Pica in pregnancy

INTRODUCTION — Pica is the craving and intentional consumption of substances not culturally defined as food [1]. This topic will provide an overview of pica, focusing on its diagnosis, consequences, and management in pregnant persons.

TYPES — There are three main types of pica:

●Geophagy (or sometimes geophagia) – The consumption of earth, including soil or other earth-rich items such as adobe, clay preparations, pottery, or bean stones (clumps of earth among dried beans).

●Amylophagy (or amylophagia) – The consumption of raw starches, including cornstarch, laundry starch, raw rice (ryzophagia) [2], and flour.

●Pagophagy (or pagophagia) – The consumption of large quantities of ice or freezer frost.

Earth, raw starch, and ice are the most commonly consumed pica substances. Chalk, charcoal, ash, paper, toilet paper, coffee grounds, baby powder, and paint chips are also common choices.

DIAGNOSIS — The American Psychiatric Association's Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (DSM-5-TR) diagnosis of pica requires each of the following [3]:

●Repeated eating of nonfood substances (eg, chalk, clay, cloth, coal, dirt, gum, hair, metal, paint, paper, pebbles, soap, string, or wool) that are not nutritional for at least one month.

●The eating behavior is inappropriate to the individual's developmental level and is not culturally supported or socially normal.

●If the eating behavior occurs in the context of another mental disorder (eg, autism, intellectual disability, or schizophrenia) or general medical condition (including pregnancy), the severity of the eating behavior warrants additional clinical attention.

DSM-5-TR distinguishes pica from nonsuicidal self-injurious behaviors in which individuals swallow potentially harmful objects (eg, batteries, knives, or needles) [3].

The diagnosis of pica can also be made when the individual reports craving that is provoked by taste, smell, or texture (hapticophagia) [4], but the actual consumption of these substances has not yet occurred. It can also be made in individuals with amylophagy or pagophagy, although the DSM-5-TR does not allow consumption of "food" items such as flour, raw rice, and ice to be considered pica [3].

EPIDEMIOLOGY AND COURSE IN PREGNANCY

●Prevalence – The prevalence of pica varies across countries and ethnic groups, by health status, and by diagnostic criteria [1,5]. In a meta-analysis assessing the worldwide prevalence of pica during pregnancy and the postpartum period, the mean prevalence during pregnancy was much higher in Africa (45 percent) than in either North/South America (23 percent) or Eurasia (18 percent) [6]. Prevalence is in the 30 to 40 percent range in most studies among pregnant persons in the United States [5], but prevalences as low as 8 percent and as high as 77 percent have been reported [7,8]. However, studies likely underestimate the true prevalence, given that clinicians often do not ask patients about this behavior and patients may fail to disclose pica because they feel shame or fear chastisement [5].

●Demographics – Pregnant persons are by far the most likely demographic group to engage in pica, followed by school-age children [9]. Individuals with some medical disorders, such as iron or zinc deficiency, anemia (of many etiologies), celiac disease, and end-stage kidney disease on dialysis, are also prone to developing pica [1,10,11].

Geographically, pica is most commonly reported among individuals living in or originating from warm, moist climates (ie, tropical or temperate regions) [9]. It has been described as more prevalent in Latin American [12,13] and Black populations [14-17]. Geophagy and amylophagy specifically are common during pregnancy in many regions, including sub-Saharan Africa, the Southeastern United States, and the Indian subcontinent [5,13,18].

●Course in pregnancy – The course of pica in pregnancy is variable and unpredictable; the behavior may decrease or increase [19].

POSSIBLE ETIOLOGIES — The etiology of pica is unclear [1]. Hypotheses include the following:

●It is a functional attempt to increase levels of deficient micronutrients; however, this is unlikely to explain much of pica because most substances do not have bioavailable micronutrients.

●It is a nonfunctional epiphenomenon or side effect of a micronutrient deficiency. The micronutrient deficiencies most commonly associated with pica are iron and, to a lesser extent, zinc [5]. An association with lower selenium levels, along with an elevated oxidative stress index, has also been reported [20]. Although there are many case studies in which iron supplementation preceded the disappearance of pica cravings, there is no conclusive evidence of a causal relationship between pica cravings and micronutrient deficiencies.

