Folic acid: the one supplement everyone is advised to take
UK health services advise anyone who could become pregnant and is trying to conceive to take a daily 400 microgram (400 mcg) folic acid supplement, from before conception until the 12th week of pregnancy. Folic acid reduces the risk of neural tube defects, such as spina bifida, which develop very early in pregnancy, often before a person knows they are pregnant. If folic acid was not taken before conception, the advice is to start as soon as pregnancy is known (Cambridge University Hospitals NHS Foundation Trust).
When a higher dose is recommended
Some people are advised to take a higher dose, 5 milligrams a day, which is available on prescription. NHS sources list situations such as:
- a personal or family history of neural tube defects, or a previous pregnancy affected by one;
- diabetes;
- taking anti-epilepsy medicine;
- taking antiretroviral medicine for HIV.
Some NHS sources add sickle cell disease, thalassaemia, certain bowel medicines, or a BMI of 30 or more (Public Health Agency Northern Ireland, folic acid leaflet). Because the list varies slightly between sources, a GP or pharmacist should confirm whether the higher dose applies.
Risk factors that can be changed
The NHS lists factors that can affect fertility in both partners (NHS, Infertility):
- weight: a BMI of 30 or more, or being severely underweight;
- smoking, including passive smoking;
- alcohol;
- sexually transmitted infections, chlamydia in particular, which can damage the fallopian tubes;
- exposure to some pesticides, solvents and metals;
- stress.
The WHO adds that many causes of infertility are preventable, which is why prevention, including the testing and treatment of sexually transmitted infections, is part of reproductive health care (see how common is infertility?).
Medicines and long-term conditions
People with a long-term condition, or who take regular medicines, are usually advised to talk to their doctor before trying to conceive. Some medicines need adjusting before pregnancy; conditions such as diabetes are best brought under good control first. The higher folic acid dose for certain medicines is one example of why this conversation matters.
Timing and patience
The NHS says that more than 8 out of 10 couples in which the woman is under 40 will conceive within a year of regular unprotected sex. Regular intercourse, every two to three days, avoids the need to time ovulation precisely. The advice is to see a GP after a year of trying, or sooner for women aged 36 and over or if a fertility problem is already suspected.
What is not in the official guidance
Many products marketed for conception, from "fertility teas" to multi-ingredient supplements, are not part of the official recommendations. Some contain folic acid, which is useful, alongside ingredients with little evidence. Others can be harmful in pregnancy: NHS guidance warns, for example, against supplements containing vitamin A in the retinol form during pregnancy. When in doubt, a pharmacist can check a product's ingredients.
For partners
Most of the changeable risk factors apply to men as well as women. Smoking, alcohol, weight and some exposures can affect sperm. For what a semen analysis measures and how to read it, see are sperm counts really falling?
This article summarises official UK guidance and is not personal medical advice. A GP, midwife or pharmacist can advise on your own situation, including the right folic acid dose.
Vitamin D
NHS guidance advises everyone to consider a daily vitamin D supplement of 10 micrograms during autumn and winter, and this advice also covers pregnancy and breastfeeding. Some people, including those with darker skin or who are rarely outdoors, are advised to take it all year round. Pregnancy multivitamins usually contain folic acid and vitamin D at the recommended doses.
Alcohol
The UK Chief Medical Officers advise that if you are pregnant or think you could become pregnant, the safest approach is not to drink alcohol at all, to keep risks to the baby to a minimum. Alcohol can also affect the quality of sperm, which is a reason for both partners to cut down.
Infections and vaccinations
Some infections can harm a pregnancy. Before trying to conceive, it is worth checking that vaccinations are up to date, in particular against measles, mumps and rubella; a GP can check vaccination records. Testing for sexually transmitted infections is also sensible for anyone who may have been exposed, since untreated chlamydia can damage the fallopian tubes.
Specific conditions
People with conditions that affect fertility, such as polycystic ovary syndrome or endometriosis, may need tailored advice, including on folic acid dose or on changing medicines before trying to conceive.
Caffeine and weight
NHS guidance advises limiting caffeine in pregnancy to 200 milligrams a day, roughly two mugs of instant coffee, because high intake is linked to a higher risk of low birth weight and miscarriage. Caffeine is also found in tea, cola, energy drinks and chocolate. On weight, the NHS lists a BMI of 30 or more, and being severely underweight, among the factors that can affect fertility; gradual changes towards a healthy weight can help, and a GP can offer support.
None of these steps guarantees a pregnancy, and most people who do not follow every recommendation still conceive. They are worth taking because each one reduces a known risk, for the pregnancy or for fertility, at little or no cost.