Pica has been associated since classical times with pregnant women. Until the twentieth century, pregnancy was commonly believed to cause mental instability - manifested, for example, in unusual food cravings. More recent studies of food preferences during pregnancy, however, report that changes in these, as well as the onset of specific cravings, are not universal phenomena.
Much of the research on pica among pregnant women in the United States has focused on those living in rural areas. The prevalence of pica among women considered at risk seems to have declined by about half between 1950 and 1970, but it has remained fairly constant from 1970 to the present. Nonetheless, it was estimated that pica is practiced by about one-fifth of pregnant women in the United States who are considered at “high risk” for this behavior. “High-risk” factors include being. African-American, living in a rural area, having a family history of pica, and having practiced pica during childhood (Horner et al. 1991). Pregnant black women are over four times more likely than their white counterparts to engage in pica behavior. Additionally, pregnant women living in rural areas are more than twice as prone to pica as those living in urban areas.
Although some investigators have found no significant association between age and pica among pregnant women (Dunston 1961; Butler 1982), others have observed that pregnant women who practice pica tend to be relatively older than those who do not. It is interesting to note that women who report consuming clay tend to be older than those who report consuming starch (Vermeer and Frate 1979). One study, reanalyzing data from previous research, indicated that pregnant women who did practice pica were six times as likely to have a history of childhood pica than pregnant women who did not. Women who practice pica during pregnancy are also more likely to report pica behavior among family members, particularly their mothers and grandmothers (Lackey 1978). Little evidence of pica among white and upper-income women may reflect a lack of research among these populations (Keith, Brown, and Rosenberg 1970; Horner et al. 1991).
Among pregnant women in the United States, the three forms of pica that occur most frequently are geophagia, amylophagia, and pagophagia (Horner et al. 1991). Although, as we have noted, some researchers believe that as African-American women migrated to northern urban areas, laundry starch became a substitute for the more traditional clay eaten in the South (Keith et al. 1970), other research indicates that consumption preferences themselves might be changing, with younger women preferring starch over clay. In one study of rural women in North Carolina, participants indicated a preference for starch, even though their mothers had consumed both clay and starch (Mansfield 1977). Explanations of pica during pregnancy, like those of pica in general, range from the psychological through the cultural, to the nutritional (Horner et al. 1991; Edwards et al. 1994).
A recent study of eating habits and disorders during pregnancy mentions the case of a woman who, at 32 weeks of pregnancy, developed a craving for coal, reporting she found it “irresistibly inviting” (Fairburn, Stein, and Jones 1992: 668).Two other participants in the study developed a taste for eating vegetables while still frozen, which indicates something of the difficulty involved in determining pica incidence. The consumption of frozen vegetables, although not defined as pica by these researchers, would surely be considered a type of pagophagia by others.
In terms of medical consequences, pica has been related to anemia and toxemia among pregnant women and newborn infants (Horner et al. 1991). In some cases, pica reportedly contributed to dysfunctional labor (through impacted bowels) and maternal death (Horner et al. 1991). Pica during pregnancy has also been associated with a “poor” functional status of fetuses and infants, perinatal mortality, and low birth weight.
The authors of a report on pica in the form of baking-powder consumption that caused toxemia during pregnancy have pointed out that previous investigators discovered a significant correlation between toxemia and geophagia, but not between toxemia and amylophagia (Barton, Riely, and Sibai 1992). The case involved a 23-year-old black woman with anemia and hypokalemia who admitted to a one-and-a-half-year history of consuming up to 7 ounces of Calumet baking powder daily. The baking powder was considered a family remedy for gas discomfort. Ingestion of baking powder, comprised of 30 percent sodium bicarbonate with cornstarch, sodium aluminum sulfate, calcium acid phosphate, and calcium sulfate, is known to increase blood pressure. In this case, liver dysfunction and hypokalemia also resulted.
The psychological aspects of pica among pregnant women are similar to those of other pica practitioners. In addition to reporting a craving for the ingested substance, pregnant women exhibiting pica commonly say that they feel anxious when the substance is unavailable yet experience a sense of considerable satisfaction during and after eating the substance (Horner et al. 1991).
Pica and Iron Deficiency
Although no definitive connection has been established between pica and nutritional deficiencies, many have consistently linked pica with iron deficiency and its consequent anemia. Indeed, some have estimated that upward of 50 percent of patients with iron-deficiency anemia practice pica (Coltman 1969; Crosby 1976). It is interesting to note that the correlation of pica with anemia dates back to medieval times, and that iron therapy was prescribed as a cure even then (Keith et al. 1970).