●It is a protective behavior that helps shield the individual from harmful pathogens or chemicals during times of increased vulnerability, such as pregnancy. While some pica substances are clearly adsorptive and/or bind with the mucin layer of the gut and thus may be protective by binding with plant toxins, harmful chemicals, or pathogens, others, such as ice, are inconsistent with this hypothesis. Some pica substances, such as ice and clay, may be palliative to gastrointestinal distress (eg, soothe nausea, reduce ptyalism and diarrhea) [1].

●Geophagy may improve a mother's immunity during pregnancy and lactation, possibly by altering the microbiome/intestinal flora, although minimal data are available [21,22].

DIFFERENTIAL DIAGNOSIS

●Associated medical disorders – Pica related to an underlying medical disorder (eg, iron or zinc deficiency, anemia, celiac disease, end-stage kidney disease on dialysis) can be confirmed or excluded by history, appropriate laboratory studies, and/or physical examination [23].

Pica involving smelling/sniffing gasoline could represent a substance use disorder rather than pica. (See "Screening for unhealthy use of alcohol and other drugs in primary care" and "Clinical assessment of substance use disorders".)

Pagophagy may be secondary to thirst and dehydration, possibly due to nausea and vomiting of pregnancy or hyperemesis gravidarum. (See "Nausea and vomiting of pregnancy: Clinical findings and evaluation".)

●Psychiatric disorders – A small fraction of pica cases in nonpregnant individuals has been associated with a psychiatric disorder, including obsessive compulsive disorder, schizophrenia, and anorexia nervosa [24]. These disorders often can be excluded by history, but if suspected, the diagnosis needs to be confirmed and treated by a mental health professional. (See "Obsessive-compulsive disorder in adults: Epidemiology, pathogenesis, clinical manifestations, course, and diagnosis" and "Schizophrenia in adults: Clinical manifestations, course, assessment, and diagnosis" and "Anorexia nervosa in adults: Clinical features, course of illness, assessment, and diagnosis".)

Pagophagy has been associated with autism spectrum disorder, dementia, and psychosis [25].

●Other – Pagophagy may be practiced as an analgesic for oral pain, including glossitis or xerostomia [25].

POSSIBLE CONSEQUENCES — The clinical findings in individuals with pica depend on the type and quantity of substances being consumed and whether toxins have contaminated these substances. Potential clinical sequelae are listed in the table (table 1) and are described below. While multiple case studies have reported serious adverse outcomes associated with pica, many individuals who engage in pica do not experience any adverse effects, especially when the behavior lasts for a short time.

Adverse outcomes are usually related to repeated ingestion over time; however, a few craved items may be immediately toxic. For example, ingestion of coffee grounds can cause caffeine toxicity, and ingestion of cigarette filters can cause acute nicotine toxicity. Ingestion of a small volume of bleach typically causes nausea and vomiting before causing more serious harm, but concentrated products (eg, Ultra Bleach) may cause internal burning. Sniffing highly concentrated chemicals in solvents or aerosols can be lethal.

Anemia — Pica is often associated with anemia (eg, primarily iron deficiency, but also hemolytic secondary to toxin consumption). In large meta-analyses evaluating the association between pica behavior in pregnancy and anemia or low hemoglobin/hematocrit, pica behavior was associated with a twofold increase in anemia (odds ratio 1.92, 95% CI 1.68-2.19, 23 studies) and 0.55 g/dL lower hemoglobin levels (table 1) compared with no pica behavior [6,23]. Similar relationships have been observed in nonpregnant populations [6,9,23]. Consequences of anemia are discussed separately. (See "Anemia in pregnancy".)

Inadequate or excessive gestational weight gain — If the individual's nonfood consumption (eg, earth, ice) significantly displaces consumption of caloric items, they may have low gestational weight gain. On the other hand, the consumption of large quantities of items high in calories, such as cornstarch and laundry starch (amylophagy), has been associated with both excessive weight gain and poor blood glucose control (in individuals with diabetes) [10]. One box of cornstarch contains approximately 1600 to 1700 kcal, and some individuals report eating up to two boxes per day [26]. Consequences of inadequate and excessive weight gain are discussed separately. (See "Gestational weight gain", section on 'Relationship between gestational weight gain and pregnancy outcome'.)

