You are pre-trying or in cycle one. You are not sure whether your morning coffee is fine, whether a Friday glass of wine ruins your chances, or whether you can still go to the pub with friends. This post gives you numbers on caffeine and alcohol TTC limits. The honest preconception thresholds are simpler than the internet suggests, and both partners are part of the conversation.
The short version, before we go through the evidence. Caffeine: aim for 200 mg per day or less, for both partners, from now through pregnancy. Alcohol: aim low pre-conception (well under the UK 14-unit weekly ceiling, ideally lower), and as close to zero as you can manage from a positive test forward. Heavy intake at either substance affects fecundability and, for alcohol, pregnancy outcomes. Moderate intake is mostly a personal call, with guidance leaning steadily more conservative on alcohol over the last decade.
Why caffeine and alcohol TTC limits apply to both partners
Most TTC content frames caffeine and alcohol as a question for the female partner. That is half the picture.
For the female partner, both caffeine and alcohol have evidence linking heavy intake to lower fecundability and higher miscarriage risk. Once pregnant, alcohol becomes a teratogenic exposure with no established safe lower threshold.3 5 For the male partner, heavy alcohol use suppresses LH and testosterone and impairs semen parameters.4 Heavy caffeine intake has been inconsistently associated with worse semen parameters. Spermatogenesis takes about 74 days, so what you drink now affects the sperm of three months from now.
The point: this is a couple-level decision, not a "what one partner does" decision. The pub night habit, the daily flat white habit, the after-work wine routine: they are all part of the picture.
Caffeine, and what the evidence shows
Pre-conception and natural conception
Multiple cohort studies and the 2017 Lyngsø meta-analysis suggest fecundability is similar at less than 200 mg per day of caffeine. That is roughly one strong cup of coffee or two cups of tea. Fecundability begins to decline above that threshold.1 Heavy intake of more than 500 mg per day is more consistently associated with lower fecundability. The plausible mechanisms include vasoconstriction, possible effects on tubal motility, and mild adverse effects on implantation in animal models. None are definitively established in humans.
Pregnancy and miscarriage
ACOG, NICE, and the NHS all consider 200 mg per day or less acceptable in pregnancy.5 Above that threshold, the signal becomes more consistent. Weng and colleagues' 2008 prospective cohort study suggested a dose-response between caffeine intake and miscarriage above roughly 200 mg per day. The strongest signal was above 300 to 400 mg.2 Not all subsequent studies replicated the effect at lower intakes, but the upper-bound advice has held.
The practical implication: if your daily intake is one or two mugs of coffee, you are within guidance. If it is four mugs plus tea plus a chocolate bar plus a fizzy drink, you are well above 400 mg per day and worth reducing.
What 200 mg actually looks like
The numbers vary by brewing strength and cup size, but rough working values:
- A standard mug of brewed filter coffee: around 80 to 100 mg.
- A Starbucks tall brewed coffee: around 120 to 180 mg.
- A shot of espresso: around 60 to 80 mg.
- A mug of black tea: around 40 to 50 mg.
- A mug of green tea: around 20 to 40 mg.
- A can of cola: around 30 to 40 mg.
- A standard energy drink: 80 to 160 mg.
- A square of dark chocolate (10 g): around 12 mg.
Two mugs of brewed coffee and a cup of tea is around 200 to 250 mg. An espresso-based flat white plus a cup of tea is around 100 to 130 mg. Energy drinks are the most underestimated source; one large can can be most of the daily budget.
Male partner caffeine
Moderate caffeine intake in the male partner is mostly fine. Very heavy intake of more than four mugs of strong coffee per day has been inconsistently linked to lower semen parameters in some cohorts. It is not a major lever compared with alcohol, smoking, sleep, BMI, and exercise. If sperm parameters are a concern, see foods to avoid for sperm health for the broader picture.
Alcohol, and what the evidence shows
Pre-conception, female partner
Heavy drinking, defined as more than 14 UK units per week or a binge pattern, is associated with lower fecundability and longer time-to-pregnancy. Mikkelsen and colleagues' 2016 Danish prospective cohort showed a dose-response effect for heavy intake.3 The relationship at lower intakes was weaker. The Nurses' Health Study II found similar associations at the upper end of drinking patterns.