As pointed out previously, pica behavior during pregnancy has also been strongly associated with iron-deficiency and iron deficient anemia. What remains unresolved is a problem of cause and effect. As Dennis F Moore and David A. Sears wrote: “Some authors have suggested that the habit may induce iron deficiency by replacing dietary iron sources or inhibiting the absorption of iron. However, considerable evidence suggests that iron deficiency is usually the primary event and pica a consequence” (1994: 390). Although some insist that ingested starch inhibits iron absorption, Kenneth Talkington and colleagues (1970) have reported that this is not the case. These authors concluded that iron deficiency and anemia result from amylophagia only when laundry starch replaces nutritional substances in the diet.
Turning to clay ingestion, studies have found that its effect on iron absorption varies and depends upon the type of clay ingested. Some clays impair iron absorption, whereas others contain large amounts of iron. However, as already mentioned, there is no consistent agreement that iron from clay is useful in correcting anemia (Coltman 1969; Keith et al. 1970; Crosby 1976).
Coltman (1969), who first used the term pagopha-gia, was also one of the first to link the practice with iron deficiency. Indeed, he reported that the compulsive consumption of ice could be stopped within one or two weeks with iron treatment, even in instances where iron supplementation was not sufficient to correct iron-deficiency anemia. This dovetails with the work of William H. Crosby (1976), who has noted that although ice neither displaces other dietary calories nor impairs iron absorption, it is still the case that pagophagia is diminished when treated with iron supplements. Moreover, other cases of pica involving unusual ingested substances (e. g., toothpicks, dust from venetian blinds, and cigarette ashes) also respond positively to iron supplements (Moore and Sears 1994).
Perhaps even more powerful support for iron deficiency as a cause of pica comes from findings that intramuscular injections of iron diminish the habit of pica in children. But there is also evidence that intramuscular injections of a saline solution have the same effect, suggesting that the additional attention paid to children with pica behavior may help to reverse the condition (Keith et al. 1970).
Countering this theory, however, are two cases of childhood pica in which parental attention was apparently not a factor. One involved a 6-year-old boy with a 2-year history of ingesting large amounts of foam rubber, whereas the second case was that of a 2-year-old boy with a 6-month history of eating plastic and rubber items. Both of these cases of pica behavior were resolved through the administration of iron supplements, even though there was no increase in parental attentiveness (Arbiter and Black 1991).
In 1970, Louis Keith, E. R. Brown, and L. Rosenberg summarized the medical questions surrounding pica that required further investigation and clarification. These were:
1. Is iron-deficiency anemia a direct adverse consequence of pica?
2. Is iron-deficiency anemia an indirect result of nutritional replacement by unnatural substances, allaying the appetite for nutritional foods by filling?
3. Are so-called cures of the habit of pica among children the result of increased attention or of injections of iron or saline solution?
4. If those “cures” among children are the result of therapy, should the therapy consist of iron injections, saline injections, or an adequate diet high in iron content?
5. Is the mechanism of pica among children different from that among adults, especially pregnant women? Would injections of iron reverse the habit in pregnant women?
6. Does the coexistence of amylophagia and anemia adversely affect the pregnant woman, or are these two separate and distinct unrelated concomitant adverse conditions? (1970:630)
As we have seen, although almost three decades have elapsed, there is still no consensus within the medical community regarding the answers to these questions. Instead, they are still being asked.
The physiological mechanism linking iron deficiency and pica behavior is not known. As Crosby noted, “Somewhere in our emotional circuits iron deficiency can sometimes cross the wires” (1976: 342). Somewhat more scientifically, it has been suggested that pica cravings are generated by a functional disorder of the hypothalamus, which is sensitive to changes in iron levels (Castiglia 1993).
As for pagophagia, Mary Elks (1994) has made two observations. She noted that even in industrialized nations, both geography and culture play a role in determining how pagophagia is viewed. For example, in England and other European countries compulsive ice eating is considered pathological behavior, perhaps indicative of disease. However, in the warmer climate of the southern United States, ice eating may be regarded as normal. In addition, she reported a case involving an entire family practicing pagophagia, including a 14-month-old girl for whom, Elks believed, ice consumption should not be assumed to be a learned behavior. She suggested that in some cases, familial or heritable factors cause pagophagia that is independent of other types of pica and probably not correlated with iron deficiency.
World History
