Ostergard D R, Gunning J E
J Reprod Med. 1976 Sep;17(3):172-4.
A randomized, prospective study design compares the small Dalkon shield and the Copper T 200 (T Cu 200) intrauterine contraceptive devices in nulligravid women in the same clinic population during a 12-month period. This prospective study demonstrates statistically significant differences in the accidental pregnancy, expulsion and medical removal rates between the two devices. In nulligravid patients the T Cu 200 had lower event rates than the small shield in the categories of accidental pregnancy and medical removals for bleeding and pain.
一项随机前瞻性研究设计，在同一诊所人群中的未孕女性中，对小型达康盾宫内节育器和铜T 200（T Cu 200）宫内节育器进行了为期12个月的比较。这项前瞻性研究表明，两种节育器在意外妊娠、脱落及因医疗原因取出的发生率上存在统计学显著差异。在未孕患者中，就意外妊娠以及因出血和疼痛而进行医疗取出的情况而言，T Cu 200的发生率低于小型达康盾。
