Repeat: The study was on the Rhythm Method, not more contemporary iterations of so-called Natural Family Planning.
The study's conclusion comes as something of a no-brainer to Your Faithful Correspondent, who once cohabitated with a gal who would never leave home without her basal body thermometer.More here.
The Rhythm Method wasn't as convenient as popping pills that did strange thing to a woman's body or keeping one's leg's closed, but by cricky it worked, although there is that connection between being at one's most fertile and . . . er, randiness that requires some discipline.
And while you didn't ask, we didn't use condoms. So yes, it was all on her. Shame on me.
Hat tip to Feministing. Image by Robert Everest.