Pregnant women eat clay, ice, and soil - and most doctors never find out

In a North Carolina study, 38% of rural pregnant women were eating non-food substances - clay, soil, ice, baking powder, cornstarch. Yet 75% of them had no mention of the behavior anywhere in their medical records. Their doctors simply did not know.

This condition is called pica: the craving and consumption of items with no nutritional value. It is common during pregnancy worldwide, particularly in African American, Hispanic, and rural populations. In a California study, 51% of Hispanic women reported it. Complications include anemia, abnormal gestational weight gain, high blood pressure, and adverse birth outcomes - plus the direct risks of ingesting heavy metals, parasites, and toxins that contaminate some of these substances.

Despite those stakes, only two studies have examined pica in U.S. populations in the last 25 years. A new pilot study at the University of South Carolina, funded by the USC Collaborative for Health Equity Research (CHEER), aims to change that.

Biology, culture, and stigma

Leila Larson, an assistant professor of health promotion, education, and behavior at USC's Arnold School of Public Health, has studied pica across multiple countries, including research in Malawi that showed a reduction in earth consumption when iron supplements were provided. That finding points to one of the suspected causes: micronutrient deficiency, particularly iron. The body may drive cravings for non-food items as a misguided response to nutritional gaps.

But the picture is more complicated than simple deficiency. Pica is simultaneously a biological response to nutritional stress, a cultural practice with deep roots in many communities, and a behavior surrounded by shame in clinical settings. In some parts of the world, consuming certain types of earth during pregnancy is normal and expected. In American healthcare, women often fear reporting it.

"Pica is viewed as a cultural practice, as well as a biological response to nutritional deficiencies, infection or stress," Larson said. "But with so little research on the topic, we just don't know enough about its prevalence, causes or impacts on pregnant women and their babies."

The South Carolina focus

The Southern United States has particularly high rates of prenatal anemia, making it a region where pica is likely common but largely invisible to the healthcare system. Larson's study will investigate which South Carolina populations are most affected, what drives the behavior in these communities, and how pregnant women experience pica in their daily lives.

The research team includes clinical, community, and research experts, and the study includes a Community Advisory Board to ensure the research approaches and materials are culturally appropriate. That engagement is critical: any screening or treatment protocol that emerges from this work will need to account for the cultural dimensions of pica rather than treating it purely as a medical problem to be eliminated.

From pilot to protocol

The long-term goal is to develop culturally relevant screening and treatment protocols that healthcare providers can use. Currently, most prenatal care does not include systematic pica screening, and when the topic does come up, it is often handled with insufficient understanding of the cultural context.

The study's ironical challenge is embedded in the condition itself: the non-food items women with pica consume often worsen the very deficiencies that may be driving the cravings. Clay and soil can reduce iron absorption while introducing contaminants. The cycle reinforces itself unless interrupted by both nutritional intervention and culturally sensitive clinical support.

This is a pilot study - a first step toward understanding a condition that has been largely ignored by the U.S. research community despite affecting, by the limited data available, somewhere between a third and a half of pregnant women in affected populations. Whether it leads to scalable screening tools and effective interventions will depend on what the researchers find and whether the healthcare system is willing to ask questions it has largely avoided.