Micronutrient and trace mineral deficiencies — Micronutrient deficiencies can develop if the individual's nonfood consumption significantly reduces consumption of nutritive items or the item prevents absorption of micronutrients. For example, clay can induce satiety due to substantial swelling of the clay when exposed to gastric fluids [27]. Clay can also prevent absorption of micronutrients by binding with micronutrients in consumed food or forming a matrix with the mucin layer of the gut, thereby creating a barrier [1]. In vitro data suggest that iron can be bound by clays [28]. However, in animal studies, daily consumption of smectite-containing clay from Uganda had no negative effects on the animal's iron status, and the consumption of this earth may have provided a small amount of bioavailable iron [29]. Whether a negative effect would have been seen with higher, more physiologic doses is unclear.

There are no data on clay consumption affecting the absorption of other micronutrients. In one meta-analysis, pica behavior in mixed populations (pregnant and nonpregnant) was associated with lower plasma zinc levels compared with no pica behavior, but the difference was not statistically significant after exclusion of outliers (95% CI -48.20 to 8.93 mcg/dL) [23]. Consequences of deficiencies of trace elements are discussed separately. (See "Overview of dietary trace elements".)

Reduced effectiveness of some medications — The concomitant administration of clays, starch, charcoal, and/or magnesium trisilicate (a common antacid) together with pharmaceuticals such as antibiotics [30], cardiac medications [31], and antimalarials [32] can bind these pharmaceuticals, rendering them less effective. In a study of interventions to manage ciprofloxacin poisoning, activated charcoal, kaolin, magnesium trisilicate, and raw starch (which are substances that may be consumed by individuals with pica) all bound significant quantities of ciprofloxacin in vitro [33].

Electrolyte abnormalities — Pica involving substances such as clay, baking soda or powder, calcium carbonate antacids, or sodium chloride can result in electrolyte abnormalities.

●Clay – Ingestion of clay can bind potassium in the intestine, leading to clinical sequelae of hypokalemia such as hypokalemic myopathy [34].

●Baking soda or baking powder – Ingestion of large amounts of baking soda (sodium bicarbonate) can result in metabolic alkalosis, with hypokalemia, hypernatremia, hypochloremia, and hypocalcemia, as well as rhabdomyolysis and cardiomyopathy [35,36]. Ingestion of large amounts of baking powder (sodium bicarbonate, potassium bitartrate, and starch) can cause hyperkalemia.

●Calcium carbonate antacid tablets – Nonpregnant individuals with a history of Roux-en-Y gastric bypass have been reported to ingest up to 40 to 50 calcium carbonate antacid tablets per day, providing 10,000 mg calcium [37], which can cause symptoms related to hypercalcemia. (See "Clinical manifestations of hypercalcemia".)

●Sodium chloride – High sodium chloride intake can lead to calcium stone formation due to both sodium and calcium excretion as the kidneys attempt to maintain homeostasis. In one report, an individual with pica who consumed multiple spoonfuls of salt daily developed recurrent calcium nephrolithiasis [38].

●Ice – Pagophagia, or consuming large amounts of ice (ie, multiple bags/day), can cause polyuria (possibly made worse with desmopressin use), resulting in severe hyponatremia, altered mental status, and seizures [39,40].

Hypertension, edema — Individuals who ingest large amounts of sodium-containing substances (eg, baking soda, baking powder, table salt, some types of toothpaste) can develop high blood pressure and edema, which may mimic preeclampsia [41].

Gastrointestinal disorders — Pica involving a variety of substances can result in gastrointestinal disorders.

●Inflammatory disorders – Ingestion of laundry detergent can cause esophagitis and gastritis [42].

●Obstructive disorders – Ingestion of large amounts of clay, cloth, polyurethane foam (eg, mattresses, cushions), hair, paper/cardboard, and uncooked rice and wheat has been associated with abdominal discomfort, constipation, and intestinal obstruction, sometimes from formation of bezoars [43-51]. Bowel perforation has been reported, with at least one case of maternal death [43,52,53].

