How to Increase Your Chances of Getting Pregnant: 7 Evidence-Based Steps

Trying for a baby can feel like it's out of your hands. Some of the biggest factors, like age and genetics, are. But plenty is within your control, and it applies to both partners. As a dietitian, these are the changes I see the strongest evidence for.

1. Does weight affect your chances of getting pregnant?

Yes. Being well under or over a healthy weight can make periods irregular or stop ovulation altogether. Very low energy intake, a very low body weight or heavy training can switch off the hormone signals from the brain that trigger ovulation.⁶ Carrying excess weight also raises the risk of pregnancy complications, including gestational diabetes, pre-eclampsia, birth defects and needing a caesarean.

For women with obesity who aren't ovulating regularly, losing even 5–10% of body weight can improve the chance of conceiving. For people who are underweight, regaining weight can help periods return.⁶ In trials, structured eating and activity programs increased pregnancy and live birth rates compared with no support.¹

How an Accredited Practising Dietitian can help

An APD can help you reach a healthy weight without under-eating or over-restricting. They make sure you're getting enough of the nutrients that matter before pregnancy, build a plan around your routine, and look at your recent blood tests with you. Often a modest, steady change is all that's needed.

2. How to improve sperm quality: it takes two

Fertility isn't only a women's health issue. A male factor plays a part in around 40–50% of infertility cases, either on its own or alongside a female factor.² A semen analysis checks sperm count, how well sperm move (motility), their shape (morphology) and how many are alive (vitality), using World Health Organization standards.

Men who eat a Mediterranean-style diet rich in fish, vegetables, fruit, nuts and wholegrains, and who limit processed meat, alcohol and sugary drinks, tend to have better sperm quality. Antioxidant supplements are widely marketed for male fertility, but the best evidence is low certainty.² Talk to your practitioner before spending money on them.

3. Quit smoking, both of you

People who smoke take longer to get pregnant and are less likely to conceive than non-smokers, and need nearly twice as many IVF attempts to conceive.³ Smoking damages the DNA in eggs and sperm, disrupts hormones, affects how a fertilised egg travels to the uterus, and changes the environment inside the uterus. In men it's linked to lower sperm count and poorer sperm movement.³

Second-hand smoke is nearly as harmful as smoking yourself,³ so the best thing you can do is both quit and keep your home smoke-free. Your practitioner, or the Quitline on 13 78 48, can help.

4. Which supplements should you take when trying to conceive?

• Folic acid: at least 400 micrograms a day, starting at least one month before you conceive and continuing through the first three months of pregnancy. It significantly lowers the risk of neural tube defects such as spina bifida.⁴
• Iodine: 150 micrograms a day when planning a pregnancy, during pregnancy and while breastfeeding, to support your baby's brain development. If you have a thyroid condition, check with your doctor first.⁷

Choose a supplement with your practitioner or pharmacist so the doses match Australian guidelines.

5. Eat for fertility: what the evidence supports

Build meals around vegetables, fruit, legumes, wholegrains, fish, nuts and olive oil. This Mediterranean-style pattern covers the nutrients that matter before pregnancy and is the same pattern linked with better sperm quality.

• Alcohol: Australian guidelines advise no alcohol when you're planning a pregnancy.⁸
• Caffeine: keep it to 200 mg a day or less, about two cups of instant coffee.⁹

6. Can stress affect getting pregnant?

Severe or prolonged stress can disrupt the brain signals that control ovulation, especially when combined with under-eating or heavy exercise. For everyday stress the picture is less clear. Studies link higher stress with taking longer to conceive,⁵ but they can't prove that stress is the cause. Trying to conceive is stressful in itself.

Looking after your mental health matters in its own right, and a psychologist or counsellor can help. Feeling stressed doesn't mean you've caused a fertility problem.

7. Should you worry about BPA?

BPA (bisphenol A) is a chemical found in some hard plastics, food-can linings and till receipts. It can mimic oestrogen in the body. Some studies link higher BPA levels with fewer eggs collected during IVF and, in men with heavy workplace exposure, lower sperm count and motility. The human evidence is still mixed, and BPA hasn't been shown to cause miscarriage.

A few low-cost steps reduce your exposure: choose fresh over canned food where you can, don't heat food in plastic, and use glass or stainless steel containers.

When should you get help?

Speak to your practitioner or a fertility specialist if you haven't conceived after 12 months of regular unprotected sex and you're under 35, or after 6 months if you're 35 or over.⁶ Go sooner if you're over 40, have irregular or absent periods, or either partner has a known condition that can affect fertility.

Frequently asked questions

Does weight affect your chances of getting pregnant?

Yes. Being well under or over a healthy weight can disrupt ovulation. For women with obesity who aren't ovulating, losing 5–10% of body weight can improve the chance of conceiving.

How long should it take to get pregnant?

Most couples conceive within a year. Seek advice after 12 months of trying if you're under 35, or after 6 months if you're 35 or over.

Can men improve their sperm quality?

Quitting smoking, eating a Mediterranean-style diet and keeping a healthy weight are linked with better semen quality. The evidence for antioxidant supplements is low certainty.

Which supplements should I take when trying to conceive?

Australian guidelines recommend folic acid (at least 400 micrograms a day, starting at least a month before conception) and iodine (150 micrograms a day).

Can stress stop you getting pregnant?

Severe stress can suppress ovulation. Everyday stress is linked with taking longer to conceive but hasn't been proven to cause infertility.

Is it OK to drink alcohol or coffee while trying to conceive?

Australian guidelines advise no alcohol when planning a pregnancy, and keeping caffeine to 200 mg a day or less.

References

Research (PubMed)

1. Hunter E, Avenell A, Maheshwari A, Stadler G, Best D. The effectiveness of weight-loss lifestyle interventions for improving fertility in women and men with overweight or obesity and infertility: a systematic review update of evidence from randomized controlled trials. Obes Rev. 2021;22(12):e13325. PubMed 34390109
2. de Ligny W, Smits RM, Mackenzie-Proctor R, et al. Antioxidants for male subfertility. Cochrane Database Syst Rev. 2022;5:CD007411. PubMed 35506389
3. Practice Committee of the American Society for Reproductive Medicine. Tobacco or marijuana use and infertility: a committee opinion. Fertil Steril. 2024;121(4):589–603. PubMed 38284953
4. De-Regil LM, Peña-Rosas JP, Fernández-Gaxiola AC, Rayco-Solon P. Effects and safety of periconceptional oral folate supplementation for preventing birth defects. Cochrane Database Syst Rev. 2015;(12):CD007950. PubMed 26662928
5. Lynch CD, Sundaram R, Maisog JM, Sweeney AM, Buck Louis GM. Preconception stress increases the risk of infertility: results from a couple-based prospective cohort study – the LIFE study. Hum Reprod. 2014;29(5):1067–1075. PubMed 24664130

Australian guidelines

6. Your Fertility (Australian Government-funded fertility education program). Weight, smoking and age. View source
7. National Health and Medical Research Council. Iodine supplementation for pregnant and breastfeeding women. 2010. View source
8. National Health and Medical Research Council. Australian guidelines to reduce health risks from drinking alcohol. 2020. View source
9. healthdirect Australia. Caffeine. View source

This article is general information and isn't a substitute for personalised advice. Speak to your practitioner about your situation.