USC Researchers Identify a Major Cause of Morning Sickness. Here’s What Pregnant Women Can Do About It

Top Findings

• Morning sickness affects about 80% of pregnancies.

• New USC research points to the placenta hormone GDF-15 as a major cause.

• Symptoms are biological, not simply emotional or psychological.

• Small meals, hydration, ginger, and avoiding triggers may help.

• Severe symptoms should be evaluated by a healthcare professional.

For generations, pregnant women have been told that morning sickness is simply a normal part of pregnancy. But new research is helping explain why it happens and could eventually lead to better treatments.

Researchers at the University of Southern California’s Keck School of Medicine found that a hormone produced by the placenta, known as GDF-15, appears to play a major role in pregnancy-related nausea and vomiting. The findings help explain why some women experience mild symptoms while others struggle with severe sickness that can interfere with daily life.

The research is especially relevant in California, where hundreds of thousands of babies are born each year and where Latino families make up a significant share of the state’s young and growing population. For many expectant mothers, understanding why symptoms occur can help reduce anxiety and improve conversations with healthcare providers.

Morning Sickness Is Extremely Common

Morning sickness affects about 80% of pregnant women.

Despite its name, it can happen at any time of day or night. Symptoms typically begin during the first trimester and often peak during the early months of pregnancy.

For many women, nausea is manageable. For others, symptoms become severe enough to affect work, family responsibilities, sleep, hydration, and nutrition.

Researchers now believe the placenta hormone GDF-15 triggers protective responses in the body that contribute to nausea, vomiting, and food aversions.

According to the USC study, the body’s immune and sensory systems appear to react to the hormone in ways that may help protect a developing pregnancy by increasing sensitivity to certain foods and smells.

One reason this study is generating attention is because it challenges the outdated idea that morning sickness is simply psychological or unavoidable.

The research suggests there is a measurable biological cause.

That may help reduce stigma for women who struggle with symptoms and could eventually lead to new prevention and treatment approaches.

For working mothers, especially those balancing jobs, childcare, and household responsibilities, severe nausea can create significant financial and emotional stress.

Among Latino families, where multigenerational households and caregiving responsibilities are common, persistent pregnancy sickness can affect entire family routines.

What Pregnant Women Can Do Right Now

While researchers continue studying new treatments, doctors already recommend several strategies that may help reduce symptoms.

Never Let Your Stomach Stay Empty

Many healthcare providers recommend eating small meals throughout the day rather than three large meals.

Keeping crackers or dry toast near the bed and eating a small amount before getting up may help reduce morning nausea.

Choose Bland Foods

Simple foods are often easier to tolerate.

Common recommendations include:

• Bananas

• Rice

• Applesauce

• Toast

• Tea

Many women find that bland foods are less likely to trigger nausea than greasy or spicy meals.

Avoid Personal Triggers

Strong smells, fried foods, heavily seasoned dishes, and certain beverages may worsen symptoms.

Because triggers vary from person to person, keeping track of foods that cause nausea can be helpful.

Drink Fluids Between Meals

Many women report feeling worse when drinking large amounts of liquid during meals.

Healthcare providers often suggest drinking water, electrolyte drinks, or other fluids between meals to help prevent dehydration.

Try Ginger

Research has found ginger may help reduce nausea in some pregnant women.

Options include:

• Ginger tea

• Real ginger ale

• Ginger candies

• Ginger supplements approved by a healthcare provider

Consider Acupressure Bands

Some women experience relief using acupressure wristbands commonly sold for motion sickness.

Change When You Take Prenatal Vitamins

Prenatal vitamins can sometimes worsen nausea.

Many providers recommend taking them before bed with a light snack.

When Should You Call Your Doctor?

Most morning sickness improves over time.

However, women should contact their healthcare provider if they experience:

• Inability to keep fluids down

• Signs of dehydration

• Significant weight loss

• Severe vomiting

• Dizziness or fainting

In some cases, women develop hyperemesis gravidarum, a serious pregnancy condition that requires medical attention.

Healthcare providers may recommend treatments such as Vitamin B6, doxylamine, or prescription medications when symptoms become difficult to manage.

This research offers something many pregnant women have wanted for years: a clearer explanation.

Understanding the biological causes of pregnancy nausea may eventually improve treatment options and reduce the frustration many women feel when symptoms interfere with work, family life, and daily routines.

For families preparing for a new baby, the message is reassuring.

Morning sickness is common, it has a biological basis, and effective strategies exist to help many women manage symptoms safely while researchers continue searching for better solutions.