Pre-Conception Checklist: What to Do Before You Start Trying

If you have decided you are going to start trying in the next three to six months, you are at the highest-use point of the whole process. The three months before "go time" is the only window where the changes you make today actually show up in the egg and sperm that meet on cycle one. This post is the doctor-led version of that checklist, for both partners.

I wrote this because almost every couple I see in clinic has been piecing it together from twelve Instagram reels, a forum thread, and a friend's recommendation. There is also a much quieter problem underneath that. Men preconception health is rarely covered properly anywhere, and partners often skip preconception care because nobody invites them in. About half of subfertility involves a male-side factor in some way, yet most preconception advice is written as though only one body is involved.⁴ I want to fix that here.

Why three months, not three weeks

Sperm and eggs are not produced overnight. Spermatogenesis, the full process of making mature sperm from a precursor cell, takes around 74 days inside the testis, followed by roughly another 14 days of transit through the epididymis where sperm acquire motility.³ That is close to three months from the moment a cell starts becoming a sperm to the moment it leaves the body. So when a partner stops smoking today, the semen analysis three months from now is the first one that reflects it. The semen analysis three weeks from now still reflects the smoker.

The egg side has a similar timeline. The dominant follicle that will ovulate in this cycle was selected roughly 85 to 90 days earlier, when it was a small antral follicle being nudged toward maturation. That means today's folic acid, today's blood sugar, today's thyroid status are all influencing the follicle that will ovulate three months from now. This is the Gougeon model of folliculogenesis, and it is the reason guideline bodies talk in three-month windows rather than three-week windows.²

This shapes everything that follows. The recommendations below are not a thirty-day reset. They are a three-month preparation block, and they apply to both of you.

For the person carrying the pregnancy

Supplements with strong evidence

The single best-evidenced intervention in preconception care is folic acid. The US Preventive Services Task Force reaffirmed in 2023 that all people who can become pregnant should take 400 to 800 micrograms of folic acid daily, starting at least one month before conception and continuing through the first trimester.¹ NICE in the UK uses the same baseline of 400 micrograms.² The reason is not subtle: adequate periconceptional folate reduces the risk of neural tube defects by roughly 70%, and the neural tube closes before most people know they are pregnant.

A higher dose of 5 milligrams per day is recommended if any of the following apply: BMI of 30 or above, pre-existing diabetes, epilepsy on certain anticonvulsants such as carbamazepine or valproate, a previous pregnancy affected by a neural tube defect, sickle cell disease, or thalassaemia.² In those situations the standard 400 microgram dose is not enough, and the prescription needs to come from a GP.

Beyond folate, the evidence-backed list is shorter than the supplement aisle suggests. Vitamin D 10 micrograms (400 IU) daily is recommended year round in the UK because sunlight exposure is unreliable for most of the year.² Iodine at around 150 micrograms per day matters for foetal brain development, and many prenatals include it. A comprehensive prenatal that contains B12 and choline (around 450 milligrams) covers most of the rest of what matters. I tell people in clinic to think of the prenatal as a floor, not a ceiling. The harder layer of supplements, things like CoQ10 and inositol that come up later in PCOS or diminished ovarian reserve conversations, sit in a different category and belong to a different stage of the journey.

Baseline health review

If you do one thing this month, book a "planning a pregnancy" appointment with your GP. It is a specific appointment type with a specific agenda, and it is one of the few times in adult medicine when the doctor's job is to look forward, not backward.

The agenda I want from that visit is straightforward. First, a medication review for teratogenicity. Drugs that need to be addressed before conception, not after, include isotretinoin for acne, methotrexate, sodium valproate, ACE inhibitors and angiotensin receptor blockers for blood pressure, warfarin, and certain antiepileptics. None of these should be stopped abruptly without a clinician involved, and many of them have safer pregnancy alternatives that need a switch-over window. Every week in clinic I see someone at eight weeks pregnant still on an ACE inhibitor or isotretinoin, and that conversation should have happened three months earlier.

Second, vaccination status. Confirm immunity to rubella, varicella, and pertussis. MMR and varicella are live vaccines and need to be given before conception, not during pregnancy. The flu vaccine in season and the COVID booster are safe in pregnancy but easier to take care of before. Cervical screening should be up to date.

