Fertility & Infertility
Fertility care is defined by prevention, diagnosis and treatment of infertility.
Reproduction is normally achieved through unprotected and systematic sexual intercourse, where depending on the age and reproductive dynamics of the couple, the probability of natural conception ranges at an optimum between 20-37% in the first three months of trying. According to the age of the woman and as an indication, this percentage will form around 20% at 30 years of age, while at 40 years this percentage decreases to only 5%.
Successful reproduction is a complex and multifactorial biological process by which the two genetic materials combine to form a genetically novel organism. The crucial initial stages of the reproductive process require:
- Functional sperm, capable of overcoming the natural barriers of the female reproductive system to reach the fallopian tube and interact harmoniously with the oocyte
- Adequate hormonal action and support of the ovarian function for the development and release of an oocyte with gradual cell maturity and susceptibility to fertilization
- Functional properties of the oocyte to initiate and carry out the key processes involved in the coupling of the genetic material deriving from the sperm and the oocyte to form a diploid cell
- Continuous mitotic divisions from which the somatic cells of the developing embryo emerge and during which corrective mechanisms may act to protect genetic integrity
- Relocation of the embryo at blastocyst stage (5th – 6th day of development) from the fallopian tube to the uterus, with endometrial lining displaying adequate receptivity characteristics (thickness and physiology)
- The synchronized biochemical “dialogue” during the attachment of the embryo to the endometrium and the completion of the implantation on the 9th day of early embryonic development
- The adequate hormonal support of pregnancy with simultaneous embryological development and progression through the complex organogenesis and structures of the new organism
The outmost important factor for the successful completion of the above processes is fertility, a dynamic situation with three interconnected levels of organization:
- The endocrine action that regulates the secretion of reproductive hormones and their ideal balance through feedback mechanisms
- The adequate anatomy and physiology of the reproductive system for the production/maturation/transfer of gametes (oocytes, sperm) and for the support of pregnancy
- The functional capacity of oocytes and sperm, including their genetic integrity
Fertility, apart from the biological procedures, also depends on external factors such as the environment, diet, lifestyle, sexual behavior, frequency of intercourse, cultural-social- and religious beliefs, economic and social status and emotional fluctuations.
Infertility & Causes
- Is a common medical problem that includes a wide range of pathologies or unexplained causes that complicate family expansion.
- Is defined as the failure to conceive after 12 or more months of regular unprotected sexual intercourse, or following diagnosis through specialized medical examinations.
- Affects millions of people worldwide, with clinical studies reporting estimates of 48 million couples and 186 million individuals with fertility problems throughout the globe.
- May be either primary or secondary. In primary infertility there is no history of pregnancy, while in secondary infertility at least one previous pregnancy has been recorded regardless of its outcome.
- Its effects on mental and physical health can be significant, often leading to additional social and economic burdens.
The causes of infertility can be found in multiple and often combined factors.
INFERTILITY FACTORS
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Male factor
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30-50%
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Tubal factor
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25-30%
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Ovarian dysfunction
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10-50%
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Endometriosis
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10-20%
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|
Unexplained infertility
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20-30%
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RCOG, 2004; Bhattacharya et al, 2009; Mascarenhas et al, 2012
Male Infertility
The male infertility is mainly attributed to isolated and combined sperm disorders (oligozoospermia, asthenozoospermia, teratozoospermia), absence of sperm in seminal fluid (azoospermia) and to erectile and ejaculatory dysfunction. Equally important are the functional capacity of sperm and the integrity of the contained genetic material.
The main causes that lead to male infertility are:
- Cryptorchidism
- Varicocele, hydrocele, inguinal hernia
- Sperm duct dysplasia (Cystic Fibrosis, Young syndrome)
- Occlusion of the seminal vesicles (congenital or iatrogenic disorder)
- Congenital testicular disorders (Klinefelter syndrome, Y-microdeletions)
- Hypogonadotrophic hypogonadism (Kallmann syndrome, Prader-Willi, Lawrence-Moon-Beidl, pituitary tumors)
- Inflammations in the urogenital system (orchitis, epididymitis, prostatitis, urethritis)
- Erectile and sexual dysfunction (inability to ejaculate, premature ejaculation)
- Retrograde ejaculation (spinal cord injuries, neuropathy)
- Malignant manifestations and consequently the therapeutic approach with surgery, radiation, chemotherapy
- Endocrine disorders (hypothyroidism, hyperprolactinaemia)
- Immune disorders and production of antisperm antibodies
- Extensive exposure to radiation or chemical agents
- Hyperthermia of the testicles due to occupational/lifestyle exposure
- High fever
- Diet and lifestyle factors - harmful habits
- Use of steroids, drugs and certain medications
- Surgery in the genital area
- Injury or testicular torsion
- Idiopathic infertility
Female Infertility
The female reproductive system is a physiologically complex system as in addition to the contribution of the individual’s genetic material (oocyte), it “hosts and nurtures” the interaction of gametes (sperm and ova), fertilization and pregnancy.
