When the unthinkable happens and a woman of childbearing age receives a cancer diagnosis, one of the countless questions she may have is whether she will be able to have any (or any more) children after undergoing chemotherapy. A 2012 study called infertility “one of the main long-term consequences of combination chemotherapy for lymphoma, leukemias, and other malignancies in young women” [1] (emphasis added). And a 2019 study of Taiwanese women who underwent chemotherapy for breast cancer regrettably found that “Women with breast cancer lacked knowledge about infertility and underestimated the possibility of infertility” [2].
What is known (and unknown) about the possibility of fertility returning after completion of chemotherapy? For answers to this question and others, and at the recommendation of FACTS founder Dr. Marguerite Duane, Natural Womanhood turned to Dr. Thomas Bouchard. Dr. Bouchard is a Marquette Method medical consultant, and an associate professor at the University of Calgary. He has significant experience in both research and in-person clinical practice caring for family medicine and obstetrics patients, and has first-hand experience with a patient who successfully monitored her return to fertility post-chemotherapy treatment..
Why does chemotherapy make a woman (at least temporarily) infertile?
According to the National Cancer Institute, “Chemotherapy (especially alkylating agents) can affect the ovaries, causing them to stop releasing eggs and estrogen.” Another way chemo makes women infertile is by directly damaging their eggs. We’re all familiar with the hair loss that accompanies cancer treatment, which is because chemo drugs work to kill rapidly dividing cells, including cancer cells and (unfortunately) cells in the hair roots and oocytes (eggs)–even if they’re healthy. Chemo-induced infertility may be temporary or permanent, but is more likely to be permanent in women who are closer to menopause than it is in younger women.
For reasons we will explain below, the various effects of chemotherapy on the reproductive system can render data from traditional biomarkers inaccurate (cervical mucus changes) or unusable (temperature readings, qualitative urinary hormone readings) during and immediately after treatment. However, as we will also discuss, there is hope that quantitative urinary hormone monitors may provide an opportunity for women to monitor and track their return to fertility after discontinuing chemotherapy treatment.
Why can’t a woman on chemo use traditional cervical mucus or basal body temperature observations to track her fertility?
Throughout the interview with Natural Womanhood, Dr. Bouchard referenced a case study of a Marquette Method user who was diagnosed with breast cancer and started chemotherapy.
Why mucus-based methods are unreliable for women on chemo
As we cover in greater detail here, estrogen is primarily produced by the ovaries, and rising estrogen levels in the days immediately preceding ovulation stimulate production of clear, stretchy, egg white-appearing cervical mucus (EWCM). Women utilizing mucus-based FAMs track EWCM observations to know when they are fertile. But as Dr. Bouchard explained, the woman in the case study’s estrogen levels never rose, and remained consistently low while she was on chemotherapy, thus making mucus changes based on estrogen changes unreliable.
Why you can’t use temperature observations to determine fertility during chemo
In addition to monitoring the mucus sign, symptothermal methods also utilize basal body temperature (BBT) observations to determine that ovulation has occurred, since the progesterone rise after ovulation causes a noticeable rise in BBT. Unfortunately, these methods also won’t work in women undergoing chemo, because as Dr. Bouchard explained, the lack of ovulation experienced by a woman undergoing chemo means there will be no progesterone rise, and “she’s not going to get any temperature shift.”
Can you successfully use hormonal methods while undergoing chemo?
So, if symptom-based biomarkers like cervical mucus and BBT are unreliable (or nonexistent) for monitoring fertility while undergoing chemo, what about methods that utilize urinary hormone monitoring? Women may wonder, in particular, if the Marquette Method can be successfully utilized during chemotherapy to monitor their return to fertility.
Why qualitative hormonal monitors like the ClearBlue fertility monitor are unreliable during and immediately after stopping chemo
In order to identify whether she was fertile or not while on chemo, and then to determine when her fertility returned after stopping chemo, the patient in Dr. Bouchard’s case study originally used the ClearBlue fertility monitor (CBFM), which tests urinary hormone levels of luteinizing hormone (LH) and provides ‘low,’ ‘high,’ or ‘peak’ fertility readings.
But the woman in the case study had “high” readings every day she tested using the CBFM, which could never naturally occur, and was a direct result of the chemotherapy. Normally, LH surges immediately before ovulation, and then rapidly decreases again; the CBFM tests estrogen and LH in the urine to identify when this happens. But CBFMs give only a qualitative reading (low, high or peak) for LH levels.
Dr. Bouchard shared, “When you’re talking about traditional methods that use mucus or temperature, you’re not going to be able to get accurate results mainly because when estrogen and LH levels are fluctuating – and in the case study the woman’s LH levels were consistently high- there is no pattern of fertility that can be discerned.” He continued, “LH is something that surges in a very narrow window for a few days and then goes right back down…persistently high LH over many days is not what happens physiologically in a normal cycle, so it was clearly related to the chemotherapy.”
