Trisomy 21 or Down Syndrome

Parental Concerns:

Many women who have had their fallopian tubes ligated are choosing to undergo tubal reversal procedures in order to have one or more children again.  Tubal reversal is a surgical operation that restores a woman’s ligated tubes back to normal and allows pregnancy to occur.  There are some concerns, however, that a woman above the age of 40 who had a tubal reversal has an increased risk of conceiving a child with trisomy 21 or Down syndrome.

Definition of Trisomy 21:

Every cell in the human body contains 23 pairs of chromosomes.  In trisomy 21 individuals an extra chromosome 21 is present. Most cases are due to random mutations occurring during egg or sperm cell formation.   Children with trisomy 21 have common physical features.  They usually have weak muscles, small and flat heads, wide nasal bridges, and a single crease on their palms.  They also have delayed mental growth.  Some affected children have heart defects and gastrointestinal problems as well.

Genetic Epidemiology In the General Population:

Trisomy 21 occurs in one newborn out of every 800 live births.  According to a study from the Center for Disease Control and Prevention, in the US

approximately 95% of all chromosomal abnormalities are due to trisomy 21.  Downs syndrome appears in all ethnic groups and in all economic classes of human race.

Maternal age influence:

Maternal age is an important contributing factor in conceiving a baby with Down syndrome.  At the ages between 20 and 24, the probability of having an affected child is one out of 1,562 live births.  Between the ages of 35 and 39, it is one in 214 live births.  Above the age of 45, this risk increases to 1 in every 19 live births.   Recent studies have also found that paternal age above 42 years could be another risk factor for the development of Downs syndrome.

Severity of Downs syndrome:

Manifestations of Downs syndrome range from mild to moderate to severe forms.  Most affected children present with moderate mental retardations as well as delayed physical and social developments.  Although there is no known therapy to cure the condition, children with Downs syndrome usually live well into their adulthood.

Tubal Reversal and Down Syndrome:

Women who choose to undergo tubal ligation reversal at an older age (40 and above) must explore their options before making a decision. Advanced age increases the risk of conceiving a child with chromosomal abnormalities such as Downs syndrome. Pregnancy at an advanced age, whether by tubal ligation reversal surgery or not, always puts on at increased risk of having a child with a chromosomal abnormality.

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