How to Get Pregnant: A Doctor’s Evidence-Based Guide to Fertility, Timing and Preparation
- Dr Natalie Hutchins
- Oct 29
- 7 min read
By Dr Natalie Hutchins
If you’ve decided you’re ready to start trying for a baby, it can feel both exciting and daunting. Many of us spend years actively avoiding pregnancy, only to realise when the time comes that we’ve never been taught how conception actually works or how to give ourselves the best chance.
The reassuring truth is that most couples conceive naturally within a year of regular, unprotected sex. But fertility is influenced by biology, age, lifestyle, and health in both partners. Understanding these factors lets you approach conception confidently, not fearfully.
Understanding Fertility: The Basics for Women and Men
Female fertility
Women are born with all their eggs; about one to two million at birth. By puberty, that number falls to roughly 400 000, and only around 400 are ever ovulated.Egg quantity and quality both decline with age: slowly through the 20s, more noticeably after 32, and steeply after 35. By 40, the chance of natural conception in any given month is about 5–10%; by 45, it’s below 2%.
Research also shows ethnic variation in ovarian ageing. On average, South Asian women experience menopause one to two years earlier than Caucasian women, and may see a steeper drop in ovarian reserve in their late 20s and early 30s. Black women often show higher AMH (a marker of egg quantity) when younger, but a sharper decline later and slightly earlier menopause overall. It’s important to remember that these are averages though and not predictions, but they highlight why personalised fertility discussions matter.
Male fertility
Men make new sperm continuously, yet sperm quality, particularly DNA integrity and motility also declines with age and lifestyle. Obesity, smoking, alcohol, sleep deprivation, poor diet and even heat from tight clothing can all reduce fertility.Encouragingly, sperm renew about every 74 days, so positive lifestyle changes can improve results within a few months.
Timing Sex: Why the Simplest Advice Is Still the Best
Because sperm survive up to five days inside the female reproductive tract and an egg lives about 24 hours after ovulation, the most fertile window is the five days before ovulation and the day of ovulation itself.
If your cycle is regular (21–35 days), the best advice is to have sex every two to three days after menstruation ends. This ensures sperm are always present when ovulation happens.
Ovulation kits and apps can help some couples, but they often add stress without improving pregnancy rates. For most, relaxed, regular intimacy beats precision timing.
The Role of Supplements: What You Really Need
Despite the marketing noise, only a few supplements have solid evidence behind them.
Folic acid is essential. Take 400 micrograms daily for at least three months before conception and through the first trimester. It reduces the risk of neural-tube defects by up to 70%. Even if you carry the MTHFR gene variant, folic acid remains the recommended form.
Some women need a higher dose (5 mg daily) prescribed by their doctor. This includes those who:
Have diabetes or epilepsy (especially if on sodium valproate or carbamazepine)
Have a BMI ≥ 30
Have a family or personal history of neural-tube defects
Have thalassaemia, sickle-cell disease, or other haemoglobinopathies
Take certain anti-folate medications (e.g. methotrexate)
Have malabsorption (e.g. coeliac disease, inflammatory bowel disease)
Vitamin D (10 micrograms / 400 IU daily) helps bone health, immune regulation and possibly implantation. Deficiency is common, even in sunny climates.
Iron, calcium, and iodine may be advisable for women with restricted diets (e.g. vegan, lactose-free) or known deficiencies.
Beyond this, there’s little evidence that extra supplements or “fertility blends” improve conception outcomes and so your main focus should be on eating as well as you can.
Preparing for Pregnancy: Why a Pre-Conception Appointment Matters
A pre-pregnancy consultation is one of the most valuable, but often most overlooked, steps when planning to conceive. It’s a holistic health review to optimise conditions for conception and pregnancy.
Who benefits most
Everyone can benefit, but it’s especially important if you:
Are over 35
Have irregular or painful periods, PCOS, or endometriosis
Live with a chronic condition such as diabetes, thyroid disease, hypertension, epilepsy, or autoimmune illness
Take long-term medications, including mental-health medications such as antidepressants, mood stabilisers, or antipsychotics (some need dose adjustments or safer alternatives before conception)
Have a mental-health diagnosis such as depression, bipolar disorder, anxiety, or an eating disorder pregnancy can alter medication needs and relapse risk
Have had recurrent miscarriages
Have had pelvic surgery, chemotherapy or radiotherapy
Your partner has known sperm or hormonal issues.
What’s checked
A doctor or midwife will typically:
Review your medical, surgical, family and reproductive history.
Take blood pressure, BMI, and basic labs (thyroid, glucose, vitamin D or anaemia screen if indicated).
Discuss medications and whether any should be changed pre-pregnancy.
Offer STI screening (for chlamydia, gonorrhoea, HIV, syphilis, hepatitis B/C) even if you have no symptoms. This is because untreated infections can cause scarring, miscarriage or complications in pregnancy.
