Male
Factor Infertility
What
is infertility?
Infertility is defined by the American Society for
Reproductive Medicine (ASRM) as a disease of the reproductive system that
impairs the body’s ability perform the basic function of reproduction.
Although conceiving a child may seem to be simple and natural, the
physiological process is quite complicated and depends on the proper
function of many factors, including the following, as listed by the ASRM:
-
production
of healthy sperm by the man
-
production
of healthy eggs by the woman
-
unblocked
fallopian tubes that allow the sperm to reach the egg
-
the
sperm’s ability to fertilize the egg
-
the ability
of the fertilized egg to become implanted in the uterus
-
adequate
embryo quality
Who
is affected by infertility?
The average chance to conceive for a normally fertile couple having
regular, unprotected intercourse is approximately 25 percent during each
menstrual cycle. In most couples, conception occurs within about 12
months. However, infertility affects about 10 percent of couples of
childbearing age. Infertility is not just a woman’s concern. A problem
with the male is the sole cause, or a contributing cause, of infertility in
about 40 percent of infertile couples. About one-fourth of infertile
couples have more than one cause or factor related to their inability to
conceive. About 10 to 15 percent of couples have no identifiable cause for
their infertility after medical investigation.
What are the risk factors for men regarding
infertility?
The following is a list of risk factors related
to male infertility (also called male factor or male factor infertility):
- history
of prostatitis or genital infection
- testicular
trauma or torsion
- history
of precocious puberty (puberty occurring at a young age) or delayed
puberty (puberty occurring at an older age)
- exposure
to toxic substances or hazards on the job, such as lead, cadmium,
mercury, ethylene oxide, vinyl chloride, radioactivity, and x-rays
- cigarette
or marijuana smoke
- heavy
alcohol consumption
- exposure
of the genitals to high temperatures
- prescription
drugs for ulcers or psoriasis
- DES
taken by mother during pregnancy
What causes male factor infertility?
The main causes of male infertility can be divided into the following
categories:
- sperm
disorders
Problems with the production and maturation of sperm are the
most common causes of male infertility. Sperm may be immature,
abnormally shaped, or unable to move properly. Or, normal sperm may be
produced in abnormally low numbers (oligospermia) or seemingly not at
all (azoospermia). This problem may be caused by many different
conditions including the following:
- infectious diseases or inflammatory conditions such
as the mumps virus
- endocrine or hormonal disorders such as Kallman's
syndrome or pituitary problem
- immunological disorders in which some men produce
antibodies to their own sperm
- environmental and lifestyle factors
- genetic diseases (most are associated with sperm
abnormalities, either directly or indirectly):
-
cystic
fibrosis - an inherited condition that typically involves the
lungs and pancreas, but can present also as a cause of infertility
with or without mild sinus problems; 6 to 10 percent of men with
obstructive azoospermia have congenital bilateral absence of the
vas deferens (CBAVD), which means they were born without the vas
deferens; of these, 70 percent may have cystic fibrosis or carry a
mutation in the cystic fibrosis gene.
-
Noonan
syndrome - an inherited condition which can occur in either
males or females. In males, this syndrome can cause abnormal
gonadal (testicular) function.
-
myotonic
dystrophy - an inherited condition with progressive
multi-system involvement, resulting in infertility (underdeveloped
testes and abnormal sperm production), in some cases.
-
hemachromatosis
- an inherited condition affecting iron storage. Eighty percent of
men with hemochromatosis have testicular dysfunction.
-
sickle
cell disease - an inherited condition affecting the normal
production of hemoglobin.
-
sex
reversal syndrome - a male who has the sex chromosomes of a
genetic female (XX, instead of XY), resulting in azoospermia and
other characteristics.
-
androgen
receptor gene mutations - an inherited condition in which a
man is genetically male (46,XY), but has infertility due to a
defect in receptors for testosterone.
-
chromosomal
abnormalities - men with an extra X sex chromosome, known as
Klinefelter syndrome, often do not produce sperm or produce very
low quantities of sperm.
