Can Agnus Castus Improve Pregnancy Chances?

Agnus castus has long been promoted as a herbal remedy for women experiencing menstrual problems, premenstrual syndrome (PMS) and difficulties conceiving. You may also see it described as Vitex, chasteberry or by its botanical name, Vitex agnus-castus.

But can Agnus castus actually improve your chances of becoming pregnant? At present, there is not enough reliable evidence to show that it improves fertility or increases pregnancy rates.

Although Agnus castus may affect some of the hormonal pathways involved in the menstrual cycle, this does not mean that taking it will make conception more likely. Anyone who is trying for a baby should also be cautious about using herbal medicines without first discussing them with a healthcare professional.

Agnus Castus (Vitex Agnus-Castus)

Agnus castus is the fruit of the chaste tree, a plant native to Mediterranean and Central Asian regions. Extracts of the fruit have been used in traditional medicine for centuries and are now widely sold as herbal supplements.

One of the better-established uses of Agnus castus is for symptoms associated with PMS. Research has suggested that some preparations may help symptoms such as breast tenderness, although the quality of the available studies varies and stronger evidence is still needed.

The evidence for fertility is considerably less convincing.

Does Agnus Castus Improve Fertility?

Despite its reputation as a fertility supplement, there is currently insufficient reliable evidence to show that Agnus castus helps women become pregnant.

The US National Center for Complementary and Integrative Health (NCCIH) states that there is not enough reliable evidence to know whether chasteberry can help with infertility.

Read the NCCIH guidance on chasteberry.

Some earlier studies have explored Agnus castus in women with menstrual cycle abnormalities or hormone-related conditions. These studies have sometimes been used to support claims that the herb can improve fertility.

However, regulating part of the menstrual cycle is not the same as demonstrating an increased chance of pregnancy. Studies specifically designed to establish whether Agnus castus improves conception or live birth rates are lacking.

The European Medicines Agency (EMA) also states that no fertility data are available for Agnus castus.

Read the European Medicines Agency information on Agnus castus.

How Might Agnus Castus Affect Hormones?

Agnus castus appears to have effects on some of the signalling systems involved in hormone regulation. In particular, researchers have investigated its possible dopaminergic effects and its relationship with prolactin.

This is one reason why the herb has been studied in women experiencing menstrual symptoms and certain cycle disturbances.

However, the hormonal system involved in ovulation and fertility is complex. It would be misleading to suggest that taking Agnus castus simply “balances hormones” or automatically improves ovulation.

If irregular periods, absent periods or another hormonal problem is making conception difficult, it is important to investigate the underlying cause rather than relying on a herbal supplement.

What Is Agnus Castus Used For?

Agnus castus is commonly promoted for a variety of women’s health concerns, including:

• premenstrual syndrome (PMS)
• breast tenderness associated with the menstrual cycle
• irregular menstrual cycles
• menopausal symptoms
• fertility problems

Of these uses, PMS has received substantially more research attention than infertility.

Even for PMS, evidence is not conclusive. NCCIH reports that some research suggests chasteberry may reduce symptoms such as breast pain or tenderness, but says higher-quality evidence is needed before firm conclusions can be drawn.

Is Agnus Castus Safe When Trying to Conceive?

This is particularly important for anyone considering Agnus castus as a fertility supplement.

The NHS advises people who are trying to become pregnant to speak to their GP if they or their partner take herbal remedies. NHS guidance on medicines in pregnancy also advises against taking herbal remedies while trying to get pregnant.

Read NHS advice on trying to get pregnant.

The EMA does not recommend Agnus castus during pregnancy. It also advises against its use while breastfeeding because there is insufficient information about its safety and it may affect lactation.

Agnus castus may also interact with some medicines. Because of its possible dopaminergic and oestrogenic effects, the EMA states that interactions with dopamine agonists, dopamine antagonists, oestrogens and antioestrogens cannot be excluded.

You should therefore speak to a doctor, pharmacist or other suitably qualified healthcare professional before taking Agnus castus, particularly if you:

• are actively trying to become pregnant
• think you may already be pregnant
• are breastfeeding
• take prescription medicines
• take hormonal medicines
• have a hormone-sensitive medical condition
• are undergoing fertility investigations or treatment

What If You Are Having Difficulty Conceiving?

If you have irregular periods or are finding it difficult to become pregnant, establishing the underlying cause is more useful than assuming that a hormonal imbalance can be corrected with a supplement.

Fertility can be affected by many factors, including age, ovulation problems, conditions such as endometriosis, sperm quality and general health.

The NHS recommends speaking to a GP if you have been trying to get pregnant for a year or more, or sooner if you already know that you or your partner may have a fertility issue.

Depending on your circumstances, fertility investigations can include checking whether ovulation is occurring, hormone testing and semen analysis.

The Bottom Line

Agnus castus is an established herbal remedy with a long history of traditional use, and there is some evidence that it may help certain PMS symptoms.

However, there is currently not enough reliable evidence to conclude that Agnus castus improves fertility or increases your chances of becoming pregnant.

Claims that it can simply correct hormonal imbalances, restore ovulation or increase pregnancy rates go beyond what current research can support.

If you are trying to conceive, particularly if you have irregular cycles or have been trying for some time, speak to your GP or another appropriate healthcare professional before using Agnus castus or another herbal fertility supplement.

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