Can Soy Isoflavones Help In Getting Pregnant?

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According to the Center for Disease Control and Prevention (CDC), about ten in one hundred women in the US have difficulty becoming pregnant (1). The reasons may vary, but in most cases, it could be the individual’s lifestyle and environment.

Women have been using supplements derived from natural sources to get pregnant. Among them are soy isoflavones, which are plant-based compounds. But how safe are soy isoflavones, and can they really help you get pregnant?

In this post, MomJunction tells you whether soy isoflavones are indeed helpful for women who want to conceive. We also answer some frequently asked questions about soy isoflavones and pregnancy.

What Are Soy Isoflavones?

Soy isoflavones are dietary supplements derived from soybeans containing phytoestrogen isoflavones. They help in regulating hormonal imbalance, reduce the risk of breast cancer, heart disease, and osteoporosis (2).

Can Soy Isoflavones Help In Getting Pregnant?

There are limited studies to prove if soy isoflavones could help you get pregnant. Two previous clinical studies found out that women who were undergoing infertility treatment had higher pregnancy and live birth rates after the intake of soy isoflavones. The third study, which looked at 315 women who underwent 520 artificial reproductive treatments, found that dietary intake of soy was positively related to the probability of having a live birth (3).

However, the strength of isoflavones used in the study was 100 times higher than the regular intake of women in the west and ten times higher than Asian women (3). This study also states that additional research is needed for a better understanding of the association between soy isoflavones and improved chances of pregnancy, considering the limitations to their study.

Although studies indicate that the intake of soy isoflavones could increase your chances of conception in some cases, there is no definite study to prove that soy isoflavones alone can improve fertility in women.

Who Can and Cannot Take Soy Isoflavones?

Talk to your doctor before you take soy isoflavones, as there is no definitive research to back their effectiveness.

  • Soy isoflavones are known to mimic the actions of estrogen (a hormone that triggers the cyclic reaction of ovulation). So, if you are diagnosed with infertility because of low estrogen, then soy isoflavones could begin the ovulation process. However, there is no scientific study to prove this.

If your menstrual cycles are regular and you are not experiencing any infertility problems, then it is best to stay away from these supplements as high doses of soy isoflavones could cause hormonal imbalance and infertility issues (4).

Also, soy isoflavones did not seem to have a therapeutic effect in the case of polycystic ovarian syndrome (PCOS) (5). So, you may restrict the use of these supplements if you are diagnosed with PCOS, or check with your doctor before trying them.

What Is The Ideal Dosage Of Soy Isoflavones For Fertility?

Further research is needed to determine the ideal dosage of soy isoflavones to improve fertility. The dosage could vary from person to person, their ability to digest the hormone, and also their dietary preferences (for example, Asians have a higher tolerance to soy than Western population) (4).

The intake of natural soy as part of the diet has been followed for many years in countries like Japan. However, the safety of supplements is still under question.

How To Use Soy Isoflavones?

Follow the instructions of your doctor and take the supplements accordingly. Also, refrain from taking multiple doses and more than the prescribed dosage, as high doses of soy isoflavones can cause certain side effects.

What Are The Side-Effects Of Soy Isoflavones?

In animals, intake of phytoestrogens had an impact on the fertility and morphogenesis of the ovaries and was also associated with disorders of sexual development in male rats (6).

Data from a study suggests that consuming excess soy isoflavones (>100mg/ day) can lead to reduced ovarian function in premenopausal women (7). Also, specific tissues such as the breast, uterus, and ovaries are sensitive to estrogen, and large doses of soy isoflavones can cause cancerous cells in them. Additionally, you may also experience short-term side effects such as headache, fatigue, breast tenderness, and indigestion.

Are Soy Isoflavone Supplements Safe?

Soy isoflavones are sold as dietary supplements, so, the US Food and Drug Administration does not approve of them. They are also not subjected to rigorous testing for their safety or suitability. While the dietary intake of soy (in limited quantity) may not cause any adverse effects, there are no well-controlled studies to say the same in the case of supplements.

If you are not allergic to soy and are not comfortable with other methods to combat infertility, you may talk to your doctor before trying these supplements.

Did you take soy isoflavones to get pregnant? Share your experiences with us by commenting in the section below.

This post is for informational purposes only and is not a replacement for a doctor’s consultation. Do not use any medication without talking to your doctor.


MomJunction's health articles are written after analyzing various scientific reports and assertions from expert authors and institutions. Our references (citations) consist of resources established by authorities in their respective fields. You can learn more about the authenticity of the information we present in our editorial policy.
1.Female Infertility; U.S Department of Health & Human Services
2.Soy isoflavones; NCI Drug Dictionary; National Cancer Institute
3.Jose C. Vanegas et al.; Soy food intake and treatment outcomes of women undergoing assisted reproductive technology; NCBI (2015)
4.Bjarne K Jacobsen et al.; Soy isoflavone intake and the likelihood of ever becoming a mother: the Adventist Health Study-2; NCBI (2014)
5.Daniela Romualdi et al.; ; Is there a role for soy isoflavones in the therapeutic approach to polycystic ovary syndrome? Results from a pilot study; American Society for Reproductive Medicine
6.Sergei V. Jargin; Soy and Phytoestrogens; Possible side effects; NCBI (2014)
7.Wendy N Jefferson; Adult Ovarian Function Can Be Affected by High Levels of Soy; NCBI (2010)

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