Pain is “an unpleasant sensory and emotional experience associated with actual or potential tissue damage, or described in terms of such damage…Pain is always subjective…It is unquestionably a sensation in a part or parts of the body, but it is also always unpleasant and therefore also an emotional experience.”
If you have chronic pain, you’re not alone. An estimated 25.3 million adults in the United States report severe, daily pain, significantly more women than men, while 55 percent of U.S. adults report at least some pain in the past three months. 1 Chronic pain is one of the most frequent reasons for physician visits and among the most common reasons for taking medication. 2
But there’s a gender gap when it comes to pain. Women have more frequent, longer lasting, and severe pain than men. 1 3 For instance, one national survey found that while about 16 percent of white men and 8 percent of black men reported severe pain, those numbers jumped to about 22 percent for white women and 11 percent for black women, respectively. 1
Women are also more likely to develop painful diseases, such as chronic fatigue syndrome, fibromyalgia, endometriosis, interstitial cystitis, vulvodynia, and temporomandibular disorders (TMJ) than men. They also report greater pain severity than men from certain conditions, such as cancer. 2 And women simply pay attention to pain from physical conditions more than men. They recognize when something is wrong. Men, on the other hand, have a tendency to ignore pain when they should pay attention to it.
Women also differ in their response to pain medications. They tend to need higher amounts of pain medications immediately after surgery, while men tend to use more pain relievers later in the recovery period. 4 Conversely, some medications (the partial kappa-opioid agonists, such as nalbuphine [Nubain] and pentazocine [Talwin]), can provide greater pain relief in women than men, although opioids such as morphine and codeine can lead to more nausea and vomiting in women than men. 5-7
The question that has plagued researchers for decades is: “Why?”
Part of it could be anatomy. Women have more nerve receptors than men, so they may be hard-wired to feel more pain. 8 Even something as seemingly minor as the thickness of your skin or the size of your body can affect pain perception. 9 Another reason may be that women are more likely to see a doctor than men, so maybe they’re just getting diagnosed more often.
Genetics also plays a role, affecting how long neurons that transmit pain signals to the brain survive and the strength of pain response, as well as pain tolerance, perception, and response to pain relievers. 2 But we also know that reproductive hormones—estrogen and progesterone in women, testosterone in men—play a role in these pain-related gender differences.
In women, the continual variation of hormonal levels through puberty, menstruation, pregnancy, and pre- and post-menopause contribute to these sex differences. For instance, prior to puberty, there are no significant differences in the development of painful conditions between boys and girls. 10 Afterward, the differences are dramatic, with women two- to six-times more likely to develop chronic pain conditions, such as headaches, irritable bowel syndrome, and fibromyalgia.11 There are also differences in pain levels and frequency after menopause.
Pain intensity tends to increase when estrogen levels are low and progesterone levels are high, as they are during the second half of the menstrual cycle, possibly because there are more naturally occurring “feel good” chemicals in the brain when estrogen levels are high. 5 12 You can imagine the evolutionary benefit to this: estrogen levels are highest during pregnancy and childbirth, thus providing some natural pain relief. Indeed, during pregnancy, when levels remain high and steady, studies indicate many pain conditions improve and pain sensitivity is lower. 10 11
Meanwhile, one interesting study found that women with TMJ reported less pain as pregnancy progressed (and estrogen levels rose) and more pain after surgical menopause (when estrogen levels plummet). 13 There’s even a name for it: pregnancy-induced analgesia. 10
In addition, reproductive hormones can also influence how well opioids and other pain relievers work. 14