<P> Generally the risks are very low if there are no other risk factors . If no additional abnormalities are detected by a thorough "level II" ultrasound, the likelihood the fetus has trisomy 18 is very low . </P> <P> A meta - analysis of 8 studies between 1990 and 2000 with choroid plexus cysts that were identified in second - trimester (an incidence of 1.2%). The incidence of the cysts in women younger than 35 was 1% (n = 1017). The study found no cases of trisomy 18 in fetuses with cysts whose mother was younger than 35 . The study concluded that "there is no evidence that detection of isolated choroid plexus cyst in women who are <35 years of age increases the risk of trisomy 18". </P> <P> Other factors which may have a bearing on the baby's chances of developing chromosome problems include: </P> <Ul> <Li> mother's age at the expected date of delivery </Li> <Li> the results of serum screening; XAFP triple testing or quad screening </Li> <Li> evidence of other "fetal findings" seen at the time of the ultrasound that may suggest a chromosome problem </Li> </Ul>

Icd 10 code for choroid plexus cyst in pregnancy