Severe period pain is often dismissed as a normal part of menstruation, yet for millions of women it can be a sign of endometriosis, a chronic condition that can cause persistent pelvic pain, infertility and major disruption to daily life.
The World Health Organization (WHO) estimates that about 10 per cent of women of reproductive age globally, or roughly 190 million people, live with endometriosis.
The condition can begin from the first menstrual period and continue through menopause. It occurs when tissue similar to the lining of the uterus grows outside the uterus, where it responds to reproductive hormones and can cause inflammation, bleeding, scarring and adhesions.
What is endometriosis?
Endometriosis mainly affects the pelvis but can also occur elsewhere, including the abdomen and, in some cases, the chest.
Consultant Obstetrician and Gynaecologist Dr Paul Koigi says the tissue outside the uterus responds to hormonal changes during the menstrual cycle.
Speaking on Radio Generation on Thursday, Koigi said the tissue can bleed during menstruation, triggering inflammation, scarring and adhesions.
“The problem is that every time you have a period, that tissue is also responding to the hormones and it can bleed. And when it bleeds, you get inflammation, you get scarring, you get adhesions, and that is where you start getting the pain,” Koigi said.
Symptoms vary between women and can include severe menstrual pain, chronic pelvic pain, heavy bleeding, bloating, nausea, painful sex and pain during bowel movements or urination.
Why is it difficult to diagnose?
One of the biggest challenges is that severe period pain is often treated as something women should simply endure.
WHO says endometriosis symptoms can be difficult to recognise, contributing to delays in diagnosis. The organisation estimates that diagnosis can take between four and 12 years.
Koigi says some women continue suffering because they have been taught that painful periods are a normal part of being a woman.
“There is this thing that we have been taught as women that, you know, periods are supposed to be painful. And so you have women who are literally collapsing every month, and they’re told, ‘That’s just how periods are,’” he said.
Pain that repeatedly interferes with school, work, sleep, relationships or other daily activities should prompt medical attention.
Endometriosis can affect fertility when inflammation, scarring and adhesions interfere with reproductive organs such as the ovaries and fallopian tubes.
WHO estimates that between 25 and 50 per cent of women experiencing infertility may have endometriosis.
However, the condition does not mean that every woman will experience fertility problems. Some women have pain and other symptoms without difficulty conceiving.
Endometriosis can also affect sexual health because of pain during intercourse.
A 2026 study involving women with confirmed endometriosis at a tertiary hospital in Kenya found that the condition had implications for sexual function and distress.
How common is it in Kenya?
The Ministry of Health reported a 4.6 per cent prevalence of endometriosis in Kenya in a 2024 response to Parliament.
The figure is consistent with a study conducted at Kenyatta National Hospital between 2018 and 2021. The study found histologically confirmed endometriosis in 4.6 per cent of indigenous African women aged 18 to 49 who were studied.
Kenya had an estimated 14.2 million women aged 15 to 49 in 2024, according to the Kenya National Bureau of Statistics.
If the 4.6 per cent figure were hypothetically applied to the entire population, it would amount to about 653,000 women.
However, this is only a mathematical extrapolation and is not an official estimate of the number of Kenyan women living with endometriosis because the 4.6 per cent prevalence came from a specific study population.
The Ministry told Parliament in 2024 that only two level-six public facilities, Kenyatta National Hospital and Moi Teaching and Referral Hospital, were treating endometriosis.
It also reported about 700 gynaecologists nationally but only five trained laparoscopic gynaecological surgeons, mainly based at national referral hospitals.
There is currently no definitive cure, but treatment can control symptoms and reduce the impact of the disease.
WHO lists painkillers, including non-steroidal anti-inflammatory drugs, and hormonal treatments such as combined hormonal contraceptives, progestins and GnRH medicines among treatment options.
The choice depends on the severity of symptoms, individual circumstances, possible side effects, cost, availability and whether a woman wants to become pregnant.
Surgery can be used in selected cases to remove endometriosis lesions, adhesions and scar tissue.
Laparoscopy involves inserting a camera and surgical instruments through small abdominal cuts. However, surgery is not necessary for every woman with suspected or confirmed endometriosis.
WHO says diagnosis and treatment can involve symptoms and imaging such as ultrasound or MRI, meaning surgery does not always have to come before treatment.
A hysterectomy may be considered in some severe cases when other treatments have failed and pregnancy is no longer desired. However, removing the uterus does not guarantee that the disease will be cured because endometriosis can occur outside the uterus and remain after surgery.
What does treatment cost?
The cost of care can create another barrier.
Kenyan lawmakers reported in 2024 that laparoscopic endometriosis surgery could cost between Sh350,000 and Sh1 million, depending on the circumstances.
The Social Health Insurance Fund tariff schedule separately lists Sh134,400 for endometriosis surgery under laparotomy.
This tariff should not automatically be taken as the total amount a patient will pay because consultations, investigations, medicines, hospitalisation, anaesthesia and follow-up may involve additional costs.
There is no single confirmed cause of endometriosis.
WHO says researchers are examining several possible factors, including immune-system changes and family history. A family history of the condition is associated with an increased risk.
Koigi has also raised concerns about possible environmental influences, including exposure to pesticides, plastics and other chemicals that may interfere with hormones.
However, these remain areas of research and should not be treated as proof that particular foods, cosmetics, pesticides, preservatives or genetically modified foods cause endometriosis.
“There are a lot of things that we are exposed to in our environment, whether it’s pesticides, whether it’s plastics, whether it’s some of these chemicals that we use, and there is increasing evidence that some of these things can interfere with our hormones,” Koigi said.
For women, severe or persistent menstrual pain, chronic pelvic pain, painful sex, painful bowel movements or urination, heavy bleeding or difficulty conceiving should not simply be accepted as normal.
Seeking medical assessment can help determine whether the symptoms are linked to endometriosis or another condition.
For Kenya, improving awareness, expanding specialist services, training more laparoscopic surgeons, strengthening diagnostic capacity and reducing treatment costs remain key areas in addressing the condition. The Ministry of Health has previously proposed specialised centres of excellence, additional training, more laparoscopic equipment, improved access to medicines and public-awareness campaigns