-
chromosome
rearrangements - in some persons, there are the usual number
of chromosomes (46) in the nucleus (center) of cells, but
rearrangements in the chromosome material, where a piece of a
chromosome has exchanged places with another, has taken place; men
with either azoospermia or oligospermia have a higher frequency of
chromosome rearrangements than is found in the general population.
-
deletions
in the Y chromosome - in some persons, there are the usual
number of chromosomes (46) in the body cells, but small sections
of the Y chromosome are missing or deleted; anywhere from 3 to 30
percent of men with either azoospermia or oligospermia have
deletions in the Y chromosome.
| It is important to
understand that men who have genetic problems which cause their
infertility, such as a deletion in the Y chromosome, can pass
this problem to their sons, who would also have infertility, if
they elect to use their own sperm in achieving a pregnancy. |
- anatomical abnormalities
Obstructions of the genital tract can cause infertility by
partially or totally blocking the flow of seminal fluid. Some of these
abnormalities may be of congenital (present at birth) origin or the
result of a genetic defect. Others could have occurred due to
infection or inflammation of the urogenital tract, surgery that left
scar tissue in the genital tract, or the presence of varicose veins in
the scrotum (scrotal varicoceles).
- immotile
cilia syndromes
In this condition, the sperm count
is normal but the spermatozoa are non-motile such as in Kartagener's
syndrome, an inherited disorder.
- mitochondrial
deletions
Mitochondria are structures in the
cell responsible for energy production. There are actually a set of
genes in the mitochondria, separate from the normal chromosome set
contained in the nucleus. Recently, it has been discovered that these
genes, when altered or deleted, can affect a person’s health and/or
fertility.
- liver
disease, renal disease, or treatment for seizure disorders
- other
factors
Other factors may arise from the defective delivery of sperm into the
female genital tract, which could be caused by impotence or premature
ejaculation.
How is male factor infertility diagnosed?
In addition to a complete medical history and physical
examination, diagnostic testing for male factor infertility may include
the following:
- multiple
semen analysis - at least two semen examples are collected on
separate days to examine the semen and sperm for various factors, such
as semen volume, consistency, and pH, and the sperm count, motility,
and morphology (shape).
- other
tests (to determine the cause of sperm abnormalities or diseases
of the male reproductive system)
Treatment
for male factor infertility:
Specific treatment for male factor infertility will
be determined by your physician based on:
-
your
age, overall health, and medical history
-
extent
of the disease
-
your
tolerance for specific medications, procedures, or therapies
-
expectations
for the course of the disease
-
your
opinion or preference
There is a range of treatment options currently available for male
factor infertility. Treatment may include:
- assisted
reproductive technologies (ART)
This type of treatment may include the following:
- artificial insemination
Artificial insemination involves the placement of relatively
large numbers of healthy sperm either at the entrance of the cervix
or into the partner's uterus, bypassing the cervix, to have direct
access to the fallopian tubes.
- IVF, GIFT, and other techniques
In vitro fertilization (IVF) or gamete intra-fallopian transfer
(GIFT) have been used for the treatment of male infertility. As is
the case with artificial insemination, IVF and similar techniques
offer the opportunity to prepare sperm in vitro, so that oocytes are
exposed to an optimal concentration of high quality, motile sperm.
- microsurgical fertilization (microinjection techniques such as
intracytoplasmic sperm injection, or ICSI)
This treatment is used to facilitate sperm penetration by injection
of a single sperm into the oocyte. Fertilization then takes place
under the microscope.
- drug
therapy
A small percentage of infertile men have a hormonal disorder that can
be treated with hormone therapy. Hormonal imbalances caused by a
dysfunction in the mechanism of interaction between the hypothalamus,
the pituitary gland, and the testes directly affect the development of
sperm (spermatogenesis). Drug therapy may include gonadotrophin
therapy, antibiotics, or another medication deemed appropriate.
- surgery
Surgical therapy in male infertility is designed to overcome
anatomical barriers that impede sperm production and maturation or
ejaculation. Surgical procedures to remove varicose veins in the
scrotum (varicocele) can sometimes serve to improve the quality of
sperm.
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