed several of those factors for which there is defined evidence of a negative impact on fertility.
- Psychological stress for social life and work– Particularly in Western countries there is a larger incidence of depression and anxiety, which is partially related to the lifestyle and a number of stressful jobs. Thus, the symptoms related to both depression and anxiety have been reported as more prominent in infertile than in fertile women. In a series of studies, it has been indeed described that infertile women are more likely to experience higher levels of psychological distress, as well as high levels of reactive depression, and increased likelihood of anxiety. A probability-based study also suggested that the general distress levels are lower in the presence of higher socioeconomic status, or conversely, higher in the presence of highly stressful jobs, poor economic conditions, or missing work. These aspects concur to generate a persistent condition of psychological stress in addition to detrimental well-being feelings, which may alter the physiologic maturation of oocytes.
- Smoking– Although in the absence of defined molecular mechanisms, there is a negative influence of smoking resulting in reduced fertility in female smokers. Several effects on negative reproductive consequences of chronic smoking include rapid depletion of ovarian follicles, conception delay, increased risk of spontaneous miscarriage in both natural and assisted conception cycles as well as increased risk of birth defects.
- Drugs, caffeine, and alcohol– There are several daily or occasionally assumed drugs that are known to impact fertility. Non-steroidal anti-inflammatory drugs, commonly used to treat pain or inflammation are defined as ovulation inhibitors whereas cytotoxic chemotherapy drugs used in anticancer treatments are primarily responsible for ovarian failure in women. On the other hand, the higher introduction of caffeine has been associated with an increased risk of pregnancy loss whereas in alcohol abusers the liver metabolic alterations and/or psychoneurological damages concur with stress factors to restrain the oocyte maturation.
- Diet and variations of body weight– Inadequate diets as those with poor calories and protein content or, vice versa, based on habitual hypercaloric food assumptions, leading to severe thinness or overweight, definitely affect ovarian function and increase the risk of women infertility. In this regard, it has been reported that the time to conceive is longer in women with a BMI over 25 kg/m2 or, vice versa, less than 19 kg/m2, and that obesity and overweight are significantly associated with decreased pregnancy rates, increased requirements for gonadotrophins and higher miscarriage events. High BMI is also associated with adverse pregnancy outcomes such as gestational diabetes, hypertension, and premature labor.
Evidence on the effect of diet composition on fertility is scarce. Several studies investigating the effect of various dietary factors on fertility have been completed on data from extended studies including 116,678 women in the Nurses’ Health Study II. In these reports, it has been described as a reduced risk of fertility due to ovulatory disorder in women whose diet included prevalently foods with low glycaemic content and limited intake of nutrients. This dietary restriction, indeed, may increase insulin resistance, such as lower trans fatty acid intake thus supporting the pivotal role exerted by the glucose homeostasis and insulin sensitivity in the normal ovulatory function and fertility as occurs in women with normal weight.
- Physical activity– The excess in physical activity could be closely linked to considerable negative effects on the whole body including skeletal pathologies or functional derangements in endocrine, cardiovascular, reproductive, and central nervous systems. In contrast with the vantages of sports activities in decreasing abdominal fat, blood glucose, lipids, and insulin resistance as well as in regulating menstrual cyclicity, ovulation, and fertility due to the lowered testosterone levels and increase of sex hormone binding globulin (SHBG), the intensively exerted agonistic sports may typically produce the ‘female athlete triad’, a syndrome characterized by amenorrhea, osteoporosis and eating disorder as defined by the American College of Sports Medicine.
- Environmental pollutants– Based on several investigative studies, the OSHA (Occupational Safety and Health Administration, USA) provided evidence that chronic exposure to specific chemicals such as organic solvents, aromatic amines, heavy metals, phytodrugs, vegetal toxins, and others is associated with reduced fertility as well as to increased tendency to either occasional or recurrent abortions. The pathogenic mechanisms leading to unsuccessful fertility by these conditions are unclear and further studies are required to clarify the effect of environmental pollutants on female fertility.
The growing interest and the amount of research in this field emphasize the role of lifestyle factors in affecting the woman’s fertility and particularly obesity may represent a major condition in which both alterations of metabolic pathways and inflammatory factors concur to reduce the oocyte viability leading to subfertility or infertility.
Read the full article:
https://rbej.biomedcentral.com/articles/10.1186/s12958-018-0336-z
