Can Evening Primrose Oil Increase Your Fertility?

Evening primrose oil (EPO) is a plant-based supplement containing gamma-linolenic acid (GLA), an omega-6 fatty acid. It has long been promoted for a range of health uses, including fertility, but evidence that taking evening primrose oil improves fertility or increases the chance of conception is currently limited.

If you are trying for a baby, it is therefore important to distinguish between commonly repeated claims about evening primrose oil and benefits that have been demonstrated in good-quality clinical research.

Contents

• What is Evening Primrose Oil?
• Can Evening Primrose Oil Improve Fertility?
• Evening Primrose Oil and Cervical Mucus
• Should You Take Evening Primrose Oil When Trying to Conceive?
• Evening Primrose Oil and Pregnancy
• Side Effects and Interactions
• The Bottom Line

What is Evening Primrose Oil?

Evening primrose oil is extracted from the seeds of the evening primrose plant, Oenothera biennis. The oil contains linoleic acid and gamma-linolenic acid (GLA), both omega-6 fatty acids.

GLA is converted by the body into substances involved in a number of normal biological processes. Evening primrose oil supplements have therefore been promoted for conditions including premenstrual symptoms, breast discomfort and some inflammatory or skin conditions, although the strength of evidence varies considerably depending on the condition.

Supplements are usually sold as softgel capsules containing a measured quantity of evening primrose oil and GLA.

Can Evening Primrose Oil Improve Fertility?

Evening primrose oil is sometimes promoted as a fertility supplement, particularly because it contains GLA. However, there is currently limited good-quality clinical evidence showing that taking evening primrose oil improves female fertility, regulates ovulation, balances reproductive hormones or increases pregnancy rates.

This is important because many of the fertility claims surrounding EPO have become widely repeated online without being supported by strong clinical studies.

Having regular ovulation, healthy sperm, appropriately timed intercourse and a reproductive system capable of supporting fertilisation and implantation are all important parts of conception. There is not currently enough evidence to show that evening primrose oil has a significant beneficial effect on these processes.

Evening Primrose Oil and Cervical Mucus

One of the most common fertility claims made about evening primrose oil is that it can increase or improve cervical mucus.

Cervical mucus does play an important role in conception. Around ovulation, rising oestrogen levels normally cause cervical mucus to become wetter, clearer and more slippery. This fertile mucus can help sperm move through the cervix towards the uterus and fallopian tubes.

However, while evening primrose oil is often recommended online as a way of improving fertile cervical mucus, there is not enough reliable clinical evidence to show that taking EPO improves cervical mucus or increases the chance of pregnancy.

Should You Take Evening Primrose Oil When Trying to Conceive?

Because evidence for a fertility benefit is limited, evening primrose oil should not be viewed as a proven treatment for infertility or as a substitute for medical fertility advice.

There is also uncertainty about its use around conception and pregnancy. Cambridge University Hospitals advises that evening primrose oil should not be taken during pregnancy or while trying to conceive.

If you are considering taking evening primrose oil while trying for a baby, speak to your GP, pharmacist or fertility professional first, particularly if you take regular medication or have an existing medical condition.

Evening Primrose Oil and Pregnancy

The evidence surrounding the safety of evening primrose oil during pregnancy is inconclusive. This means it would be inappropriate to state that EPO has been proven either safe or harmful during pregnancy.

Current UK hospital guidance advises avoiding evening primrose oil during pregnancy and when trying to conceive. If you discover that you are pregnant while taking EPO, speak to your pharmacist, midwife or GP for individual advice rather than relying on information from supplement websites or online forums.

Claims that evening primrose oil has been proven to cause miscarriage are not supported by good-quality evidence and should not be treated as established fact.

Side Effects and Interactions

Evening primrose oil is generally well tolerated by many adults, but supplements can still cause side effects or interact with medicines.

Possible side effects may include:

• Stomach discomfort
• Nausea
• Diarrhoea
• Headache

Extra caution may be needed if you take anticoagulant or antiplatelet medicines, have epilepsy or take medicines that could affect seizure risk. If you take prescription medicines, it is sensible to ask a pharmacist or doctor before starting evening primrose oil.

The Bottom Line

Evening primrose oil is a popular supplement and is frequently promoted to women who are trying to conceive. In particular, you may encounter claims that it balances hormones or improves fertile cervical mucus.

At present, however, there is not enough good-quality evidence to conclude that evening primrose oil improves fertility or increases the chance of pregnancy. UK hospital guidance also advises avoiding EPO while trying to conceive and during pregnancy.

If you have been trying to conceive without success, particularly for a prolonged period, speak to your GP rather than relying on supplements alone. They can advise whether fertility investigations or specialist support may be appropriate.

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