Third, baseline measurements. Blood pressure and weight should be recorded so any deviation later in pregnancy is comparable to a real starting point. BMI in the 19 to 30 range is associated with shorter time to pregnancy and lower rates of gestational diabetes and pre-eclampsia, but the goal is not a number on a scale, it is the trajectory in the months before TTC.

Conditions to optimise before TTC, not during

Some chronic conditions have specific pre-conception targets that matter much more than most people are told.

For pre-existing diabetes, NICE recommends an HbA1c target below 48 mmol/mol (6.5%) before conception where this is achievable without problematic hypoglycaemia.⁵ Higher HbA1c at conception is associated with congenital malformations, miscarriage, and stillbirth in a dose-dependent way. This is one of the few preconception conversations where the timing of pregnancy is genuinely up for negotiation. Bringing HbA1c down before conception changes outcomes more than almost anything that happens later.

For hypothyroidism, the American Thyroid Association suggests TSH below 2.5 mIU/L before conception in people already on levothyroxine, with a planned increase in dose once pregnant.⁶ Untreated or undertreated hypothyroidism is associated with miscarriage and impaired neurodevelopment, and the fix is often as simple as a thyroid blood test and a small dose adjustment.

For hypertension, ACE inhibitors and ARBs need to be switched off before conception. Labetalol, nifedipine, and methyldopa are the usual pregnancy-safe options, and that switch is a GP visit, not an emergency.

For mental health, do not stop antidepressants at the first hint of a pregnancy plan. Most SSRIs are reasonably safe to continue, sertraline in particular. Untreated depression in pregnancy has its own risks. The right time to review is now, calmly, with the GP or psychiatrist, not at six weeks pregnant when you are panicking about whether to swallow your next pill.

If you have PCOS already on the radar, weight, metformin, and inositol all sit in the next stage of the journey rather than this one. The preconception version of PCOS care is: confirm the diagnosis, document cycle pattern over two or three months, get an HbA1c and lipids, and walk into TTC with that picture in hand.

Lifestyle

Smoking is the single biggest modifiable lifestyle factor. ASRM's 2018 committee opinion is unambiguous: smoking accelerates ovarian ageing, lowers IVF live-birth rates, and increases miscarriage risk.⁸ Vaping is not a safe substitute. The honest framing in clinic is that stopping now, in this preparation window, is one of the few things you can do that measurably changes outcomes on both sides of the couple.

On alcohol, no safe amount has been established for pregnancy, and the first trimester window is the most sensitive. Reducing intake now reduces the chance of an unrecognised exposure between conception and a positive test. Caffeine under 200 milligrams per day is supported by ACOG, which is roughly one moderate coffee. Cannabis and other recreational drugs should be stopped before TTC.

Sleep matters more than the supplement aisle would suggest. Aim for seven hours or more. Shift work and chronic circadian disruption are associated with longer time to pregnancy. None of this is a moral position. It is just where the evidence is strongest.

Dental and screening

A dental check before pregnancy is not a vanity item. Periodontitis, the gum disease that follows untreated gingivitis, is associated with adverse pregnancy outcomes including preterm birth, and the time to address it is before, not during. STI screening, including chlamydia, is worth doing because chlamydia is often asymptomatic and is one of the leading causes of tubal damage and ectopic pregnancy. Genetic carrier screening is a conversation to have with the GP if there is family history, consanguinity, or ancestry that carries specific risks (Tay-Sachs, sickle cell, thalassaemia, cystic fibrosis).

For the partner, men's preconception health

I want this section to be findable by the partner directly, because in clinic the conversation about men preconception health usually starts a year too late, often after a negative semen analysis at the twelve-month workup. The preparation window for the male side is the same three months, and the use on outcomes is real.

Why this matters

NICE's fertility guideline puts a male factor in around 30% of subfertility cases on its own, and a combined male and female contribution in another 20%.⁴ That means in roughly half of couples who do not conceive in twelve months, something on the male side is part of the picture. None of this is talked about until it has to be, which is the worst time to start.

If you are reading this as the male partner, the most useful thing you can do in the next twelve weeks is treat your body as a sperm-producing system that is on a 74-day timer. What you do today shows up around three months from now.

Lifestyle changes with evidence

The boring stuff matters more than the supplements. Smoking and vaping both have clear dose-response effects on sperm motility, concentration, and DNA fragmentation. Stopping now means the semen sample in three months looks measurably different from the one today. Alcohol intake under 14 units per week, with several alcohol-free days, is the threshold that most guidelines settle on. Heavy drinking impairs spermatogenesis. Recreational drug use, particularly anabolic steroids, will shut down sperm production entirely, and the recovery curve after stopping can be six to twelve months.

