PCOS (now called PMOS) symptom: cycle
Irregular periods with PCOS: why it happens and what helps
Late, rare or missing reglaregla: Period or menstruation. is the most common reason Filipinas get checked for PCOS (now called PMOS). Here is why it happens, when it is a concern, and what helps.
Editorially reviewed on October 29, 2026. [TODO: medical reviewer] How we review
Quick answer
In PCOS, the ovaries do not release an egg regularly, so periods come late, rarely or not at all. The 2023 Guideline calls cycles irregular when they are under 21 or over 35 days, or fewer than 8 a year (from 3 years after your first period).
If you have gone 3 months without a period and are not pregnant, see a doctor. Long gaps let the womb lining build up. The pill, a progestin, metformin and lifestyle support can all help.
What counts as irregular?
Cycles are counted from the first day of one period to the first day of the next. The 2023 International Guideline defines irregular cycles by time since your first period (Rec 1.1.1):
| Time since first period | Irregular means |
|---|---|
| First year | Irregular cycles are normal while the body matures |
| 1 to 3 years | Still settling; the guideline uses wider cut-offs, so ask your doctor |
| 3 years onward | Cycles under 21 or over 35 days, or fewer than 8 a year |
Bakit irregular ang regla ko?
A regular period is the end of a chain: a follicle grows, releases an egg (ovulation), and about two weeks later the womb lining sheds. In PCOS, higher androgensandrogens: Hormones like testosterone. Everyone has them; in PCOS they are often higher. and insulin resistanceinsulin resistance: When the body needs more insulin than usual to keep blood sugar steady. stop follicles from finishing that growth. Many small follicles stall, no egg is released (anovulationanovulation: Not releasing an egg in a cycle. The main reason periods become irregular in PCOS.), and the period does not arrive on time.
High insulin and androgens
Signals to the ovary are off
Follicles stall
Many small follicles, no mature egg
No ovulation
The cycle has no clear end point
Late or missing period
The lining keeps building
That is why the new name, polyendocrine metabolic ovarian syndrome, mentions metabolism: insulin is part of why ovulation goes off track. It is not caused by stress alone or by anything you did wrong.
Ilang buwan walang regla, delikado ba?
One of the most upvoted posts on r/PCOSPhilippines (151 upvotes) is a warning from someone who shared her experience with a ruptured cyst after ignoring months without a period, because she was used to irregular cycles. Her advice was blunt: “Huwag niyo akong gayahin.”
Here is the medical side, without the panic:
- The lining keeps growing. Without ovulation, the womb lining is exposed to estrogen without the progesterone that normally makes it shed. Over time, a thick lining increases the risk of endometrial cancer.
- Treatment protects it. A combined pill or a progestin brings on regular bleeds and keeps the lining thin. This is one of the main reasons doctors treat irregular periods even when you are not trying to get pregnant.
- Three months is the line. If you have gone 3 months or more without a period and you are not pregnant, book a consult. You do not need to wait until something hurts.
Get care now if you have
Severe or sudden pelvic pain, very heavy bleeding, fainting, or a positive pregnancy test with pain or bleeding. Go to an emergency room.
Is it PCOS or something else?
Irregular periods have many causes. Before diagnosing PCOS, doctors rule out:
- Pregnancy. Always first. Take a pregnancy test if you have had sex, even if your cycles are usually irregular. PCOS is not contraception.
- Thyroid problems. Checked with a TSH blood test.
- High prolactin. Checked with a prolactin blood test.
- Other causes: big weight changes, intense exercise, illness, some medicines, and the first years after your first period.
PCOS is diagnosed when you have two of three features: irregular ovulation, high androgens (acne, chin hair, scalp thinning, or a blood test), and polycystic ovaries or a high AMH. If you have irregular cycles plus androgen signs, you may not need an ultrasound at all (Rec 1.4.9). See how PCOS is diagnosed, or start with the self-check.
What helps
The right option depends on your goal: regular bleeds and lining protection, metabolic health, or getting pregnant.
- Combined pillModerate evidenceGives a regular, predictable bleed and protects the womb lining. Could be recommended for irregular cycles; no type is preferred, and the 35 mcg CPA/EE formula (Diane-35, Althea) should be second-line (Rec 4.2.4, 4.2.5). Prescription only.₱540 per box₱943 per boxLearn more
- Progestin to protect the liningModerate evidenceFor people who cannot or do not want to take the combined pill, a doctor may use a progestin to bring on a bleed and protect the lining. Prescription only.
