Headaches and Hormone Therapy - Is it Safe?
Making sense of your migraines
Headaches are very common affecting ~48% of the population. Migraine, tension-type (TTH), and cluster headaches comprise 98% of all headaches. The World Health Organization (WHO) ranks migraine headaches as the second leading cause of disability in the world, particularly in women under the age of 50, with an estimated global prevalence of 15%.
Women experience headaches 3x more often than men which may be attributed to the hormonal fluctuations of the menstrual cycle, pregnancy, and menopause among other physiologic reasons.
It’s important to characterize headaches accurately as different types of headaches have different levels of risk of stroke and other complications. This is particularly important when considering hormonal contraception and menopausal hormone therapy (HT).
The risks and benefits associated with the use of menopausal hormone therapy (MHT) have been the subject of intense debate since the Women’s Health Initiative (WHI) study discontinued the estrogen/progestin arm of the study due to what was described as a “significant increase in the risk of breast cancer” in 2002. Since this time, providers and patients alike have expressed apprehension around the use of HT for this and various other reasons. Similarly, because some types of headaches impart a greater risk of stroke, this has also contributed to a sometimes overly cautious approach to MHT use.
The different subtypes and diagnostic criteria of headaches can lead to some confusion surrounding which types of headaches carry an increased risk of stroke versus those that do not. Migraine headaches, in particular, raise cause for concern as this type of headache is associated with an increased risk of stroke and other thrombotic (blood clot formation) events. But does that mean that hormone therapy and hormonal contraception are non-starters for anyone who suffers from migraine headaches? Absolutely not. As with any intervention, the decision needs to be informed by, a thoughtful, individualized risk/benefit assessment, rather than a “path of least resistance” approach where every woman who suffers from migraine headaches is painted with a broad brush stroke.
Today’s post is intended to empower you with the knowledge that you need to have that thoughtful discussion with your provider about the risks and benefits of hormonal treatments in the setting of your headache history so that you can make the decisions that are right for you!
What is a Migraine Headache?
Migraine headache is a complex, genetically influenced, neurovascular disorder characterized by episodes of moderate-severe headaches, most often unilateral (one-sided) and often associated with nausea and light sensitivity.
The International Headache Society characterizes migraine headache into 3 subtypes:
Migraine without aura (75% of migraine headaches)
Recurrent attack lasting 4-72 hours
Unilateral and pulsating
Moderate to severe intensity
Aggravated by physical activity
Nausea
Light and sound sensitivity
Migraine with aura
Recurrent, fully reversible attacks lasting minutes
Unilateral
Associated with one or more of the following: Visual, sensory, speech/language, motor, and/or visual disturbance followed by headache and migraine symptoms.
Chronic migraine
Occurs on 15 or more days in a month for more than 3 months
Migraine features noted on 8 or more days in a month
What “Triggers” a Migraine Headache?
There is a long list of potential migraine triggers, however, the most common ones occurring in more than 50% of migraine sufferers include:
Stress (80%)
Hormonal changes during menstruation, ovulation, and pregnancy (65%)
Skipped meals (57%)
Weather changes (53%)
Excessive or insufficient sleep (50%)
Stroke Risk and Migraine Headache
It is widely known that Migraine headaches are associated with an increased risk of stroke. But how high is this risk, exactly? Are different types of Migraine headaches associated with higher stroke risk than others? The answers to these questions are very important to begin the risk/benefit assessment.
A note about understanding “Risk”:
“Relative risk” is when the incidence of an outcome of interest is compared between two scenarios (Outcome A is 10x greater than outcome B). “Absolute risk” is the actual frequency of the outcome of interest in the population (Outcome A occurs in 10 in every 10,000 people. Outcome B occurs in 1 in every 10,000 people).
So, if the use of MED A is associated with a “10x greater risk of X”, that sounds pretty horrible…. but if that risk translates into 10 cases of X in 10,0000 people, the risk of X in those taking MED A is 10/10,000 = 0.1%. Not so horrible! This may be a reasonable risk to take when your quality of life is impacted by your symptoms. This is one of the areas where the WHI got into trouble in their narrative surrounding breast cancer risk and HT.
A consensus statement published by the European Headache Federation (EHF) and the European Society for Contraception and Reproductive Health (ESC) describes the absolute risk of stroke in women aged 20-44 suffering from migraine headaches and using hormonal contraception in a meta-analysis of 63 studies. The risk of stroke in the various study populations is summarized as follows:
The baseline stroke risk in the female population aged 20-44, (-) hormones, (-) migraine history is 2.5/100,000.
