CONFINED PLACENTAL MOSAICISM, IUGR, AND ADVERSE PREGNANCY OUTCOME - ACONTROLLED RETROSPECTIVE UK COLLABORATIVE SURVEY

In a retrospective collaborative study involving 21 U.K. laboratories and 11 775 CVS prenatal diagnostic procedures, a total of 73 cases of confined placental mosaicism (CPM) were identified among the 8004 firs t-trimester referrals because of advanced maternal age, a previous chi ld with a numerical chromosome abnormality, or a family history of the same. Data were collected on subsequent cytogenetic follow-up and pre gnancy outcome for each case and a referral matched control. Compariso n with the control population failed to demonstrate a marked increase in adverse pregnancy outcome in the CPM group, but a significant incre ase in both low and high birth weight infants was recorded. In a paral lel study, 7 out of 108 cases, referred for prenatal diagnosis because of ultrasound detection of isolated intrauterine growth retardation ( IUGR) in the second or third trimester, were shown to have a chromosom e abnormality restricted to the extraembryonic tissues. These included cases of CPM involving trisomy 9 and del(13)(q13), neither of which h as previously been reported in association with IUGR.