Exposure to toxins — Some substances ingested by individuals with pica are toxic, even in small quantities.

●Consumed earth may contain toxic contaminants, such as lead [54-61], arsenic [56,61,62], mercury [56,63], cadmium [56,62-64], nickel [61], manganese [22], aluminum [22], organic pollutants [65], or herbicides [66]. Lead has been found in a number of nongeophagic pica items, including paint chips, chalk, pottery glaze, and ink on printed paper [5,57,67]. Paper can also be a source of mercury poisoning [68]. Talcum powder toxicosis has been reported from consumption of talc-based powder [19].

●Excessive consumption of fluoride-containing toothpaste can cause fluoride toxicity, including fluorosis (change in the appearance of the enamel of unerupted teeth) in offspring [69]. (See "Overview of dietary trace elements", section on 'Fluoride' and "Preventive dental care and counseling for infants and young children", section on 'Fluorosis'.)

●Ingestion of mothballs, which are made of naphthalene or paradichlorobenzene, can cause fetal/newborn methemoglobinemia, hypotension, hemolytic anemia, and hyperbilirubinemia; other hepatic, renal, and respiratory complications; and maternal toxicity [70-72]. Naphthalene metabolites may also cross into the breastmilk, with levels higher than maternal levels.

●The head of safety matches is made of potassium chlorate, mixed with sulfur, fillers, and glass powder. In one report, maternal consumption of 300 burnt matchstick heads per week resulted in neonatal hemolysis, hepatic injury, and hyperbilirubinemia due to exposure to high levels of potassium chlorate [73].

Exposure to infection-causing organisms — Individuals with geophagy are at increased risk for a variety of infections. Geophagic samples originating in Africa but sold worldwide have tested positive for both aerobic bacteria and fungi [55]. A case report from the United States (Florida) described a sickle cell pain crisis and subsequent Pantoea species sepsis in a pregnant individual who had frequently consumed a large amount (at least 1 cup at a time) of potting soil for years. They had previously baked it but stopped doing so one week before admission [74]. However, nosocomial infection could not be excluded.

Consuming earth could also lead to geohelminth infections (eg, Ascaris lumbricoides) in areas of high geohelminth prevalence [67,75]. However, geophagy has not typically been associated with higher geohelminth burdens in these settings because of the preparation (baking, sun drying) and sources of geophagic soils (typically from areas where animals cannot tread) [55,76].

In the United States, geophagy can be a vector for Toxoplasma and Toxocara transmission [77], as well as soil-transmitted helminths (eg, Ascaris lumbricoides; Trichuris trichiura [whipworm]; Ancylostoma duodenale and Necator americanus [hookworm]). (See "Toxoplasmosis and pregnancy" and "Toxocariasis: Visceral and ocular larva migrans" and "Ascariasis" and "Hookworm infection" and "Enterobiasis (pinworm) and trichuriasis (whipworm)".)

Geophagy may also be a vector for toxigenic bacteria (Clostridium perfringens, Clostridium tetani, and Clostridium botulinum), potentially causing gas gangrene, tetanus, and botulism [78].

Oral conditions — Consumption of very hard substances, such as ice [79,80] or uncooked rice and wheat [50,81], may cause jaw pain or tooth/denture damage.

Adverse effects on offspring — Adverse maternal effects of pica behavior likely mediate any adverse effects of pica on offspring health. However, toxic substances consumed by the mother can directly impact the fetus and infant. For example, toxin-induced hemolytic anemia has been described, and instances of neonatal lead poisoning, attributable to maternal pica, have been reported [82,83]. In addition, maternal geophagy has been associated with both infant geophagy and poor child gross motor function [84]. (See 'Exposure to toxins' above.)

CLINICAL APPROACH

Identifying patients with pica

Our approach — We ask all pregnant patients about pica at their first prenatal visit as part of a standard dietary history and ask again in each trimester, rather than just asking patients in populations where it is more prevalent (see 'Epidemiology and course in pregnancy' above). Early universal assessment can identify patients engaged in a potentially harmful practice that may be treatable. Early discussion can also make it easier for the patient to disclose this to a health care provider if pica develops later in pregnancy. We follow up in the late second or early third trimester when the incidence of iron deficiency anemia increases and when patients may have developed a more trusting relationship with their provider [85].

