Stanford JB, Smith KR, Dunson DB. Vulvar mucus observations and the probability of pregnancy. Obstet Gynecol (2003) 101(6):1285–93.
The highest probability of pregnancy occurred on the peak day of vulvar mucus observation (.38 for normally fertile couples and.14 for subfertile couples). The probability of pregnancy was greater than.05 for normally fertile couples from 3 days before to 2 days after the peak, and for subfertile couples from 1 day before to 1 day after the peak. The cycle-specific probability of conception correlated with the quality of mucus discharge in normally fertile couples but not in subfertile couples.
Standardized vulvar observations of vaginal mucus discharge identify the days with the greatest likelihood of conception from intercourse in normal fertility and subfertility and provide an indicator of the overall potential for conception in a given menstrual cycle in normal fertility.