From the Guidelines
Overlooked causes of infertility include age, obesity, poor diet, smoking, anabolic steroid use, stress, and exposure to certain environmental toxins, such as Di-2-ethylhexyl phthalate (DEHP) and cadmium, as well as having testicular cancer. These factors can impact fertility by disrupting hormone balance, reducing sperm quality, and increasing the risk of infertility 1. For example, older males have mildly reduced fertility, and males with obesity have mildly reduced fertility due to metabolic syndrome 1. Additionally, exposure to certain environmental toxins, such as DEHP, has been associated with lower sperm quality, including reduced sperm concentration, motility, and increased DNA damage 1.
Risk Factors for Infertility
- Age: Older males have mildly reduced fertility 1
- Obesity: Males with obesity have mildly reduced fertility due to metabolic syndrome 1
- Poor diet: Poor diet results in reduced fertility 1
- Smoking: Smokers have slightly reduced fertility 1
- Anabolic steroid use: Anabolic steroid use is associated with reduced fertility 1
- Stress: Stress is associated with reduced sperm progressive motility 1
- Environmental toxins: Exposure to certain environmental toxins, such as DEHP and cadmium, is associated with reduced fertility 1
- Testicular cancer: Those with testicular cancer have reduced fertility 1
Importance of Comprehensive Testing
Comprehensive testing for these factors may be beneficial for those struggling with unexplained infertility, including evaluation of lifestyle factors, environmental toxin exposure, and medical history 1. Clinicians should recommend karyotype testing for males with primary infertility and azoospermia or sperm concentration <5 million sperm/mL when accompanied by elevated FSH, testicular atrophy, or a diagnosis of impaired sperm production 1.
Surgical Sperm Retrieval
In cases where azoospermia is present, micro-TESE may be a viable option for sperm retrieval, with a higher success rate compared to non-microsurgical testis sperm extraction and conventional TESE 1. However, this procedure carries risks, including decreased postoperative testosterone levels and potential need for testosterone replacement therapy 1.
From the Research
Overlooked Causes of Infertility
- Thyroid disorders, including hypothyroidism and hyperthyroidism, can lead to infertility in women 2, 3, 4, 5, 6
- Untreated hypothyroidism can cause ovulatory dysfunction, resulting in oligo-amenorrhea, and decrease the chances of achieving a pregnancy following IVF 2, 4
- Hyperprolactinemia, which can be caused by hypothyroidism, can also affect fertility 4
- Acromegaly and Cushing's disease may impair fertility, although the mechanisms are not well defined 3
- Autoimmunity, such as thyroid autoimmunity (TAI), can also play a role in infertility 5
- Polycystic ovary syndrome (PCOS) and primary ovarian insufficiency are common endocrine disorders that can cause infertility 3
- Hypothalamic causes of female infertility, such as hypogonadotropic hypogonadism, should be considered in the appropriate clinical context 3
Endocrine Disorders and Infertility
- Endocrine disorders, such as thyroid disorders, can interact with the ovaries and affect fertility 3, 4, 5
- The interplay between the endocrine organs and the ovaries can make diagnosis of infertility challenging 3
- Treatment of endocrine disorders, such as levothyroxine for hypothyroidism, can improve fertility outcomes 2, 4, 5
Screening and Treatment
- Women with infertility should be screened for thyroid disorders, including hypothyroidism and hyperthyroidism 5, 6
- Women with thyroid autoimmunity (TAI) may require treatment with levothyroxine, even if they are euthyroid 5
- Serum TSH levels should be targeted to <2.5 mIU/L in women undergoing assisted reproductive technology (ART) 5