宫颈帽,是一种帽形的阴道内避孕工具,它能盖住妇女的子宫颈,使精子不能进入宫腔而达到避孕目的。随着人们对机械阻隔式避孕工具的重新重视,近几十年来,又研究发展了阀式宫颈帽。安装在阀式宫颈帽上的单向阀,其正向开启特性能使宫腔分泌液流入阴道,而其反向特性能阻止精子进入宫腔。因此,它能较长时间地使用,克服了现有外用避孕工具不能较长时间使用的缺点。同时,由于它是一种机械阻隔式的避孕工具,且放置在子宫的非敏感部位,所以,它不会引起全身性的副作用, Cervical caps, is a hat-shaped intravaginal contraceptive tool, it can cover the woman’s cervix, so sperm can not enter the uterine cavity to achieve the purpose of contraception. With the renewed emphasis on mechanical barrier contraceptives, valve-type cervical caps have also been developed in recent decades. A one-way valve mounted on a valve-type cervical cap has a positive opening feature that allows the uterine fluid to flow into the vagina while its reverse feature prevents sperm from entering the uterine cavity. Therefore, it can be used for a long time, overcoming the shortcomings that existing external contraception tools can not be used for a long time. At the same time, it does not cause generalized side effects because it is a mechanically-blocked contraceptive and is placed on the non-sensitive part of the uterus,