By Chioma Umeha
Genetic causes of female infertility – Many women
are unable to conceive and deliver a healthy baby due to genetic factors.
Sometimes this is due to an inherited chromosome abnormality. Other times it is
because of a single-gene defect passed from parent to child.
In addition, if other women in your family have
had problems conceiving due to premature menopause, endometriosis or other
factors, you may be at increased risk of the same problems.
Chromosome abnormalities
Chromosomally abnormal embryos have a low rate of
implantation in the mother’s uterus, often leading to miscarriages. If an
abnormal embryo does implant, the pregnancy may still result in miscarriage or
the birth of a baby with physical problems, developmental delay, or mental
retardation.
There are several kinds of chromosome
abnormalities:
• A
missing piece of a chromosome (deletion)
• An
upside-down chromosome (inversion)
• A
change in the gene’s DNA sequence (mutation)
• Too
many or too few chromosomes (aneuploidy)
• Chromosome
pieces attached to the wrong chromosome (translocation)
• Translocation
is the most common of these. Although a parent who carries a translocation is
frequently normal, his or her embryo may receive too much or too little genetic
material, and a miscarriage often results.
• Couples
with specific chromosome defects may benefit from pre-implantation genetic
diagnosis (PGD) in conjunction with in vitro fertilization (IVF).
• Down
syndrome is usually associated with advanced maternal age and is a common
example of aneuploidy. Down syndrome is caused by having an extra number-21
chromosome (three instead of two). It is also referred to as trisomy 21.
• Inherited
genetic diseases
• Very
rare is the existence of an inherited genetic disease due to abnormal genes or
mutations. Chromosome analysis of the parents’ blood identifies such an
inherited genetic cause in less than 5 percent of couples.
• Single-gene
abnormalities are mutations caused by changes in the DNA sequence of a gene,
which produce proteins that allow cells to work properly. Gene mutations alter
the functioning of cells due to a lack of a protein.