Why you may want to consider using a quantitative hormonal monitor (i.e., the Mira monitor) instead
When the chemotherapy case study patient consulted Dr. Bouchard, he recommended that she switch to the Mira quantitative urinary hormone monitor because it gives actual numbers of both estrogen and LH levels, rather than qualitative “low,” “high,” or “peak” readings. Dr. Bouchard previously conducted research published last fall (the full text of which was provided to Natural Womanhood for review), proving that the Mira monitor can accurately and reliably determine the fertile window in normal, healthy women, when compared to the CBFM (which was itself previously validated by research) [3][4].
After consulting with Dr. Bouchard, the patient began utilizing the Mira monitor. To use the monitor to track her fertility, she used a personalized protocol developed by Dr. Bouchard, which blended Mira monitor readings with a version of a question from the Two-Day Method, which required the patient to ask herself the daily question “Was my estrogen level over 100 (ng/mL) yesterday or today?” If the answer was ‘yes,’ she would abstain. If the level was under 100, “that was an available day [for intercourse].” Says Dr. Bouchard: “That protocol did work for her, and she was able to follow that all the way through until she stopped chemo and started cycling again.”
Of the patient’s experience with the monitor, Dr. Bouchard noted “to see that persistently high LH tells you that she’s not ovulatory, the ovulatory mechanism is disrupted.” But, he added, “when she stopped the chemotherapeutic agents, her LH levels started to drop, and her estrogen started to rise, and within a month she resumed a normal physiologic state where she was able to ovulate and we were able to see a normal cycle and a normal period after that.”
Dr. Bouchard observed, “This is the first case of a woman using chemotherapy that has been tracked with quantitative hormones that I’m aware of. There’s never been the ability before to track the hormones in a quantitative way to get the data that we got from this particular case. So this is brand-new information.” (Dr. Bouchard recommended any woman who wants to use fertility awareness after receiving a cancer diagnosis requiring chemo contact a Marquette Method instructor, who can in turn get in touch with him.)
What factors influence whether fertility will return?
While Dr. Bouchard’s case study is encouraging, as we mentioned above, not all women will regain their fertility post-chemotherapy. Unfortunately, for some women, chemo will render them permanently infertile.
The two biggest factors impacting whether a woman’s fertility will return after stopping chemotherapy are her age (the younger she is, the more likely her fertility will return) and the type of chemotherapy she received (more on types associated with long-term infertility is here). Rather than anticipating infertility due to chemo, Dr. Bouchard believes “You would expect fertility to return, depending on [the woman’s] age. However, he notes, ”“people who are not aware of their natural fertility are not necessarily tracking or following this closely.”
Additionally, he pointed out, women receive a cocktail or combination of multiple drugs for chemotherapy; chemo is not one specific drug. As a result, every woman is different, and thus different women’s chances of fertility returning will vary. “This is not something where we can generalize about chemo, it really depends on the chemo agent they’re using.”
Of note, while the woman in the case study experienced a return of fertility within one month after chemo ended, women are often counseled to wait a minimum of six months after stopping chemo before trying to conceive to ensure that any eggs damaged by the chemo medications are no longer in the body. Like the woman in the case study, women seeking to avoid pregnancy after chemo could conceivably work with their healthcare provider to determine when they could have intercourse based on Mira monitor (or other monitor that gives quantitative- specific numbers rather than a ‘high’ or ‘low’ result) readings.
When it comes to chemo’s effects on fertility, more research is needed
In addition to its usefulness for women undergoing or post-chemotherapy, Dr. Bouchard sees great value in having the advanced hormonal analysis offered by quantitative data monitors like Mira. Women who may especially benefit from the more granular detail offered by quantitative monitors may include: postpartum women, women who generally have low LH such that the CBFM doesn’t detect the levels, women who are approaching menopause, and women who have PCOS, to name a few.
Of course, the case report discussed here is only the starting point. “Going forward, case reports and case series in NFP are really important to share. The more data we can collect, the more we can share ideas” to benefit women, says Dr. Bouchard. He values what he calls “crowd-sourced research;” “there are so many NFP users who are collecting data, and having a way to get the data from the users to the researcher to put things together in a case series is what we need to do. And that requires crosstalk from methods, and users, and people interested in this topic.”
Note: Dr. Bouchard reported no financial interests to disclose.
References:
[1] Blumenfeld, Zeev. “Chemotherapy and fertility.” Best practice & research. Clinical obstetrics & gynaecology vol. 26, no. 3 (2012): pp. 379-90. doi:10.1016/j.bpobgyn.2011.11.008 [2] Huang, Sheng-Miauh et al. “Infertility-related knowledge in childbearing-age women with breast cancer after chemotherapy.” International journal of nursing practice vol. 25, no. 5 (2019): e12765. doi:10.1111/ijn.12765 [3] Bouchard, Thomas P et al. “Quantitative versus qualitative estrogen and luteinizing hormone testing for personal fertility monitoring.” Expert review of molecular diagnostics vol. 21, no. 12 (2021): pp. 1349-60. doi:10.1080/14737159.2021.2000393 [4] Behre, H M et al. “Prediction of ovulation by urinary hormone measurements with the home use ClearPlan Fertility Monitor: comparison with transvaginal ultrasound scans and serum hormone measurements.” Human reproduction (Oxford, England) vol. 15, no. 12 (2000): pp. 2478-82. doi:10.1093/humrep/15.12.2478Additional Reading:
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