Pre-Pregnancy Medication Stop Calculator — PCOS / PMOS
Planning a pregnancy with PCOS involves careful management of your current medications. Some common PCOS treatments — particularly spironolactone — are teratogenic and must be stopped months before conception. Others, like metformin, may be continued based on medical advice. And some, like folic acid, must be started well before pregnancy.
This calculator generates a personalised checklist with action dates calculated from your target conception date. It is a tool to support your medical consultation — bring it to your appointment to discuss with your doctor or gynaecologist.
My pregnancy plan
Enter the date from which you wish to conceive.
Why plan medication changes before pregnancy?
Pre-conception medication planning is a frequently underestimated step in the PCOS pregnancy journey. Several medications used to manage PCOS symptoms have significant implications for the developing foetus — some are teratogenic, others require dose adjustment during pregnancy.
A pre-conception consultation with your doctor enables you to:
- Stop teratogenic medications with sufficient lead time
- Identify alternative treatments to maintain hormonal and metabolic control during the transition period
- Start recommended supplements (folic acid, vitamin D) at the right doses and at the right time
- Optimise your metabolic baseline before conception (blood sugar, BMI, blood pressure)
PCOS medications and pregnancy: case by case
Spironolactone — stop 3 months before
Spironolactone is an aldosterone antagonist with potent anti-androgenic activity, used in PCOS for hyperandrogenism (acne, hirsutism). It is formally contraindicated in pregnancy: it can cause feminisation of male foetuses (hypospadias, pseudohermaphroditism) by blocking androgen receptors during foetal genital development.
The medication's SmPC recommends a 3-month (12-week) washout after stopping before conceiving. Effective contraception must be maintained throughout this period. Discuss with your doctor alternatives to manage hyperandrogenism during the transition (inositol, certain combined pills if not yet trying to conceive, etc.).
Metformin — no mandatory washout
Metformin is widely used in PCOS for insulin resistance. It is not considered teratogenic based on available evidence. Meta-analyses (Tang et al., 2012) suggest it may reduce early miscarriage risk in women with PCOS and hyperinsulinism. It is classified as FDA pregnancy category B and is permitted during pregnancy in NICE guidelines for appropriate patients. The decision to continue through the first trimester or stop at conception belongs to your doctor based on your specific profile.
Hormonal contraception — variable ovulation return
Stopping hormonal contraception is often the first step in a pregnancy plan. The return of ovulation varies considerably between women and by contraceptive type. With combined oestrogen-progestogen pills, most women regain ovulation within the first cycle, but a delay of 1–3 months is common. In PCOS, cycles may remain irregular for several months after stopping, since they were already disrupted before contraception. This window can be used to introduce ovulation-inducing treatments if needed, in consultation with your specialist.
Folic acid — start 3 months before
Folic acid is the essential supplement for any planned pregnancy. In PCOS, insulin resistance can interfere with folate metabolism, making early supplementation particularly important. NICE guidelines and NHS recommendations advise starting folic acid at least 1 month before conception, ideally 3 months before. The standard dose is 400 mcg/day (continuing through the first trimester). A dose of 5 mg/day is recommended where there is a personal or family history of neural tube defects. Your doctor or midwife will confirm the appropriate dose.
Clinical evidence and guidelines
The washout periods in this calculator are based on official guidelines and medical literature available as of 2026.
- NICE (UK) 2023 — Fertility problems assessment and treatment. Spironolactone: teratogenic, stop before conception with effective contraception. Folic acid: 400 mcg before conception and through first trimester.
- ACOG / SMFM 2023 — Pre-conception care in PCOS. Metformin: may be continued in T1 based on individual risk. Ovulation inducers: used during conception cycles, stopped at confirmation.
- Tang T et al. (2012) — Metformin for non-diabetic women with polycystic ovary syndrome and infertility. Cochrane Database Systematic Review.
- FDA Drug Safety Categories — Spironolactone: Category X (contraindicated in pregnancy). Metformin: Category B.
- NHS Guidelines 2024 — Vitamin D: 10 mcg (400 IU)/day recommended throughout pregnancy and breastfeeding.
Preparing your pre-conception medical appointment
A dedicated pre-conception consultation is recommended for all women with PCOS planning a pregnancy. Here is what is useful to prepare:
- Full list of current medications (name, dose, duration of use)
- Your most recent blood results (insulin, glucose, testosterone, AMH)
- Approximate target conception date
- History of miscarriages or previous fertility treatments
- Family history of birth defects or inherited conditions
You can use our PCOS doctor letter template to prepare your consultation and communicate effectively with your medical team.
Frequently asked questions
Why does spironolactone require a 3-month washout before pregnancy?
Spironolactone is teratogenic: it can cause foetal genital development abnormalities by blocking androgen receptors. A 3-month washout is required for complete drug elimination and return of normal hormonal activity. This recommendation is present in the medication's SmPC and in international endocrinological guidelines.
Can I continue metformin during the first trimester of pregnancy?
Metformin is not considered teratogenic. Several studies suggest it may reduce early miscarriage risk in PCOS. Whether to continue or stop at confirmed conception is your doctor's decision, based on your individual clinical profile. NHS guidance permits continuation for appropriate patients.
How long after stopping the pill can you get pregnant with PCOS?
Most women regain ovulation within 1–3 months. With PCOS, cycles may remain irregular for several months after stopping. Absence of ovulation after 3 months warrants specialist consultation.
When should I start folic acid if I have PCOS and want to get pregnant?
Ideally 3 months before conception (minimum 1 month before). NICE recommends 400 mcg/day. A higher dose of 5 mg may be prescribed with a family history of neural tube defects. Early supplementation is especially important in PCOS due to potential folate metabolism interference from insulin resistance.
Do clomiphene or letrozole need a washout period before trying to conceive?
No — these are ovulation-inducing medications used to help achieve pregnancy. They are taken during conception cycles and stopped at pregnancy confirmation. Their short half-lives mean no pre-conception washout is required.