The early amniocentesis study: a randomized clinical trial of early amniocentesis versus midtrimester amniocentesis.
OBJECTIVE
The primary purpose of this pilot study was to determine whether the safety of early amniocentesis (EA; 11 weeks to 12 weeks and 6 days) is similar to midtrimester amniocentesis (MA; 15 weeks to 16 weeks and 6 days). The secondary objectives were to determine the cytogenetic success and accuracy of EA compared with MA.


METHODS
This prospective, randomized clinical trial compared continuous ultrasound-guided EA and MA (22-gauge needle) in patients at a late maternal age (> or = 35 years). The procedures were compared for safety, success and accuracy.


RESULTS
Among the 683 women randomized and followed to pregnancy completion, there was a total of 27/344 (7.8%) and 25/339 (7.4%) fetal losses (spontaneous and induced abortions) in the EA and MA groups, respectively (difference 0.4%; CI -3.6 to 4.4%). The rate of postprocedure spontaneous fetal loss was 2.4% (8/330) in the EA group and 3.3% (10/299) in the MA group (NS). The procedure success rate at the first attempt was 97.6% in the EA group and 99.7% in the MA group. There were no diagnostic errors, and all but 2 EA cultures were successful (both repeated successfully). The perinatal outcome was similar in both groups.


CONCLUSIONS
EA appears to be as safe and accurate as MA. A large multicentered, randomized trial is currently underway to verify these results.
Johnson
J M
JM
Department of Obstetrics and Gynecology, University of Toronto, Canada.
Wilson
R D
RD
Winsor
E J
EJ
Singer
J
J
Dansereau
J
J
Kalousek
D K
DK
D000649:Amniocentesis; D005240:Feasibility Studies; D005260:Female; D006801:Humans; D007621:Karyotyping; D010865:Pilot Projects; D011247:Pregnancy; D011256:Pregnancy Outcome; D011261:Pregnancy Trimester, First; D011262:Pregnancy Trimester, Second; D011446:Prospective Studies; D018570:Risk Assessment