BMI between 20 and 25 is associated with the best sperm parameters and the highest live-birth rates. Obese BMI is linked to reduced sperm concentration, lower motility, and lower fertilisation rates. This is not aesthetic. It is hormonal: adipose tissue converts testosterone to oestrogen through aromatase, which suppresses the pituitary signal back to the testes.

Heat is the underappreciated factor. Testes sit outside the body for a reason. Daily hot tubs and saunas, laptops resting directly on the lap for hours, and tight underwear all raise scrotal temperature enough to affect sperm production. None of these need lifelong avoidance, but cutting back during the preparation window is reasonable. Long-distance cycling has been studied; weekend riding is fine, but very high-volume cyclists may want to pay attention to saddle pressure and heat.

Sleep, stress, and regular moderate exercise round out the list. None of these are mystical. They are inputs to a system on a three-month timer.

Supplements with reasonable evidence

A male preconception multivitamin including zinc, selenium, vitamins C and E, folate, and CoQ10 is a reasonable addition. The 2022 Cochrane review on antioxidants for male subfertility concluded that antioxidant supplementation may improve live-birth and pregnancy rates in subfertile couples, with low to moderate quality of evidence.⁷ The honest framing is that this is a low-risk addition, not a cure. The Cochrane authors were careful to note that the evidence base is heterogeneous and that we still do not know which specific antioxidant, at which dose, makes the biggest difference.

What is not a substitute for any of this: a women's prenatal taken by the male partner. Formulations differ. He needs a male preconception formula, or at minimum a high-quality multivitamin with the components above.

When the partner should ask for a semen analysis

Before TTC begins, a semen analysis is only indicated if there is a specific clinical reason. That short list includes prior testicular trauma, mumps orchitis after puberty, varicocele, undescended testicle history (cryptorchidism), prior chemotherapy or pelvic radiotherapy, or a known fertility issue from a previous relationship.

Otherwise, the routine threshold for a semen analysis is six to twelve months of regular unprotected intercourse without conception, in line with NICE.⁴ If TTC begins at age 35 or older on the female side, the threshold drops to six months. The detail of what a semen analysis looks at, and what the WHO 6th edition reference values mean, belongs to the diagnosis stage rather than this one.

Both of you, together

A few items only make sense at the couple level rather than the individual level.

Lubricants matter more than people realise. Most over-the-counter lubricants, including the most common high-street brands, are sperm-toxic at fertility-relevant concentrations.⁵ If lubricant is needed, use a fertility-friendly product or, if appropriate, plain mineral oil. ASRM lists the products that have been formally tested.

Intercourse pattern is the other big one. The highest-yield pattern, supported by Wilcox's NEJM paper and ASRM's optimising natural fertility opinion, is intercourse every one to two days throughout the cycle, not abstinence saving up for ovulation.⁴ "Saving up" lowers pregnancy rates rather than raises them, because sperm parameters do not improve with longer abstinence past about two days, and the fertile window is wider and earlier than most people think. The full mechanics of the fertile window sit in a separate post on cycle physiology.

Stopping contraception is its own conversation. There is no need to wait a few cycles before trying after stopping the pill, the implant, the coil, or the patch. Fertility returns quickly for most methods, but ovulation may take a cycle or two to reassert a regular pattern. Depo-Provera is the one exception worth flagging, because return of ovulation can take six to twelve months after the last injection.

For same-sex couples planning with donor sperm, or single people using a known or unknown donor, most of this still applies to the person carrying the pregnancy. The male preconception section is relevant when the donor is known and willing, but the practicalities of donor sperm preparation are a different conversation.

What to time and what to track

A few dates are worth writing down explicitly, because they are the inputs to every future decision.

1. The first day of your last menstrual period after stopping contraception. This becomes your cycle day 1 reference.
2. The date you started folic acid. This is the anchor for "have I had at least one month of folate before conception."
3. The date you started any lifestyle change (stopped smoking, switched off ACE inhibitor, started prenatal). These anchor the three-month window for gamete quality.
4. A 12-month timer if you are under 35, or a 6-month timer if you are 35 or older. This is the threshold for a fertility workup if conception has not occurred.⁴

Tracking cycle length for two or three cycles before the "first month of trying" is one of the most useful things you can do, because it tells you whether your cycles are regular, which tells you whether ovulation is happening, which tells you what cycle day to time intercourse around.

