What Comes First - The Period Or The Egg?
Dear clients & friends,
Welcome to my twentieth issue of "The Good Fruit" newsletter by Natural Fruit FertilityCare Services.
In this last issue of my newsletter before I take a break to attend the AAFCP Annual Meeting conference in Philadelphia, PA in July and to work more on my certification paperwork, I would like to look at the question of "what comes first - the period or the egg?" Much like the "what came first - the chicken or the egg?" debate, the answer to this question isn't necessarily an obvious one.
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First, for definitions, the period (menstruation) is defined as "the shedding of the endometrial lining" that follows an "ovulatory event" (ovulation itself or an anovulatory unruptured follicle) and the period should have a variation of flow from crescendo-decrescendo (from lighter-heavier-lighter) or just decrescendo (from heavier-lighter) pattern. Ovulation is defined as "the release of the egg (ovum) from the ovary." While we often refer to the period as happening in the beginning of the cycle (starting on Cycle Day 1), it is actually the beginning of the next cycle, since it is defined as occurring when there is a decrease in the production of progesterone and estrogen by the corpus luteum (that is, after the corpus luteum degenerates, which starts at 8 days after ovulation and ends on average at 13 days after ovulation). Without the hormonal support, the endometrium degenerates and the lining is sloughed off as the menstrual period. Therefore, the normal menstrual flow (even in women who are anovulatory or oligoovulatory) occurs following ovulation or an ovulatory event. The period follows the production of progesterone by the corpus luteum.
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This concept makes sense from cycle-to-cycle, however there are some cases that may fall outside of this definition. One is for the first menstrual period (menarche) and another case is for the postpartum/breastfeeding woman who is not yet in cycles again and will start cycles either with ovulation first or a period first. Interestingly, cervical mucus discharge precedes the onset of the first menstrual period by several months. Cervical mucus is usually produced at the time when estrogen increases near ovulation, but this does not confirm for sure that ovulation is happening. Similarly, women who are breastfeeding may see either a continuous mucus discharge or a variable return of Peak-type mucus (VRPM) pattern that will eventually change as ovulation and menstruation return. For the postpartum/breastfeeding case, research has shown that if lactation is longer than 29 days in duration then 37.7 percent of women were observed to "ovulate" (confirmed by basal body temperature, which isn't proof of actual ovulation) prior to the onset of the first menstrual period. However, we can still assume that in this case, ovulation occurs prior to the first menstruation one out of three times. Otherwise, 43.4 percent of women first ovulated in their first cycle, 17.0 percent in their second cycle, and the remaining 1.8 percent in their third cycle. For women who breastfed for less than 28 days, 10.7 percent ovulated before their first menses, 71.4 percent ovulated for the first time during their first cycle, 14.3 percent in their second cycle, and the remaining 3.6 percent in their third cycle. So, most postpartum/breastfeeding women actually ovulate for the first time after their first period (during their first cycle). This is shown in the above photo's table. Similarly, in other situations such as post-abortion/miscarriage and post-Pill, ovulation may come sooner or later as the body adjusts to returning to cycles.
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So, what comes first - the period or the egg? It can actually be either one! 🙂
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Have a fruitful day!
Patricia Deshane, FCP
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