The event around which so much fertility planning revolves around is menstruation i.e. the period. Yet, uterine bleeding can happen at other times and the menstrual period can occur with some variation.

For this post, we will focus on uterine bleeding in the setting of an anatomically normal uterus, in an otherwise healthy woman. Numerous hormonal and structural abnormalities can lead to abnormal bleeding such as thyroid disease, fibroids, polyps, etc. Let’s only focus on uterine bleeding when there are no such abnormalities.

What is considered unusual?

The most common form of unusual uterine bleeding is an early or late period. A period happens when the remnant of a follicle stops producing progesterone and the blood levels of this hormone drop. For better or for worse, there is a widespread thought that a period must be spot-on each month. It actually does not need to. In fact, a normal cycle can vary between 21 to 35 days long in a group of otherwise healthy women. Furthermore, for any given woman, it is normal for the start of a period to vary by about 3-4 days each month.

Additionally, the length of a woman’s period will change with age with the least variation being seen between the ages of 40-42. Excess weight will also lead to somewhat more variation. Hence, it is completely normal to have a period be off by several days month-to-month. Only when a period is shorter than 21 days, longer than 35 days or a women has gone more than 90 days without a period should an evaluation be done.

Bleeding in the middle of a cycle

Now we arrive at another unusual form of uterine bleeding, bleeding in the middle of a cycle. Most often this is bleeding at the time of ovulation. Like with a period, ovulatory bleeding happens when a hormone’s level drops, this time estrogen. In one Danish study, 23-60% of women experienced some form of bleeding around the time of ovulation. It ranged from noticeable spotting/staining to microscopic amounts of blood, only seen with careful analysis.

Clearly, having a spot-on period helps with timing of fertility treatments and with quality of life in general. Nonetheless, when bleeding happens somewhat early or late or somewhat in the middle of a cycle – this should be no cause for worry. It is simply the result of small variations in a woman’s own hormonal clock and does not affect her fertility future.