(+) hormonal contraception (-) migraine history is 6.3/100,000
(-) hormonal contraception (+) migraine WITH AURA is 5.9/100,000
(+) hormonal contraception (+) migraine WITH AURA is 36.9/100,000
(-) hormonal contraception (+) migraine WITHOUT AURA is 4.0/100,000
(+) hormonal contraception (+) migrainen WIHTOUT AURA is 25.4/100,000
It was also noted in this study that higher doses of ethinyl estradiol (the estrogen component of the hormonal contraceptive) are associated with higher stroke risk.
Unfortunately, there is no similar study that investigates these risks specifically in menopausal women with migraine headaches using MHT. However, it is reasonable to expect that these trends likely continue into menopause. However, one very important difference (besides age) is that MHT has much lower estrogen exposure than what is found in typical hormonal contraceptive pills and there are also bioidentical estradiol alternatives not commonly found in typical hormonal contraceptive pills. To determine whether these different doses and formulations impact stroke risk would need further investigation.
Approach to HT Use in Menopausal Women with Migraine Headaches
If you are a menopausal woman who suffers from migraine headaches and is considering HT, here are some important points to raise with your provider so that you can make a decision that is right for you.
Is MHT effective for the symptoms or health concerns that you are experiencing (i.e. are the expected benefits of HT great enough to outweigh potential risks?)
Have you been diagnosed with migraine headaches by a knowledgeable provider? Avoid self-diagnosis as characterizing headaches is complex and mis-characterization of your headache may lead to an inaccurate risk assessment.
If you have been diagnosed with migraine headaches, It is important to know if your headaches are classified as WITH or WITHOUT aura. According to the data, stroke risk is higher when aura is present.
Do you have any other risk factors for stroke? Obesity, smoking, high blood pressure, diabetes, chronic inflammation, and genetic predisposition are among the most common risk factors for stroke. The presence of other stroke risk factors in addition to a migraine headache history are additive and are important for risk assessment when considering further additional stroke risk incurred when using HT.
Expert consensus suggests that transdermal HT may carry a lower stroke risk than oral HT.
Estrogen dose matters for stroke risk. Use the lowest possible dose of HT that is effective for symptom relief.
If multiple stroke risk factors exist, consider progestin-only HT such as a progesterone IUD or micronized progesterone as well as non-hormonal remedies that may be appropriate for symptom management.
What if I used to have migraine headaches before menopause but no longer do now that I am menopausal? Again, data is sparse on this topic, but my personal opinion is that the underlying neurovascular physiology that led to the migraines in reproductive life still exists post-menopause. There may be fewer hormonal triggers and thus fewer headaches once menstrual cycles cease, however, the existing underlying physiology of the nerves and blood vessels may still pose an increased stroke risk.
It is important to appreciate the complexity of characterizing headaches accurately which can be very challenging for the generalist provider. If you are considering hormone therapy and are uncertain of your headache status/stroke risk profile, a neurologist or headache specialist can help ensure an accurate diagnosis. Consulting with a specialist may also lend some assurance to your generalist provider who is uncomfortable prescribing hormone therapy to patients with migraine headaches.
REFERENCES
Considerations for hormonal therapy in migraine patients: a critical review of current practice Romy van Lohuizena. Paungarttnerb J et al. Expert Review of Neurotherapeutics 2024, VOL. 24, NO. 1, 55–76.
Myocardial infarction, stroke, and cardiovascular mortality among migraine patients: a systematic review and meta-analysis. CYH N et al. J Neurol. 2022 May;269(5):2346–2358.
Migraine and cardiovascular disease: systematic review and meta-analysis. Schürks M et al. BMJ. 2009 Oct 27;339 (oct27 1):b3914.
Hormonal contraceptives and risk of ischemic stroke in women with migraine: a consensus statement from the European Headache Federation (EHF) and the European Society of Contraception and Reproductive Health (ESC). Sacco S et al. J Headache Pain. 2017 Oct 30;18(1):108.
Migraine Headache: Stat Pearls NIH Library of Medicine; Pescador MA et al. Treasure Island (FL): StatPearls Publishing; Jan 2024.
Housekeeping…..
I am so excited to announce my latest collaboration with Feisty with the debut of a 4-part series for the Feisty Women’s Performance Podcast called “Hormonal”. The awesome and amazing Selene Yeager and I team up to bring you the ESSENTIALS of what women of all ages should know about how hormones impact athletic performance, how to identify when something goes wrong, and how to work WITH your physiology rather than against it to achieve your performance potential.
Subscribe now to the Feisty Women’s Performance Podcast and gear up for Episode 1 which drops on April 15th!