Moderate intake at one to seven units per week has mixed and weaker associations. Some studies show neutral effects; some show small reductions. The honest position is that a single weekly glass of wine pre-conception is unlikely to materially affect fecundability for most people, but it is also not zero risk. The shift in guidance over the last decade has been toward "lower is safer" rather than "moderate is fine."
Pregnancy
There is no established safe lower threshold of alcohol in pregnancy. The UK Chief Medical Officers and NICE both recommend complete abstinence in pregnancy.6 Heavier intake correlates with fetal alcohol spectrum disorder, miscarriage, and low birth weight. The dose-response below those clear thresholds is uncertain enough that the guidance defaults to abstinence.
The practical implication for TTC: once a positive test could land in two weeks, "as close to zero as I can manage" becomes the default for most patients I see. That is a personal call, but it is the call most reasonable clinicians would make alongside their patient.
Male partner
Heavy alcohol intake suppresses luteinising hormone, lowers testosterone, and impairs semen parameters across several large datasets. The Ricci 2017 systematic review and meta-analysis on alcohol and semen quality showed reductions in volume, concentration, and morphology with daily alcohol intake.4 Recovery on cessation takes weeks to months, in line with the spermatogenesis cycle of about 74 days.
The conventional ceiling of 14 UK units per week with no binge pattern is a reasonable upper limit for the male partner during TTC. For the trying partner specifically, lower than that is better, and avoiding the weekend-binge pattern matters more than the weekly total.
What one UK alcohol unit looks like
One UK unit equals 10 ml or 8 g of pure alcohol. Working values:
- A 175 ml glass of 12 percent wine is about 2 units.
- A 250 ml large glass of 12 percent wine is about 3 units.
- A pint of 4 percent beer is about 2.3 units.
- A pint of 5 percent lager is about 2.8 units.
- A single 25 ml shot of 40 percent spirit is 1 unit.
- A 330 ml bottle of 5 percent beer is about 1.7 units.
The UK Chief Medical Officers' guidance of 14 units per week is roughly six medium glasses of wine, or six pints of mid-strength lager, spread across at least three days with no single binge.6 For TTC, my practical advice is to set a number below 14 that you can agree on as a couple in advance, so that it is not a fresh negotiation every Friday.
What about wine in the Mediterranean pattern
The original Mediterranean diet studies included moderate red wine with meals as part of the pattern.6 Modern preconception advice does not require it. The Mediterranean fertility benefit persists without alcohol, because the dietary pattern, not the wine, carries the evidence. If you enjoy a glass of wine, you do not have to give it up entirely for the diet to work. If you would rather not, you are not missing a fertility benefit. See Mediterranean diet and TTC.
Practical thresholds, couple-level
A pragmatic working table. These are defaults, not prescriptions. Personal history changes the call.
| Stage | Caffeine | Alcohol |
|---|---|---|
| Pre-conception, both partners | 200 mg/day or less each | 7 units/week or less each, no binge |
| Two-week wait | 200 mg/day or less | Minimise; many couples abstain |
| Confirmed pregnancy | 200 mg/day or less | Abstain |
| Male partner long-term TTC | 200-300 mg/day | 14 units/week or less, no binge |
If you have a history of recurrent miscarriage, alcohol dependence, or significant anxiety around these substances, the table does not apply cleanly. Speak to your clinician. The general framework is reasonable; the personalisation is the work.
What to do this week
Three small, concrete actions.
- Track your caffeine honestly for three days. Add up coffee, tea, fizzy drinks, energy drinks, and chocolate. Most people underestimate by a factor of two. Use the working values above.
- Decide your alcohol baseline for the trying window and agree it with your partner, so it is not a fresh decision every Friday. Couples who pre-agree do better than couples who renegotiate weekly.
- Try a switch. Decaf coffee after the second cup. Sparkling water with lime instead of the third gin and tonic. Alcohol-free beer is not a personal defeat; the supermarket shelf for it has tripled in the last five years for a reason.
When to involve your clinician
Three situations where this conversation belongs in the clinic, not on a forum:
- Alcohol dependence, or a pattern that does not respond to "cut down" advice. AUDIT screening and specialist support are appropriate. This is a health question regardless of TTC.
