How is Trisomy 13 Diagnosed?
Due to the fact that Trisomy 13 has a distinctive set of physical characteristics, a doctor may be able make a diagnoses simply by performing a physical examination. The risk of Trisomy 13 does not increase as a result of a tubal reversal, but the risk does increase with age. To either rule out or verify this disorder, a small blood test can be performed. This blood test, a chromosomal analysis, allows doctors to ultimately verify the existence of an extra #13 chromosome.
Babies with Trisomy 13 generally have low birth weights and look premature even when they are at full-term. Babies with Trisomy 13 often have a small head with an inclined, or prone, forehead. This abnormality is due to structural malformations in the scull and in the brain. In babies with this particular genetic disorder, these characteristics can be identified after birth. Genetic disorders are not increased by a tubal reversal surgery.
Holoprosencephaly (a disorder that causes the front of the brain to be divided improperly) is also common in babies with Trisomy 13. Holoprosencephaly leads to structural problems in the growth of the baby’s face. These babies tend to have close-set eyes, cleft lips, and cleft palates. Their nostrils are not fully grown and their ears are low-set with abnormal shapes. In many cases, skin problems such as cutis aplasia (a scalp abnormality that looks like ulcers on the scalp), birthmarks (purplish-red in color), or hemangiomas (abnormal blood vessels) are also present.
Other major problems for Trisomy 13 babies include:
- Extra fingers and toes (polydactyly)
- Heart defects
- Kidney problems
- Abdominal wall disorders (omphalocele or gastroschisis)
- Malformations of the uterus
Diagnosis before birth
Any chromosomal abnormality, such as Trisomy 13, can be diagnosed before birth. The cells from the amniotic fluid or from the placenta can show defects. A fetal ultrasound (performed during a pregnancy) is not always 100 percent accurate, but can predict whether or not the fetus is at risk. To confirm the physical findings, a blood test can be taken and chromosomes can be analyzed to determine the presence of an extra #13 chromosome. As most tubal ligation reversal patients are older, and maternal age is a predictor for Trisomy 13, many tubal reversal patients will opt for definitive diagnosis prior to birth.
Correlation between Trisomy 13 and tubal ligation reversal
As a woman’s age increases, her chances of having a baby with a chromosomal abnormality also increases. Most women who desire a tubal reversal are older than the average woman trying to get pregnant. In general, the woman who opts for tubal reversal has previously had at least a couple of children before she decided to have her tubal ligation performed. Since these women are older, they are at increased risk for chromosomal abnormalities due to their age, and not due to the actual tubal reversal surgery. A tubal ligation reversal has no affect whatsoever on the risk of a Trisomy 13 or any other chromosomal abnormality.