Women with DZ twins can be counselled that the chance of their pregnancy producing a child with Down's syndrome is theoretically double their age-related risk, whereas women with MZ twins simply have their age-related risk that both twins will be aneuploid. Nevertheless, there is some evidence that Down's syndrome may occur less frequently in twins [17,18]. Serum screening is inapplicable in multiple pregnancy, because aberrant placental or fetal hepatic hormone production in an affected twin is masked by normal levels from the unaffected co-twin. In contrast, nuchal translucency, although rarely used in isolation any more in singletons because of its high false positive rate, is readily applicable as a fetally-specific marker. Because the background rate of increased neckfolds is doubled in MC twins, the average of the twins' measurements is used to avoid high false positive rates .
Was this article helpful?
Once your pregnancy is over and done with, your baby is happily in your arms, and youre headed back home from the hospital, youll begin to realize that things have only just begun. Over the next few days, weeks, and months, youre going to increasingly notice that your entire life has changed in more ways than you could ever imagine.