There are a few diagnostic tools available to detect chromosomal abnormalities after a tubal reversal pregnancy occurs. Many women who had previously chosen to have their tubes closed are undergoing tubal reversal procedures many years later for want of another child or two. When a pregnancy occurs after the tubal reversal, some concerns crop up about conceiving a child with Down syndrome. These tests are not solely done for mothers after a tubal reversal pregnancy. Parents with a history of chromosomal abnormalities in the family are also encouraged to have these tests as well.

Second Trimester Screening Test for Down Syndrome

A Quad Screen is a maternal blood screening test that is similar to the Triple Screen Test (also know as AFP Plus and the Multiple Marker Screening). However, the Quad Screen looks for not only the three specific substances evaluated in those tests (AFP, hCG, and Estriol) but also a fourth substance known as Inhibin-A. It is done mainly to determine the risk of the pregnant mother carrying a child with Down syndrome. This blood analysis is usually performed between the 16th and 18th week of pregnancy. A high-risk mother is then advised to have further testing which will analyze cells from the fetus for the presence of structural chromosomal problems.

First Trimester Screening Test for Down Syndrome

Nuchal translucency ultrasound is a diagnostic tool used to evaluate the fetus for Down syndrome. It is performed between 11 to 13 weeks of pregnancy, and is usually combined with a plasma protein-A analysis. Lower levels of plasma protein-A from the 8th to the 14th week of gestation can indicate increased risk for Down syndrome and other gestational problems such as intrauterine growth restriction and premature delivery.

Other Tests Performed After a Tubal Reversal Pregnancy

Aside from the Quad Screen test, there are other tests which can be done following a tubal reversal pregnancy.

— Determination of inhibin A (IH-A)

— Amniocentesis

— Chorionic villus sampling (CVS)

— Percutaneous umbilical cord blood sampling (PUBS)

— Preimplantation genetic diagnosis (PGD)

A Quad Screen is a maternal blood screening test that is similar to the Triple Screen Test (also know as AFP Plus, the Kettering test, the Bart’s test, and Multiple Marker Screening). However, the Quad Screen looks for not only the three specific substances evaluated in those tests (AFP, hCG, and Estriol) but also a fourth substance known as Inhibin-A. It is done mainly to determine the risk of the pregnant mother carrying a child with Down syndrome. Many patients who have had a tubal ligation reversal are older and will opt for this screening test. This blood analysis is usually performed between the 16th and 18th week of pregnancy. This is used to categorize a patient as either high-risk or low-risk. A high-risk mother is then advised to have further testing which will analyze cells from the fetus for the presence of structural chromosomal problems.

What is meant by a positive Quad Screen?

A positive test means having a high risk of chromosomal abnormalities or neural tube defects. The Quad Screen can be implicated as an early precursor with an extensive deal of ensuing scientific improvements to deal the underlying problems. Patients with a positive screening are then further recommenced for more insightful and specific procedures. Most tubal reversal patients will elect to undergo invasive procedures such as an amniocentesis.

Sensitivity adjustments of the Quad Screen:

Although 78% sensitivity and 5% false-positive rate of the test makes it widely available in most countries as a common option to classify risk, the estimated sensitivity of the risk is calculated and attuned on certain factors including:

o the expectant mother’s age

o diabetic condition of the mother

o twins or other multiple gestation

o the gestational age

o weight of the mother

o ethnicity may also be adjusted in markers

These factors influence the markers, and thus interpretation is indicated for the increased risk.

Integrated Screening

This involves combined first-trimester nuchal translucency and PAPP –A, plus second-trimester Quad Screening, and improves sensitivity to 90%. As most tubal reversal pregnancies occur in older patients, many will opt for the Integrated Screen.

Limitations of the Quad Screen:

1. The test is not for a definite diagnosis

2. The test is only a precursor for more predictive amniocentesis.

3. The age of the mother is indicative for amniocentesis.

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.