Red flags, see a GP before, not after, you start trying

There are situations where waiting twelve months is the wrong default and an earlier conversation is the right one. See a GP before starting TTC, or very early in the process, if any of the following apply:

• Cycles consistently shorter than 21 days or longer than 35 days, or absent for more than three months
• A known diagnosis of PCOS, endometriosis, uterine fibroids, or prior pelvic surgery
• Age 35 or older with any of the above
• Recurrent miscarriage history, defined as two or more consecutive losses
• A partner with a known fertility issue, prior testicular surgery, or relevant medical history

In any of these situations, the earlier conversation is not a panic conversation. It is just a triage one. The fertility workup, if needed, is the same workup whether it starts at month one or month twelve, but starting earlier shortens the timeline by exactly that much.

A realistic 12-week plan

If the list above feels like a lot, the plan below is the same content compressed into a working timeline.

1. Week 1: Book the GP "planning a pregnancy" appointment. Start a prenatal containing 400 micrograms of folic acid (or 5 milligrams if a higher-dose indication applies). The male partner starts a male-formula multivitamin including zinc, selenium, and antioxidants. Stop smoking and vaping on both sides.
2. Week 4: GP appointment complete. Medication review done. Vaccinations updated. Any chronic conditions (diabetes, thyroid, hypertension, mental health) reviewed and adjusted. Cervical screening up to date.
3. Week 8: At least one full cycle logged so you have a sense of cycle length. Lifestyle changes in progress. STI screen and dental check done. Alcohol reduced. Caffeine under 200 mg per day.
4. Week 12: Ready to start trying. Folic acid has been on board for nearly three months. The male partner has completed one full sperm-production cycle on the new lifestyle. Cycle pattern is documented. The first three months of habit change are now reflected in gamete quality.

Twelve weeks is short enough to be motivating, and long enough that the biology has actually moved.

What's next

• If you have completed the preparation window and want to think about exact timing: when to start trying, age, health, and timing
• If you want a realistic sense of how long this typically takes: how long it usually takes to get pregnant
• If your cycles are irregular or absent and you are not sure preconception advice applies: when to see a fertility doctor
• If a deeper supplement and lifestyle protocol is the next step, particularly for PCOS or known male factor: CoQ10, prenatals, and supplements before TTC

Sources

1. US Preventive Services Task Force, Barry MJ, Nicholson WK, et al. Folic acid supplementation to prevent neural tube defects: US Preventive Services Task Force Reaffirmation Recommendation Statement. JAMA 2023;330(5):454-459. https://www.uspreventiveservicestaskforce.org/uspstf/recommendation/folic-acid-for-the-prevention-of-neural-tube-defects-preventive-medication
2. National Institute for Health and Care Excellence. Antenatal care. NICE Guideline NG201. London: NICE; 2021. https://www.nice.org.uk/guidance/ng201
3. World Health Organization. WHO Laboratory Manual for the Examination and Processing of Human Semen, 6th edition. Geneva: WHO; 2021. https://www.who.int/publications/i/item/9789240030787
4. National Institute for Health and Care Excellence. Fertility problems: assessment and treatment. NICE Clinical Guideline CG156. 2013, updated 2017. https://www.nice.org.uk/guidance/cg156
5. National Institute for Health and Care Excellence. Diabetes in pregnancy: management from preconception to the postnatal period. NICE Guideline NG3. 2015, updated 2020. https://www.nice.org.uk/guidance/ng3
6. Alexander EK, Pearce EN, Brent GA, et al. 2017 Guidelines of the American Thyroid Association for the diagnosis and management of thyroid disease during pregnancy and the postpartum. Thyroid 2017;27(3):315-389. https://www.liebertpub.com/doi/10.1089/thy.2016.0457
7. de Ligny W, Smits RM, Mackenzie-Proctor R, et al. Antioxidants for male subfertility. Cochrane Database of Systematic Reviews 2022, Issue 5, CD007411. https://www.cochranelibrary.com/cdsr/doi/10.1002/14651858.CD007411.pub5/full
8. Practice Committee of the American Society for Reproductive Medicine. Smoking and infertility: a committee opinion. Fertility and Sterility 2018;110(4):611-618. https://www.asrm.org/practice-guidance/practice-committee-documents/smoking-and-infertility-a-committee-opinion-2018/