Optimizing Fertility Part II: Analyzing your BBT chart in the follicular phase

In Part I in this series of articles on fertility and traditional Chinese medicine, we discussed the how’s and why’s of basal body temperature (BBT) charting, an incredibly useful tool in identifying potential fertility challenges, and optimizing your reproductive health in preparation for pregnancy.

This following article focuses on BBT chart analysis of the follicular phase (Phase I), addressing some of the patterns that you are likely to see, with chart examples. 

The follicular phase begins on the first day of your period – this is counted as Day-1 of your cycle. This phase is a time of regeneration and replenishment, specifically of blood and yin. The endometrial lining is shedding, while the construction of a new lining is also beginning. Estrogen production increases, along with the growth of follicles and eggs within the ovary. Estrogen stimulates the production of fertile, cervical mucus; and influences the growth and quality of the new endometrial lining, which is vitally important for embryo implantation.

BBT should drop to its “base level” a day or two before the start of period. Base temperature, or starting temperature of the follicular phase, varies from woman to woman, and can also vary slightly from cycle to cycle. The average range for BBT throughout the follicular phase is 97.2° to 97.8°. See Figure 1.0 for an example of an optimal BBT.

If your follicular phase temperature tends to run too low (below 97.2°) (See Figure 1.1), this is a yang deficiency (specifically of the Spleen and Kidney organ systems). Often there are other constitutional symptoms, such as sensitivity to cold, fatigue, weight gain, and edema. The metabolism is typically slow, and sometimes there will be a Western diagnosis of hypothyroidism. 

The length of the follicular phase very often determines the length of the menstrual cycle. It reflects the length of time it takes for a follicle to grow in the ovary and release a mature egg. Unless there are symptoms that point to issues in the luteal phase, the period typically comes around fourteen days post-ovulation. For example, in a woman with a 21-day cycle, the follicular phase is likely seven days; in a woman with a 35-day cycle, the follicular phase is likely twenty-one days. (Note: It is possible for a luteal phase defect to shorten the length of the menstrual cycle – this will be discussed in a future article on Phase II. Your BBT chart will ultimately indicate how long your follicular phase is relative to your luteal phase.)

At the start of the follicular phase, which again begins on Day-1 of your period, the body is losing reserves that must be immediately replenished. The follicular phase is the time in your cycle when the body is working its hardest to replenish blood and yin. If your follicular phase is too long (See Figure 1.2) – longer than fourteen days – this is considered delayed ovulation. There is likely Kidney yin and/or blood deficiencies.

Qi stagnation (e.g., stress) is also a common, compounding factor with delayed ovulation – the smooth flow of qi is necessary for the transition from the follicular phase to the luteal phase, the transition from yin to yang – this is ovulation. 

If your follicular phase is consistently short (around nine or ten days) (See Figure 1.3), Kidney yin deficiency accompanied by heat is the most likely diagnosis. When yin is severely deficient, heat develops, and this heat can trigger premature ovulation. If eggs are released too soon, they will not be mature, and thus not conducive to fertilization, implantation, and a healthy pregnancy. 

If your follicular phase temperature is consistently too high (above 97.8°) (See Figure 1.4), there are other considerations. Temperature readings this high imply that there is internal heat that needs to be cleared. Internal heat tends to burn out the yin, leading to scanty or acidic cervical fluids, which are inhospitable to sperm. In addition, the endometrial lining may be too thin or dry to hold a pregnancy. 

If basal body temperature does not drop in the day or two before the onset of your period (See Figure 1.5), this indicates that there is an internal imbalance – yang is not effectively transforming into yin. This usually indicates the presence of “blood stagnation,” which can lead to the generation of internal heat. Sometimes there is a Western diagnosis of endometriosis. 

(Note: If your BBT remains elevated in the day or two before the expected onset of your period, and you skip your period – this very likely indicates pregnancy. See the next article on the luteal phase for discussion.)

Finally, BBT temperatures will fluctuate from day to day, this is normal, but if readings fluctuate more than .3°F, this is considered an unstable follicular phase (See Figure 1.6). Lack of sleep, alcohol consumption, or being sick, will all cause your temperature to spike, but if there is a pattern of unexplained sharp spikes and drops, there may be some Liver or Heart fire that needs to be quelled. An unstable follicular phase lends itself to unpredictable ovulation (i.e., irregular periods, potentially from a disorder somewhere along the hypothalamus-pituitary-ovary axis of the endocrine system, a system that is very vulnerable to the effects of stress). 

In the next article in this series on fertility and reproductive health, we will discuss ovulation in more depth, as well as the luteal phase and some of the patterns that you are likely to see, and ways in which acupuncture and herbal medicine can be used to optimize fertility in this second phase of your cycle.I hope you have found this series of articles on basal body temperature and chart analysis helpful.

If you are interested in learning more about how to optimize your fertility, you may be interested in my FREE online course on BBT charting. Learn more HERE.

Be Well,
Dr. Jules Bogdanski, DAOM L.Ac.