FIRST TRIMESTER AMNIFILTRATION - TECHNICAL, CYTOGENETIC AND PREGNANCYOUTCOME OF 104 CONSECUTIVE PROCEDURES

Objective To investigate the technical, cytogenetic and pregnancy comp lications of first trimester amnifiltration for the diagnosis of fetal karyotype. Design Observational study. Setting The fetal medicine uni t, UMDS St Thomas' Campus, London. Subjects One hundred and four women seeking prenatal diagnosis of fetal karyotype. Main outcome measures Sampling success, culture rate, harvest time and karyotype, pregnancy outcome and complications. Results Sampling was successful in all 104 cases, but equipment failure forced the procedure to be changed to ear ly amniocentesis in eight (7%) cases. The karyotype was normal in 101 (97%) cases, abnormal in three. The mean harvest time was 14 days (ran ge 9-26 days; SD = 3.4), and three cultures failed (2.8%). Pregnancies resulted in 99 (95%) live births, with a mean gestation of 277 days ( range 182-300 days; SD = 16). There was one termination for trisomy 21 and four spontaneous miscarriages (3.8%). Amniotic fluid leakage occu rred in six cases (5%), all resulted in live births, five at term and one at 35 weeks. Conclusions This study demonstrates that amnifiltrati on is technically possible in the first trimester of pregnancy, and th at samples can be successfully karyotyped. The harvest time for cultur e is similar to early amniocentesis and chorion villus sampling. The r ate of fetal loss, adjusted by the estimated natural loss, is 1.7%, wh ich compares favourably with both chorionic villus sampling and early amniocentesis.