Researchers say elevated insulin levels can be toxic to the placenta, but there are things you can do to reduce the risks.

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Researchers say they hope their findings will result in fewer miscarriages. Getty Images

If you’ve experienced pregnancy loss, you’re not alone. Miscarriage is the single most common pregnancy complication, ending roughly one in four pregnancies.

While pregnancy loss can occur for many reasons, most often the exact cause cannot be identified.

But a new study published today in the medical journal Fertility and Sterility may provide an explanation and help prevent future losses from happening in the future.

Researchers say they have found that insulin is toxic to early placenta cells and can result in miscarriage.

In addition, metformin, a common medication used for the treatment of type 2 diabetes, as well as a reduced-carbohydrate, low-sugar diet can provide a low-cost, safe solution for women with insulin resistance to carry a pregnancy to full term.

“The reason that’s important is that we really struggle with unexplained miscarriages,” Dr. Zev Williams, director of the Columbia University Fertility Center and a study co-author, told Healthline.

“Pregnancy loss is so difficult for a woman and couple on many levels and being told ‘it just happens’ or ‘just don’t stress about it’ or ‘you need to relax,’ all those things have such a negative connotation for a woman who is going through these losses,” said Williams.

Williams explains that the driving goal of their research is to do everything possible to prevent pregnancy loss.

And while the link between insulin resistance and pregnancy loss is nothing new, the culprit before this study was thought to be glucose sugar.

“Our data suggests that it might actually be insulin that’s causing the damage and that would change how we screen and treat women with recurrent pregnancy loss,” Williams said.

Insulin resistance occurs when cells in your muscles, fat, and liver don’t react properly to insulin.

Such cells are negatively impacted and can’t easily retrieve glucose from your blood.

For some women, this isn’t a critical issue. According to the National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK), “as long as your pancreas can make enough insulin to overcome your cells’ weak response to insulin, your blood glucose levels will stay in the healthy range.”

But Williams explains that the same process that keeps them in the healthy range can harm a developing placenta.

“When pregnant, this higher insulin level that they’re making may damage the placenta,” he said.

It’s Williams’ hope that insulin resistance can be detected at an early stage to prevent pregnancy loss.

“First, it was initially like, ‘Oh the sugar levels are really high, now we have to start to treat.’ Here the data is suggesting that it might even be before the sugar levels start to get high that the insulin levels are high and treatment is necessary,” Williams said.

While pre-screening is always a good idea, women in certain demographics have a higher risk of insulin resistance, according to the NIDDK.

Women with these risk factors should make insulin screening a priority prior to or in the early stages of their pregnancy:

  • overweight or obese
  • over 45
  • a family history of diabetes, heart disease, or stroke
  • sedentary
  • sleep issues
  • polycystic ovarian syndrome
  • health conditions such as hormonal imbalances, high blood pressure, and abnormal cholesterol levels
  • African American, Alaska Native, American Indian, Asian American, Hispanic/Latino, Native Hawaiian, or Pacific Islander American ethnicity

Similarly, women who are experiencing the following symptoms should make screening a priority as these can be signs of insulin resistance, according to Williams.

  • hair on the face or body
  • issues with high levels of acne
  • sometimes irregular periods

Metformin was found in the study to prevent the negative effects of elevated insulin levels on early placenta cells, but is it safe for pregnant women?

“In studies looking at pregnancies, there has been no association between use of metformin and fetal malformations or poor outcome,” Williams said.

What’s more, “metformin happens to be an incredibly well-studied, widely used, and low-cost medication that’s been used for decades for treatment of insulin resistance and diabetes,” he said.

However, Williams cautions, “like with everything, if you don’t need it, it’s not good to take.”

For Williams, when comparing the safety data of metformin to the risks of toxicity to pregnancy, there’s a clear potential benefit.

“This is one especially exciting area because the intervention is so low cost and so safe and could have potentially a very big impact in terms of reducing miscarriages,” said Williams. “The challenge is that the types of rigorous clinical trials that need to be done to show this definitively are expensive, and so we are working to get funding to conduct the proper clinical trials.”

Insulin is directly toxic to early placenta and elevated levels can lead to pregnancy loss, according to new research.

Metformin, a low-cost medication for diabetes management, as well as diet modifications in the form of reduced carbohydrates and sugar have shown promise in potentially preventing miscarriage.

Larger clinical in vitro studies are needed to confirm these findings.