The term pica refers to the ingestion of nonnutritive substances. It can be a feature of severe anemia and also reportedly is frequent in pregnant women. Pica is especially common in certain geographic areas such as sub-Saharan Africa and, in Western societies, it seems to be particularly prevalent in African-Americans, foreign-born women, and less privileged groups. Among the substances most commonly craved and eaten are clay, laundry starch, soap, and chalk. One meta-analysis found that 30% of 50% of pregnant women had pica (Horner RD et al. J Am Diet Assoc 1991;91:34).
The investigators prospectively determined the frequency of pica in 100,000 pregnant women registered in the Danish National Birth Cohort in the years 1996–2002, who represented approximately one-third of all pregnant women in Denmark. Food frequency questionnaires were sent during the 25th week of gestation, and 70% were returned. Participants had an average age of 29 years and were generally of high socioeconomic status. Only 14 respondents, 0.02% of the total, reported having eaten substances that were clearly not foods. Substances mentioned more than once included clay or soil, toothpaste, and chalk. Individual respondents reported eating things as diverse as coffee grounds, toilet paper, soft sponge, lavender flowers, and roses.
The authors conclude that, at least in well-nourished populations like the Danish, pica during pregnancy is more a myth than a reality.