The main causes of female infertility are:
- Tubal factor with congenital (structural abnormalities) or acquired tubal lesions (adhesions, inflammation, surgery, hydrosalpinx, endometriosis)
- Ovulation disorders (hypothalamic and pituitary disorders, Kallmann syndrome, Sheehan syndrome, adenoma, prolactinoma-hyperprolactinaemia, tumors and inflammation of the central nervous system)
- Ovarian dysfunction (polycystic ovaries and polycystic ovary syndrome, premature ovarian failure, surgery, Cushing's disease, gonadal dysgenesis)
- Endometriosis which determines the presence of ectopic endometrial tissue in locations other than the uterine cavity disrupting the normal function of the ovaries and the environment of the fallopian tubes and endometrium
- Anatomy and physiology of the uterus (septated –bicornuate uterus, fibroids, endometrial polyps, adhesions)
- Cervical factors (congenital anomalies, surgeries, cervical mucus quality)
- Malignant manifestations and consequently the therapeutic approach with surgery, radiation, chemotherapy
- Endocrine disorders (hypothyroidism, hyperprolactinaemia)
- Genetic factors (pathological karyotype, Fragile X syndrome, Turner syndrome and chromosome mosaics, genetic disorders: leptin, GnRH-FSH-LH-leptin receptors, SF1, DAX1, KAL1)
- Immune causes (rheumatoid arthritis, Crohn's disease)
- Diet and lifestyle factors - harmful habits
- Use of steroids, drugs and certain medications
- Idiopathic infertility
Age and lifestyle factors
Fertility decreases over time and this is evident in both females and males. The reproductive cycle has been significantly extended, especially in developed countries due to the pursuit of education and professional stability, which results in many couples choosing to delay childbearing.
In men, testosterone levels decrease progressively after the age of 35, with sperm parameters being negatively affected in terms of volume, concentration, motility and morphology. After the age of 40, there is an increased rate of DNA damage carried by sperm, reduced motility (~ 40%) and sperm viability (~ 50%).
On the female side, even though women are born with a significant supply of eggs, only 400 to 500 of them will eventually mature. With advancing age, the time required to achieve pregnancy increases due to the differentiation of endocrine and reproductive function, with an additional increase in the frequency of aneuploidy occurrence in the ovum.
Lifestyle factors such as body weight, exercise, psychological stress, smoking, alcohol, caffeine, drugs, certain medications, environmental and occupational exposure to radiation, fever, chemicals and harmful factors can have a significant effect on fertility. Some of these behaviors are modifiable and preventative care may prove beneficial. Tailored consultation by an expert can bring about positive changes and improve your chances of getting pregnant.
References
- American Society of Reproductive Medicine. Infertility: An Overview. Patient Information Series 2012 (http://www.fertilityanswers.com/wp-content/uploads/2016/04/infertility-an-overview-booklet.pdf).
- World Health Organization (WHO). International Classification of Diseases, 11th Revision (ICD-11) Geneva: WHO 2018.
- Mascarenhas MN, Flaxman SR, Boerma T, et al. National, regional, and global trends in infertility prevalence since 1990: a systematic analysis of 277 health surveys. PLoS Med 2012;9(12):e1001356. doi: 10.1371/journal.pmed.1001356 [published Online First: 2012/12/29]
- Boivin J, Bunting L, Collins JA, et al. International estimates of infertility prevalence and treatment-seeking: potential need and demand for infertility medical care. Human reproduction (Oxford, England) 2007;22(6):1506-12. doi: 10.1093/humrep/dem046 [published Online First: 2007/03/23]
- Bhattacharya S, Maheshwari A, Mollison J. Factors associated with failed treatment: an analysis of 121,744 women embarking on their first IVF cycles. PLoS One 2013;8(12):e82249.
- Mascarenhas MN, Flaxman SR, Boerma T, et al. National, regional, and global trends in infertility prevalence since 1990: a systematic analysis of 277 health surveys. PLoS Med 2012;9(12):e1001356.
- Practice Committee of the ASRM – American Society for Reproductive Medicine. Report on optimal evaluation of the infertile male. Fertil Steril 2006a; 86: S111-4.