- MetforminModerate evidenceCan help cycles in some people, especially with insulin resistance. Considered in adults with BMI 25 or higher (Rec 4.3.1). Prescription only.₱2 per tablet₱18.25 per tabletLearn more
- Healthy eating and movementModerate evidenceRecommended for everyone with PCOS, at any weight. No specific diet or exercise is better (Rec 3.1.1). It supports metabolic health, which affects ovulation.Learn more
- Letrozole, if you want to get pregnantStrong evidenceIf your goal is pregnancy, the plan changes: letrozole is the first-line medicine to help you ovulate (Rec 5.3.1). Prescription only.₱107 per tabletLearn more
- InositolLimited evidenceA food supplement with no approved therapeutic claims in the Philippines. The guideline says it could be considered, with limited clinical benefits (Rec 4.7.1).₱26.50 per sachetLearn more
Prices checked October 2026. Prices at Philippine drugstores and labs change often; confirm before you go.
This guide is for information. Talk to a doctor before starting or changing any treatment.
When to see a doctor
- You have gone 3 months or more without a period and you are not pregnant.
- Your cycles are regularly longer than 35 days, or you have fewer than 8 periods a year.
- Irregular periods come with acne, chin or body hair, scalp thinning, or dark patches on your neck.
- You are trying to get pregnant and your cycles are irregular. You do not need to wait a full year.
- Bleeding is very heavy, lasts more than a week, or happens between periods.
A basic check (OB consult plus ultrasound) costs about ₱1,500 to ₱2,500. A transvaginal ultrasound at a government hospital costs ₱450 to ₱750 per scan. Not sexually active? Ask for a transrectal ultrasoundtransrectal ultrasound: A pelvic scan through the rectum, offered to people who are not sexually active. or an AMH test. See the full cost guide.
Example
“My periods come every 2 to 3 months.”
- Pregnancy test, TSH, prolactin
- 75 g OGTT
- Pill or metformin
Track your cycles
The most useful thing you can bring to a consult is a record of your period start dates. Our free PCOS cycle tracker flags gaps over 35 days and fewer than 8 cycles a year, nudges you after 3 months without a period, and prints a one-page summary for your doctor. Everything stays on your phone.
- How PCOS is diagnosedTests in order, and what you can skip.
- What it costsEvery peso figure, with sources.
- Pills for PCOSDiane vs Althea vs Yaz, explained.
- Metformin for PCOSGeneric vs brand, side effects and myths.
- All symptomsAcne, hair, weight, mood and more.
Frequently asked questions
Ilang buwan walang regla, delikado ba?
If you have gone 3 months or more without a period and you are not pregnant, see a doctor. Long gaps let the womb lining build up, which over time raises the risk of endometrial cancer. Treatment with a pill or progestin protects the lining.
Delayed ako pero negative ang PT. PCOS ba ito?
It could be, but stress, thyroid problems, high prolactin, big weight changes, intense exercise and some medicines can also delay periods. If your periods are often late, or you have missed 3 months, see an OB-GYN.
How long is a normal cycle?
From 3 years after your first period, the 2023 Guideline counts cycles under 21 days or over 35 days, or fewer than 8 periods a year, as irregular. In the first year after your first period, irregular cycles are normal.
May PCOS pero regular ang regla. Possible ba?
Yes. Diagnosis needs two of three features, so you can have PCOS with regular periods if you have high androgens plus polycystic ovaries or a high AMH.
Hindi ba ako mabubuntis kasi irregular ako?
You can still get pregnant. Irregular cycles mean you ovulate less often, not never. Use contraception if you do not want a baby, and see a doctor if you are trying to conceive.
Does the pill fix PCOS periods?
The pill gives a regular bleed and protects the lining while you take it. It does not change the underlying PCOS, so cycles may become irregular again after you stop.
Is PMOS the same as PCOS?
Yes. PMOS (polyendocrine metabolic ovarian syndrome) is the new name for PCOS, announced in The Lancet on 12 May 2026. It is the same condition with the same diagnosis and the same treatments. Both names will be used until the 2028 International Guideline update.
Sources
- Recommendations from the 2023 International Evidence-based Guideline for the Assessment and Management of Polycystic Ovary Syndrome. Teede HJ et al., Fertility and Sterility (co-publication), 2023.
- Summary of the International Evidence-based Guideline for PCOS 2023. Monash University / Monash IVF, 2023.
- PMOS: symptoms and causes. Mayo Clinic, 2026.
- Polyendocrine metabolic ovarian syndrome (PMOS). NHS, 2026.
- Mabahala ka kung ilang buwan ka na hindi nagkakaroon ng menstruation (thread). r/PCOSPhilippines, 2026.
- Transvaginal ultrasound cost in the Philippines. ClinicFinderPH, 2026.
- Althea product listing (cyproterone acetate 2 mg, ethinylestradiol 35 mcg). Watsons Philippines, 29 October 2026.
- Diabetes medicine prices in the Philippines. ClinicFinderPH, August 2026.