Asking about pica is also appropriate at any time for patients newly diagnosed with anemia, iron deficiency, or symptoms that may occur from consumption of substances not culturally defined as food, especially if other causes of these symptoms have been ruled out [23,54]. While definitions of non-foods in the dominant culture can be used as a starting point for asking about nutritional intake, the beliefs and practices of the individual should be considered as well (ie, cornstarch may be considered a food item) [86]. (See 'Possible consequences' above.)

Identifying pica behavior only involves asking a few additional questions as part of the routine medical, dietary, or social history. We have had good success by asking, "Do you crave anything that is not food, like dirt, clay, paint, or lots of ice?" This approach may be more likely to achieve a truthful answer than asking if they have ever eaten such things. If pica is suspected, asking "How much earth, clay, paint, ice, etc have you eaten?" may be useful, as it makes the initial admission of pica unnecessary.

Asking about pica, including the reaction to reported consumption of nonfood substances, should be done with sensitivity, within the context of "this is commonly seen," along with offering appropriate treatments. Patients disclosing their pica behavior should be treated with respect, and pica should be treated as a normal, common occurrence during pregnancy [15]. Reacting with alarm will more likely reinforce the temptation to keep pica hidden.

Benefits and harms — Once patients share that they have cravings and/or have consumed the craved items, they may feel a great deal of relief and provide a substantial amount of information about their behavior.

Identification of pica behavior and initiation of harm reduction strategies can improve maternal and offspring outcome. In addition, asking about cravings early in pregnancy may prompt the patient to spontaneously disclose potentially harmful cravings that occur later in pregnancy. (See 'Possible consequences' above and 'Management' below.)

Patients are often reluctant to admit to pica for a wide range of reasons, including embarrassment, fear of repercussions from family or health care providers, and fear of accusations about harming themselves or their fetus [5,87]. We have had patients deny eating earth even when a smudge of clay was evident on their lips and tongue. If the clinician reacts with surprise or strongly negative responses, the patient may choose not to fully disclose ingestion of a potentially harmful substance at the time of screening or spontaneously later in pregnancy, and asking the questions will have caused more harm than good.

Establishing the scope of the behavior — We suggest obtaining the following information to better understand the behavior, determine if pica may lead to an adverse outcome, and guide the choice of interventions for reducing the behavior. A dietitian can be helpful in obtaining this information.

●Description of pica substance(s).

●What prompts the craving? Many individuals say that their mouth waters when they see the substance or think about eating it. Craving is often stimulated by the organoleptic property (ie, taste, texture, or smell) of the substance [12,70,88,89]. Other factors that may prompt cravings include temperature (usually cold), memories, habits, and recommendations by others [13].

●Duration of pica. Was it present before pregnancy? If not, at what gestational age did it start? Is there a history of pica in previous pregnancies? How do the cravings during this pregnancy compare with the last pregnancy?

●Concurrent symptoms. Is it associated with nausea and vomiting of pregnancy? Is it associated with ptyalism? Is it associated with signs and symptoms of iron deficiency anemia? (Iron deficiency manifesting as olfactory cravings has been termed desiderosmia [90]). If they are craving the taste of something, has their perception of that taste changed? Impaired taste or smell may be associated with zinc deficiency [91,92].

●Frequency of cravings.

●Strength of cravings. Can the craving be resisted? This may help distinguish between food cravings due to pregnancy versus those due to pica [93]. With pica, the craving is often specific and so strong that it is difficult to resist. For example, patients will not say "I want sweets" or "I feel like having pickles and ice cream." Instead, they will say "I want XXX brand of chalkboard chalk" or "I have to drive out of my way to go to XXX restaurant to get the crushed ice because I like how it crunches." Language commonly used for drug or alcohol addiction is quite common.

●Frequency of actual consumption and the amount consumed. If they are craving something but not consuming it, why not? Are they avoiding it or substituting something else for it?