Review vaccinations. Ideally, you should be protected against rubella, varicella (chickenpox), hepatitis B, influenza, COVID-19 and whooping cough (pertussis) before pregnancy. Live vaccines (like rubella or varicella) should be given at least one month before trying to conceive.
Confirm your cervical-screening (Pap smear) status is up to date. Cervical screening is not performed in pregnancy unless there’s an abnormal result, so it’s best to check before you start trying.
Offer pre-pregnancy counselling on genetic screening, particularly for couples of certain ethnic backgrounds (e.g. thalassaemia carrier testing in South and Southeast Asian populations).
For men, this is also an opportunity to discuss lifestyle, review medications (especially testosterone or anabolic steroids, which can suppress sperm), and arrange a semen analysis if indicated.
Coming Off Contraception: What to Expect
When you decide to start trying, you don’t usually need to wait for months after stopping contraception as fertility often returns faster than people think.
Combined oral contraceptive pill, patch or vaginal ring: Ovulation typically resumes within two to four weeks of stopping. Some women experience a “withdrawal bleed” followed by their first true period about four to six weeks later. Cycles can be slightly irregular for a few months as hormones readjust, but most regain fertility within three months.
Progestogen-only pill (mini-pill): Because it leaves the body quickly, ovulation may return within days to weeks once you stop, especially if you have regular cycles on it.
Depo-Provera injection: This is the one exception where fertility can take time to recover. It may take 6–12 months (and occasionally up to 18) after the last injection before ovulation and regular periods return, though long-term fertility is unaffected.
Hormonal intrauterine system (IUS/Mirena) or contraceptive implant: Fertility generally returns almost immediately after removal and many women can conceive in the first cycle.
Copper IUD: Because it contains no hormones, fertility returns straight away once removed.
Barrier methods (condoms, diaphragms): obviously, fertility resumes immediately once they’re no longer used.
There’s no medical need to wait for several “normal” cycles before trying to conceive. You can start as soon as you feel ready; the main reason to wait until after your first natural period is simply for easier pregnancy dating.
If cycles remain absent more than three months after stopping hormonal contraception (apart from the Depo injection), it’s worth checking in with your doctor to rule out other causes of delayed ovulation or underlying conditions such as PCOS or thyroid dysfunction.
Lifestyle Matters: Supporting Fertility Naturally
Weight and nutrition
Aim for a BMI between 20–25, or the healthiest weight sustainable for you. Both under- and over-weight can disrupt ovulation and reduce sperm quality.A Mediterranean-style diet colourful plants, whole grains, legumes, nuts, olive oil, fish, minimal processed foods is associated with higher fertility and better pregnancy outcomes. And the principles of this can be adapted depending on your culture and food preferences.
Exercise
Moderate, consistent movement improves insulin sensitivity and supports healthy reproductive and metabolic function. Extreme endurance exercise or severe calorie restriction, however, can suppress ovulation and may be indicated by a change in your menstrual cycle or in extreme cases, your cycle stopping altogether. It is also very important to remain active to reduce pregnancy complications when you do conceive and guidelines suggest pregnant women get no less tha 150 minutes of moderate activity per week.
Smoking, alcohol and caffeine
Smoking shortens the reproductive lifespan and increases miscarriage and ectopic-pregnancy risk. Quitting before conception benefits both partners.
Limit alcohol to minimal intake while trying to conceive and stop once pregnant.Caffeine in moderation (≤ 200 mg per day about two cups of coffee) is safe.
Sleep, stress and mental wellbeing
Stress doesn’t directly “switch off” fertility, but chronic stress can disturb sleep, appetite, libido and hormone rhythms. Try to protect restorative sleep, build in relaxation and social connection, and seek help early if anxiety, depression, or relationship stress are affecting you. Good mental health is foundational to good reproductive health.
When to Seek Help
Most couples (around 80–85%) conceive within a year of regular, unprotected sex. If you’re:
Under 35: see your doctor after 12 months of regular, unprotected sex.
35–39: seek advice after 6 months.
40 or older: consider assessment before trying, or after 3 months if not pregnant.
Any age: seek help sooner if you have irregular or absent periods, severe pain, known endometriosis, prior pelvic infection or surgery, or if your partner has known sperm or testicular issues.
Early assessment identifies correctable problems; from ovulation disorders to sperm quality and ensures timely access to fertility treatments when needed.
The Bottom Line
Fertility is not something to fear, but something to understand. Start with knowledge, optimise your health, and remember that conception is a process, not a performance. Regular intimacy, good nutrition, adequate rest and early medical input where needed give most couples the best chance of success and a healthier pregnancy when it happens.
Further resources:
References
Tehrani FR et al. Hum Reprod 2013; 28(3): 708–714.
Karayiannis D et al. Hum Reprod 2018; 33(3): 494–502.
NICE CG156: Fertility Problems – Assessment and Treatment (2024 update).
World Health Organization. Recommendations on Pre-conception Care (2021).
ESHRE Guidelines on Pre-pregnancy Counselling and Lifestyle (2023).
Glazer CH et al. BMJ 2017; 357:j1025.
