The fertile window period is defined as the 6-day period ending on the day of ovulation (Brosens 2006). Intercourse is mostly likely to result in pregnancy when it occurs within this period. The peak fecundability was observed when intercourse occured within 2 days prior to ovulation (Wilcox 1995). It is desirable to predict the fertile window period and ovulation, to optimize conception rate but can be challenging with the available methods. Amongst the methods available, include calendar method, basal body temperature (BBT), urinary LH detection, cervical mucus monitor, urinary estrogen metabolites and transvaginal ultrasound scan for follicle tracking.
Cervical mucus monitoring (CMM) is a prospective and inexpensive method to detect fertile window. It was found to be as good as or better than BBT or urinary LH monitoring to predict the day-specific probabilities of conception (Bigelow 2004). The cervical mucus is observed at the vulvar for its appearance and sensation. Type 1 and 2 are typically present at the beginning of menstrual cycle. They are associated with a dry (type 1) or damp (type 2) sensations at the vulva. Type 3 is typically thick, creamy and whitish or yellowish mucus with damp sensation. The type 4 cervical mucus is transparent, stretchy or elastic (raw egg white) with wet or slippery sensation. Intercourse at this period is associated with a high conception rate.
Hoeker et al., observed that CMM when applied consistently resulted in increased fecundability. It is more effective for timing of intercourse than the calendar method, as it allows identification of onset and duration of fertile window to be determined prospectively. It reduces the overall time to pregnancy.
CMM is a free, self-directed method used to detect fertile window prospectively. When applied consistently, it reduces the interval to conception and enhances fecundity.
Fecundity : Ability to conceive or to produce offspring
- Bigelow JL et al., Human Reprod 2004
- Brosens I et al., Sex Reprod Menopause 2006
- Evans-Hoeker E et al., Fert Steril 2013
- Wilcox AJ BMJ 1995