Mauck Christine, Lai Jaim-Jou, Schwartz Jill, Weiner Debra H
CONRAD, 1611 Kent Street, No. 806, Arlington, VA 22209, USA.
Contraception. 2004 Apr;69(4):263-6. doi: 10.1016/j.contraception.2003.11.006.
The need for fitting a contraceptive diaphragm has recently been questioned in the context of upcoming trials in which the ability of the diaphragm to prevent sexually transmitted infections will be tested. Being able to provide the same size device to all women would greatly simplify supplying the device and training the clinicians, provided that it does not compromise effectiveness.
Data from studies of Lea's Shield and FemCap, in which all women were sized for a standard diaphragm and half were randomized to use it during the studies, were reanalyzed to determine if it was feasible to give all women in a barrier study the same size diaphragm or, alternatively, to determine if diaphragm size could be predicted using an algorithm of one or more parameters.
If all women received a size 70 diaphragm, rather than being fitted by a clinician, 33.2% would receive the same size that they would have received if they had been fitted by a clinician. If the definition of a "correct" fit were broadened to include one size larger or smaller than what the clinician would have prescribed, 78.0% would be "correctly" fitted. Using an algorithm that considered parity, body weight and other factors did not improve results.
It would be acceptable to conduct a trial in which all women receive a size 70 diaphragm, provided that all women are sized; that safety, effectiveness and acceptability are closely monitored and that study results are stratified by the diaphragm size determined by clinician fitting. It would also be informative to use sized diaphragms as the comparator in studies of new single-size devices.
在即将开展的试验中，避孕隔膜预防性传播感染的能力将接受测试，在此背景下，近期有人对是否有必要进行避孕隔膜适配提出质疑。倘若不影响避孕效果，能够为所有女性提供相同尺寸的避孕隔膜将极大地简化该器械的供应及临床医生的培训工作。
重新分析利氏避孕隔膜（Lea's Shield）和费姆卡普避孕帽（FemCap）的研究数据，这些研究中所有女性均按标准隔膜尺寸进行测量，且一半女性在研究期间被随机分配使用该隔膜，以确定在屏障法研究中为所有女性提供相同尺寸的隔膜是否可行，或者确定是否可以使用一个或多个参数的算法来预测隔膜尺寸。
如果所有女性均使用70号隔膜，而非由临床医生进行适配，那么33.2%的女性将获得与由临床医生适配时相同尺寸的隔膜。如果将“正确”适配的定义扩大到包括比临床医生所开尺寸大一号或小一号的情况，那么78.0%的女性将得到“正确”适配。使用考虑了生育情况、体重及其他因素的算法并未改善结果。
开展一项所有女性均使用70号隔膜的试验是可行的，前提是对所有女性进行尺寸测量；密切监测安全性、有效性和可接受性，并且研究结果按临床医生适配确定的隔膜尺寸进行分层。在新型单尺寸器械的研究中，将尺寸适配的隔膜用作对照也会很有意义。