●Source and availability of the substance. Patients may import their favorite soil from "home" [55,65]. Kaolin and other types of clay can also be ordered from online venders. If their desired substance is unavailable, what are they substituting for it? For example, patients from Mexico commonly use blocks of magnesium carbonate ("terrón de magnesio") as a substitute for earth because it is thought to be safer, although concerns have been raised about potential magnesium toxicity [12,94].

●Family observations. Does the family know? Are they concerned? Sometimes family members are supportive of pica; other times, they try to stop the behavior. We know of patients who have requested that their family members bring them soil from a particular spot but tell the family it is for plants rather than for consumption. Family members may note holes in the wall of the home, even if the patient will not admit to eating the adobe block or the plaster.

●Additional substances. Once a patient shares that one item is craved, it is important to ask about other cravings. The patient may test the clinician's reaction to craving one substance before discussing additional cravings. Those additional cravings may be the ones that are more concerning to the patient.

The physical examination is generally normal, but signs of poisoning or complications from ingesting a harmful substance may be present [95]. In particular, the clinician should assess for signs/symptoms related to anemia and for abdominal symptoms.

In the United States, Poison Control (1-800-222-1222) can be contacted for guidance on investigating the effects of unfamiliar substances.

Laboratory evaluation and management of abnormalities

●Hemoglobin/hematocrit – Pica is strongly associated with iron deficiency and anemia, so hemoglobin/hematocrit levels should be checked. All pregnant persons are routinely tested for anemia at least twice in pregnancy; additional testing is unnecessary in those with normal results unless symptoms appear and/or pica is a new occurrence.

In patients with pica and uncomplicated anemia, iron deficiency can be presumed, and the patient can be treated with iron empirically for one month and then retested (see "Anemia in pregnancy", section on 'Treatment of iron deficiency'). If anemia does not improve, further evaluation is warranted. (See "Diagnostic approach to anemia in adults".)

Iron supplementation from food or pharmacologic sources generally corrects iron deficiency anemia but does not consistently reduce pica. (See 'Treatment of the underlying cause' below.)

Additional laboratory testing is guided by the patient's pica cravings and associated symptoms. For example:

●Lead – Patients who are consuming any substance that may contain lead should have blood lead levels assessed. Those with elevated levels should be counseled about potential harmful effects, monitored, and managed appropriately. The substance itself can also be analyzed for lead content. Manifestation of acute toxicity may include abdominal pain, joint/muscle aches, fatigue, decreased libido, headaches, difficulty concentrating, short-term memory deficits, and irritability. Additionally, long-term exposure may produce anemia, decline in neurocognitive function, lead nephropathy, tremor, and hypertension. (See "Lead exposure, toxicity, and poisoning in adults".)

●Earth – Patients who consume earth should have a basic metabolic panel since they are at risk for electrolyte abnormalities. Testing for parasitic infections is reasonable in patients with suggestive symptoms [95]. A stool ova and parasite examination can also be considered, although the risk of parasitic transmission through most geophagic samples is low [55,76].

We do not check zinc levels routinely, given the low prevalence of zinc deficiency in the United States, even among vegetarians who tend to consume less zinc (meat is high in zinc) and more zinc binders (eg, phytates) [96]. Uncertainty about laboratory assessment of zinc status, especially during pregnancy, is another drawback to checking levels [97]. However, pica has been associated with low plasma [23] and low erythrocyte [98] zinc levels. Zinc laboratory tests may be considered where zinc deficiency is more common.

Management — Our approach to management of patients with pica is based on published observational data and our extensive clinical experience in this area. There are no evidence-based guidelines on the treatment of pica. In the only randomized placebo-controlled trial, iron supplementation of children with geophagy did not reduce the prevalence of the behavior nor the amount of earth eaten by the children, although this trial was limited by poor compliance and high dropout rates [99].

The four key components of management are:

●Understanding and reassurance, which will help to maintain communication, build trust, and gain the patient's willingness to accept and adhere to a treatment plan.

●Identifying the substance(s) consumed.

●Initiating a harm reduction strategy by decreasing exposure to the item craved or substituting a healthier alternative that will satisfy the craving. Simply telling the patient not to eat the craved item will not work and will likely result in hiding continued consumption. Referral to a dietitian can be helpful.

