The early amniocentesis study: a randomized clinical trial of early amniocentesis versus midtrimester amniocentesis

Fetal Diagn Ther. 1996 Mar-Apr;11(2):85-93. doi: 10.1159/000264285.


Objectives: 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.

Publication types

  • Clinical Trial
  • Comparative Study
  • Randomized Controlled Trial
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amniocentesis*
  • Feasibility Studies
  • Female
  • Humans
  • Karyotyping
  • Pilot Projects
  • Pregnancy
  • Pregnancy Outcome
  • Pregnancy Trimester, First
  • Pregnancy Trimester, Second
  • Prospective Studies
  • Risk Assessment