- Anxiety about caffeine or alcohol consumption that happened before you knew you were pregnant. "I had wine before I knew" stories are common and almost never need clinical alarm. Reassurance is the right answer. If the anxiety is taking over, that is itself worth raising.
- Recurrent pregnancy loss with possible alcohol exposure. The conversation needs to be frank and non-judgmental, and your clinician should lead it that way. If they do not, you are entitled to one who will.
For most couples, the caffeine and alcohol TTC question lands somewhere reasonable: a daily cup of coffee, an occasional glass of wine pre-conception, and a cleaner pattern from a positive test forward. That is the boring, evidence-aligned answer that I give most weeks in clinic.
What's next
- For the diet pattern that pairs with these limits, read Mediterranean diet and TTC.
- For the broader food-avoid list, read foods to avoid while TTC.
- For the male partner lifestyle context, see lifestyle habits that hurt sperm.
- For the broader diet evidence map, the pillar is the fertility diet.
- If you have just started tracking, read how to track BBT.
Sources
- Lyngsø J, Ramlau-Hansen CH, Bay B, Ingerslev HJ, Hulman A, Kesmodel US. Association between coffee or caffeine consumption and fecundity and fertility: a systematic review and dose-response meta-analysis. Clinical Epidemiology 2017;9:699-719. Link
- Weng X, Odouli R, Li DK. Maternal caffeine consumption during pregnancy and the risk of miscarriage: a prospective cohort study. American Journal of Obstetrics and Gynecology 2008;198(3):279.e1-8. Link
- Mikkelsen EM, Riis AH, Wise LA, et al. Alcohol consumption and fecundability: prospective Danish cohort study. BMJ 2016;354:i4262. Link
- Ricci E, Al Beitawi S, Cipriani S, et al. Semen quality and alcohol intake: a systematic review and meta-analysis. Reproductive BioMedicine Online 2017;34(1):38-47. Link
- American College of Obstetricians and Gynecologists. Committee Opinion No. 462: Moderate caffeine consumption during pregnancy. Obstetrics & Gynecology 2010;116:467-468. Link
- Department of Health (UK). UK Chief Medical Officers' Low Risk Drinking Guidelines. 2016. Link
- NHS. Drinking alcohol while pregnant. Link
Common questions
How much caffeine can you have while trying to conceive?
Aim for 200 mg per day or less, for both partners, from pre-conception through pregnancy. That is roughly one strong cup of coffee or two cups of tea. Fecundability begins to decline above that threshold, and heavy intake of more than 500 mg per day is more consistently linked to lower fecundability. ACOG, NICE, and the NHS all consider 200 mg per day or less acceptable in pregnancy.
What does 200 mg of caffeine actually look like?
Rough working values: a standard mug of brewed filter coffee is around 80 to 100 mg, a mug of black tea around 40 to 50 mg, a can of cola around 30 to 40 mg, and a standard energy drink 80 to 160 mg. Two mugs of brewed coffee and a cup of tea is around 200 to 250 mg. Energy drinks are the most underestimated source, as one large can can be most of the daily budget.
Do caffeine and alcohol limits apply to the male partner too?
Yes. Heavy alcohol use suppresses LH and testosterone and impairs semen parameters, and heavy caffeine intake has been inconsistently associated with worse semen parameters. Spermatogenesis takes about 74 days, so what you drink now affects the sperm of three months from now. This is a couple-level decision, not a question for one partner.
Is it safe to drink any alcohol while pregnant?
There is no established safe lower threshold of alcohol in pregnancy. The UK Chief Medical Officers and NICE both recommend complete abstinence in pregnancy. Heavier intake correlates with fetal alcohol spectrum disorder, miscarriage, and low birth weight, and the dose-response below those thresholds is uncertain enough that guidance defaults to abstinence.
How much alcohol is too much when trying to conceive?
Heavy drinking, defined as more than 14 UK units per week or a binge pattern, is associated with lower fecundability and longer time-to-pregnancy. For the female partner, aim well under that 14-unit ceiling, ideally lower, and as close to zero as you can manage from a positive test forward. For the male partner during TTC, 14 units per week with no binge pattern is a reasonable upper limit, and lower is better.