●Concurrent treatment of the underlying cause of the craving, whenever possible.

Provide understanding and reassurance — To build trust and enhance communication, it is critical for the clinician to show understanding. Speak the patient's native language, take the time to ask questions and listen to answers, and reinforce the concept that pica is very common (ie, they are not alone in these cravings and are not "crazy"). Ask about their experiences: Find out what they tried, when symptoms changed, if cravings stopped before or after they began to feel better, and about the substitutes that worked best. This often helps to get very good buy-in and adherence with clinical advice, as well as information to guide modifications in treatment if needed. These patients are often afraid, so letting them know that the condition can be treated is reassuring.

Identify the substance(s) consumed — After gaining the patient's trust, identifying the substance(s) the patient is consuming is critical for determining the potential adverse consequences (table 1) and management approach.

●Alarm substances – Consumption of highly toxic substances (eg, heavy metals) must be stopped immediately. In the United States, Poison Control (1-800-222-1222) is an excellent resource for assessing immediate danger. In these cases, informing patients that they are at high risk of seriously harming themselves and their offspring and offering a substitution may stop the behavior.

●Other substances – A less rigorous approach, as described below, can be taken for other cravings (see 'Initiate a harm reduction strategy' below). However, the risks associated with many substances are unclear since multiple factors affect maternal risk (eg, specific substance, quantity consumed), the substance may contain many unidentifiable contaminants, and information on fetal risk from these types of exposures is limited or nonexistent. For example, the safety of earth is highly variable. While some clays are used in pharmaceutical preparations (Kaopectate took its name from the clay kaolin, and smectite is used in a number of antidiarrheal preparations [1]), it is difficult to assess the safety of earth from unknown sources or to assess the actual amount and type of clay being consumed. Investigation of local sources of earth can be considered [100]. Some analyses of geophagic earth globally has been done. This can be a starting point but should not be the basis for treatment of an individual because the composition of earth can vary dramatically within even a few meters. Home sterilization of soil is not recommended because it may not kill all pathogens Home sterilization of soil is not recommended because it may not kill all pathogens [55] and would not remove harmful heavy metal contaminants.

Initiate a harm reduction strategy — Harm reduction strategies include:

●Substitution

●Decreased exposure

●Treatment of the underlying cause, when possible

We offer substitutions as the first-line approach for most patients, unless they seem willing to decrease or avoid consumption without other measures. Assume that patients are unlikely to decrease exposure if they are not clearly concerned about the safety of pica or if they express no interest in or perceived ability to decrease or eliminate the practice. Concurrently, treat the underlying cause, which may be iron and/or zinc deficiency.

Substitution — It is often (although not always) possible to find an acceptable alternative to the craved item that satisfies the organoleptic property (ie, taste, texture, or smell) that was initially alluring [90]. For example, for patients who crave wet earth, we suggest that they smell some wet earth as they eat a burned tortilla, toast, jicama, dry oatmeal, or any other substance that the patient thinks might be comparable in texture. Chewing ice can also be a good substitute for earth. Kaolin is a type of clay found in nature and also available commercially; food grade kaolin from a reliable source may be an acceptable substitute as well.

For patients who crave the crunch of cement, ice and Mexican hot chocolate disks can be successful substitutes. For those craving the sour taste of baking powder, sour hard candies have been successful. Chewing gum substitutes well for the rubber from tires, unless the patient is craving the smell of the rubber.

Decreased exposure — If the substance craved cannot be eliminated by substitution, then decreasing exposure can be useful. For example, patients who crave the smell of gasoline are asked to stand as far from the source as possible to minimize the inhalation of toxic substances. If they must go to a gas station to buy gas for their own car, they are asked to fill the tank completely so as to limit the number of trips that will be needed. They are also asked to avoid trips to the gas station with family and friends who are buying gas. For relatively nontoxic items (eg, cornstarch; bath, handwashing, or dish soap; chalk; napkins or toilet paper), some patients will be willing to reduce the quantities consumed after appropriate counseling. This counseling might include warning them that, while we do not have strong evidence of harm, we also do not know all of the components of the item and the effect these components might have on a developing fetus. Reassuring patients that we do not want to experiment on their child to learn about those problems helps them to resist the consumption of these substances.

