Fertility Education Trust

guidelines to charting your fertility cycle, page 25 of 26

Complete Summary of Double-Check Rules Calendar / Mucus / Temperature

the infertile time before ovulation
(double-check of mucus and calendar)

Provided there was a temperature rise in the previous cycle,
the relatively infertile time begins on Day 1 of a true period
and ends on the night of the shortest cycle of the year minus 20 days,
or the last dry day^*, whichever comes FIRST.

the absolutely infertile time after ovulation begins on:
(double-check of mucus and temperature)

the 3^rd night after Peak Day (peak = last day of wet, slippery mucus)
and the 3^rd night (or 4^th ) of high temperature, whichever comes LATER
It ends on the last day of cycle - the day before the next period.

^*distinguishing seminal fluid from mucus in the phase after menstruation:

During this first phase of the cycle, it can be difficult to recognise DRY infertile days after the period because of the wetness caused by intercourse. After intercourse, seminal fluid leaks from the vagina over the next day and can look and feel like fertile mucus, causing a wet, slippery feeling at times. This is why the rules for intercourse are restrictive in the learning phase until the woman’s expertise increases.

To avoid confusion when looking for DRY days before the start of the fertile mucus symptom, it is recommended that you have intercourse at night time only in this first phase. Then, shortly afterwards, if you visit the toilet and express the residual seminal fluid from the vagina by bearing down, then blotting the area dry with tissue, you will more easily be able to judge on the next day whether you are still DRY, or whether genuine mucus is present. This practice enables couples to use consecutive DRY nights more confidently, if desired.

Once ovulation is over, (double check rule: peak + 3 days coinciding with 3 (or 4) high temperatures), there are no such restrictions on timing of intercourse. Since this post ovulation phase is absolutely infertile, once it is confirmed, intercourse can take place at any time.