The menstrual cycle

How a cycle works

The average cycle is about 28 days, but anything between 21 and 35 days is considered normal, and month-to-month variation is common. It has three phases: the follicular phase (from the first day of bleeding to ovulation), ovulation, and the luteal phase, which is more consistent at 12 to 14 days. Ovulation therefore happens roughly 14 days before the next period — not 14 days after the last one.

That detail matters practically: in anyone with irregular cycles, ovulation is unpredictable, which is why fertility-awareness methods are less reliable in everyday use (see contraceptive methods).

Period pain: where normal ends

Mild cramping on the first day, relieved by simple painkillers, is common. Pain that makes you miss school or work, that does not respond to usual treatment, or that comes with pain during sex or bowel movements and severe fatigue is not normal and should raise the possibility of endometriosis.

Premenstrual symptoms

Irritability, breast tenderness, bloating, fatigue and low mood in the days before a period affect a large share of women to varying degrees. Regular exercise, less salt and alcohol, and adequate sleep often help. A severe form with major mood impact — premenstrual dysphoric disorder — is recognised and treatable: it deserves a consultation rather than resignation.

Heavy, absent or irregular periods

• Very heavy bleeding (changing protection hourly, large clots, fatigue) risks anaemia and should be investigated — fibroids, polyps, clotting disorders, or a copper coil.
• No periods for more than three months outside pregnancy also warrants investigation: polycystic ovary syndrome, thyroid problems, significant weight loss, intense exercise, major stress.
• Bleeding between periods or after sex should always be checked, if only to exclude a cervical cause.

Products and safety

Tampons, menstrual cups, period pants and reusable pads: no option is inherently better, but internal products must be changed or emptied regularly — at most every 6 to 8 hours for tampons, and never left in overnight — because of the rare but serious risk of toxic shock syndrome. High fever, vomiting or a rash during a period means removing the product and seeking urgent care.

On cost: period poverty is a documented problem, and the response differs sharply from one country to the next — some have made free provision a legal duty, others distribute in schools and public services, and many have removed sales tax on period products altogether. The position where you live is set out country by country below.

What differs between countries

The biology of the cycle is universal; the price of products, free provision, menstrual leave and the recognition of endometriosis are not. The table sums it up country by country; a full page covers those with enough to say, and otherwise the link leads to the country's contraception page, which shows where to find gynaecology care.

Country	Tax on period products	Free provision	Menstrual leave, endometriosis	Read more
European Union	Reduced or zero rate possible since 2022, at each state's choice	No common rule	No European text; Parliament resolutions on endometriosis	Full page
United Kingdom	0 % since 2021; period pants since 2024	All four nations: Scotland by law for anyone, England in schools and colleges	No leave; NICE guideline, specialist centres	Full page
Ireland	0 %, grandfathered	Funded programmes since 2021	No leave; HSE endometriosis framework 2023	Full page
United States	State by state: about half the states exempt	More than twenty states require products in public schools	No leave; FSA and HSA eligible since 2020	Full page
Canada	GST and provincial taxes removed in 2015	Federal workplaces since 2023; schools in several provinces	No leave; public system, long waits	Full page
Australia	GST removed in 2019	Government schools in every state and territory	No national leave; National Action Plan for Endometriosis, clinics since 2023	Full page
New Zealand	15 % GST, no exemption	All schools since 2021 (Ikura)	No leave; no national plan	Full page
India	0 % GST since 2018; one-rupee Suvidha pads	Several states in government schools	Leave in Bihar and Kerala only; no national law	Full page
Pakistan	Taxed at the standard rate	NGO programmes	No leave	Contraception and gynaecology: the country page
Singapore	9 % GST, no exemption	No national scheme	No leave	Contraception and gynaecology: the country page
Malaysia	Exempt since 2018	No national scheme	No leave	Full page
Philippines	12 % VAT; exemption bills pending	Free-provision bills pending	No leave	Contraception and gynaecology: the country page
Hong Kong	No sales tax	No public scheme; some universities	No leave	Contraception and gynaecology: the country page
South Africa	Pads zero-rated since April 2019	Quintile 1–3 public schools (Sanitary Dignity Programme)	No leave	Full page
Nigeria	Locally made pads exempt since 2020; imports taxed	State and NGO distributions	No leave	Full page
Kenya	VAT exempt since 2004	Public schools by law since 2017	No leave; MHM policy 2019–2030	Full page
Ghana	Locally produced pads zero-rated since 2024; imports taxed	National free programme for schoolgirls since 2025	No leave	Full page
Uganda	VAT exemption on pads	2016 promise of free pads in schools never generalised	No leave	Contraception and gynaecology: the country page
Zambia	No blanket exemption	Rural and peri-urban public schools since 2017	One paid day a month (Mother's Day) by law	Full page
Jamaica	No exemption known	NGO programmes	No leave	Contraception and gynaecology: the country page
Trinidad and Tobago	Zero-rated since 2016	No national scheme	No leave	Contraception and gynaecology: the country page

This topic is also covered for French-speaking countries · German-speaking countries.

South Africa

Sanitary pads benefit from a VAT zero rate, while public provision depends on the menstrual-dignity programmes serving eligible learners.