Understanding Cycle Characteristics

We now know from other literature only a small percentage of women ovulate exactly 14 days before the onset of menses. Baird et al. (1995) - study size 221, Lenton et al. (1984 a & b) - study sizes 327 and 293 cycles, respectively. This being the case even for women who usually experience a 28 day cycle length. In addition, as Wilcox et al. (2000) – study size 221 demonstrated, the fertile window falls entirely between cycle days 10 and 17 in only about 30% of women. Most women reach their fertile window earlier and some much later. This 'norm' continues to become less common as couples attempt to conceive later in life. So, earlier or later ovulation in a cycle is not necessarily a concern - but knowing when ovulation occurs is extremely important to maximise the chances of conception

Early Ovulation Wilcox et al. (2000) estimated that 2% of women were in their fertile window by the fourth day of their cycle and 17% by the seventh day (based on 213 women).

Late Ovulation An estimated 30% of OvuSense users have late ovulation - that is, an ovulation which occurs more than 65% of the way through a cycle. This estimate appears to be consistent with the findings of Wilcox et al. (2000) This pattern of a shortened follicular phase is more frequently identified in older women due to earlier dominant follicle selection - Klein et al. (2002) - study size 31 , and also correlates with a history of recurrent miscarriage - Jukic et al. (2007) - study size 201

Slow Rise A slow rise occurs in an estimated 5% of OvuSense users, and is characterised by a slow and steady increase in temperature over a number of days, rather than a steep rise over two to three days. A slow rise is generally related to Polycystic Ovarian Syndrome and/ or an indication of Polycystic Ovaries. However, it can also be a sign of Diminished Ovarian Reserve. A recurrent slow rise over 3 or more cycles without a previous diagnosis of either of these ovulatory issues would indicate the need for a formal diagnosis.

Short Luteal Phase A short luteal phase is deemed to be any ovulation that occurs 10 days or less before a subsequent onset of menstruation. This situation can occur with Polycystic Ovarian Syndrome but is not limited to that ovulatory issue alone. Short luteal phases are commonly seen at the extremes of reproductive life, at times of stress or due to other conditions such as thyroid disorders and stress. A short luteal phase in 2 or more cycles out of 3 would indicate a necessary treatment as women with a tendency to short luteal phase have a higher chance of miscarriage.