Infertility : definition, causes and investigation

Definition

Infertility can be defined as inability of couples to conceive after 1 year or more of trying.

There are few terms under infertility to describe different types of infertility: 1. Resolved infertility - pregnancies that occur after 1 year of trying without medical intervention, 2. Primary infertility - never pregnant, 3. Secondary infertility - failure to conceive after having previously delivered an infant without the use of infertility treatment.

Causes

Causes of infertility can be divided into male and female factors.

Female factors

Causes of female infertility includes disorder of ovulation, tubal disease, uterine/cervical pathology, endometriosis/pelvic adhesion and other pelvic pathology.

Problem with ovulation can be due to several medical conditions, which usually associated with hormonal abnormalities such as PCOS (polycystic ovarian syndrome) , hypothalamic amenorrhea, ovarian failure, hyperprolactinemia (e.g pituitary tumor), hypothyroidism, hyperandrogenism (e.g congenital adrenal hyperplasia, androgen-secreting tumors) and so on. Some medications also can cause anovulation thus affecting fertility. Besides that, problem with ovulation can also occur due to aging and diminished ovarian reserve.

Measurement of mid-luteal progesterone level, urinary luteinizing hormone using home prediction kit, and basal body temperature charting can be used to document whether ovulation occurs or not. If ovulatory dysfunction suspected, measurement of FSH, prolactin, thyroid-stimulating hormone, 17α-hydroxyprogesterone (if hyperandrogenism suspected), and testosterone (if hyperandrogenism suspected) can assist in identification of the etiology. In women older than 35 years old, assessment of ovarian reserve is recommended. The assessment includes: measurement of FSH and estradiol levels on day 3 of the menstrual cycle, clomiphene citrate (Clomid) challenge test, or transvaginal ultrasonography for antral follicle count.

Tubal blockage causing infertility either by preventing fertilization, in which the sperm unable to reach the ovum on time, or, by preventing fertilized ovum to go to uterine cavity for implantation. Uterine/cervical abnormalities also can be associated with infertility such as congenital uterine anomalies, fibroids, and polyps. Transvaginal sonography and hysterosalpingography allow assessment of the tubes, uterus and pelvis. Hysteroscopy might be done if hysterosalpingography reveals intrauterine abnormalities.

Endometriosis, pelvic adhesion and other pelvic pathology should be considered as causes that can lead to infertility and should be investigated after above causes has been rule out. More invasive procedure i.e laparoscopy might be done to diagnose these conditions.

-Male factors-

Causes of male infertility can be divided into: 1. Altered sperm transport, 2.Primary hypogonadism, 3.Secondary hypogonadism, 4.Abnormal spermatogenesis, 5.Idiopathic.

Men with altered/blocked sperm transport commonly presented with low volume of ejaculate or no ejaculate, which can be confirmed by doing a proper sperm analysis (showing low or no volume of semen). This could be due to erection/ejaculation problem or blockage of the sperm transport. Post ejaculatory urinalysis and transrectal ultrasonography may be performed to rule out retrograde ejaculation and ejaculatory duct obstruction respectively. Scrotal ultrasonography also can be helpful in assessing suspected testicular and scrotal abnormalities such as hydrocele and tumor.

Primary hypogonadism (primary testosterone insufficiency) , also referred as testicular failure or dysfunction, can be defined as insufficient production of testosterone due to testicular disorders. Meanwhile, secondary hypogonadism (secondary testosterone insufficiency), also referred as hypothalamic-pituitary dysfunction is defined as insufficient production of testosterone due to disorders of hypothalamus/pituitary gland. Hypogonadism (testosterone insufficiency) is suspected based on abnormal semen analysis (showing severe oligospermia-reduced number of sperm in semen or azoospermia-no sperm in semen). The relationship between serum FSH level , LH and testosterone can help to distinguish between primary and secondary hypogonadism. Measurement of serum prolactin level assists in detecting hyperprolactinemia that also can cause male infertility. Sometimes the level of LH, testosterone and prolactin are normal but only FSH is high or in the upper range of normal. These highly indicate abnormalities in spermatogenesis. However, many men with abnormal spermatogenesis can have a normal FSH level, thus a normal FSH level does not guarantee the presence of intact spermatogenesis.

In such cases where the initial evaluation unable to identify the causes of infertility, further specialized tests such as specialized sperm and semen studies might be recommended if identification of the cause of male infertility will direct the treatment of infertility.

Infertility evaluation

Generally, infertility evaluation should started after 1 year of unprotected intercourse during which pregnancy has not been achieved. Earlier evaluation may be indicated when there is presence of factors suggesting infertility such as history of pelvic inflammatory disease, amenorrhea, tubal surgery and so on. Other indication for earlier evaluation is the female partner is older than 35 years old. This is because fertility rates reduce and spontaneous abortion and chromosomal abnormality increase with advancing maternal age.

Components of infertility evaluation (history, physical examination and investigation)

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