Treatment of the underlying cause — Although clinicians generally want to identify and treat the underlying cause of pica, the cause is usually not known, and data on choice and efficacy of treatment are both scant and inconsistent. It is important to address the behavior itself as well as the cause since the behavior often has a cultural component and may be harmful, depending on the substance chosen. There are no evidence-based treatment guidelines. We take the following approach:

●If pica occurs early in pregnancy and is associated with nausea and vomiting or ptyalism (excessive secretion of saliva), implementing interventions to relieve those issues may also mitigate pica. Many patients attribute their pica cravings to attempts to relieve nausea and ptyalism. (See "Nausea and vomiting of pregnancy: Treatment and outcome".)

●Patients are referred to a mental health provider if a psychiatric disorder is suspected. Psychotropic medications, especially selective serotonin reuptake inhibitors (SSRIs), can be useful for treatment of pica in the limited situations where psychiatric comorbidity is present [49,68,101,102]. However, the underlying cause of new-onset pica in most patients in our practice is generally physiologic and cultural, which does not warrant psychiatric referral.

●Consuming foods high in heme iron and zinc (table 2) can lower pica cravings. Given that iron deficiency is common during any pregnancy, a practical approach is to preemptively advise patients to increase consumption of high iron foods that are acceptable and available while waiting for the results of the iron deficiency workup. They will often report the pica has resolved or improved (ie, cravings less often and/or less strong) by the next office visit.

If pharmacologic supplements are also needed, either oral or parenteral iron can be used [103,104]. Iron infusion was effective in resolving pica cravings within 36 hours when administered to a patient with iron deficiency (ie, low iron stores but hematocrit/hemoglobin still in the normal range) and esophagitis and gastritis secondary to laundry detergent consumption [42]. (See "Anemia in pregnancy", section on 'Treatment of iron deficiency'.)

No controlled studies have examined the effects of zinc supplementation alone on pica [1]. One observational study among pregnant patients in Argentina noted that those with pica reported diets significantly lower in zinc, heme iron, animal protein, and total meat intake [105]. However, total iron intakes were similar in both groups, and there was no difference in the use of vitamin-mineral supplements between the two groups.

Although iron deficiency is common in individuals with pica, whether iron deficiency causes pica or whether treatment of iron deficiency leads to improvement in pica remains unclear; controlled studies of the effects of iron supplementation on pica behavior have reported varying success [99,106-109]. The strongest evidence in support of iron deficiency causing ice pica (pagophagy) comes from a study in which anemic rats consumed a greater proportion of their daily water in the form of ice than nonanemic controls (96 versus 45 percent) [110]. Recovery from anemia eliminated this behavior. There are supportive human data as well [111], including the observation that pagophagy disappeared immediately when anemic patients were given intravenous iron [112]. Why iron deficiency is associated with pagophagy is unknown. However, there is evidence that chewing ice improves alertness and the response time on a neuropsychologic test for people who are anemic but not for others [113]. Various mechanisms have been proposed [20,113,114]. More research is needed.

Follow-up — During follow-up, determine whether the patient is still craving nonfood substances. If they are craving a substance, is the craving stronger or weaker than at the last visit? Are they eating the substance or resisting the cravings? Have other cravings appeared? Are the cravings dangerous? Are the patient's laboratory tests of iron status worse?

If cravings have subsided, reassure patients that they are on the right track. Patients may not realize that their behavior has changed. Family members of one patient noticed that she had stopped eating the ice out of all of their glasses before the patient herself noticed an improvement.

If their cravings have not improved or have worsened, reassure them again that they are normal and assess their adherence to previous recommendations. If they have not eaten heme-rich foods, reinforce the importance of resolving iron deficiency anemia for a healthy pregnancy and birth. If they have not tried substitutions, try to find out why and encourage them to try this approach. Investigate whether there are familial or cultural issues that are competing with medical advice. There have even been reports of verbal and/or physical abuse from family members when their advice to consume nonfoods is not followed [54] (see 'Refractory cases' below). If this is the case, we try to find a way to modify the situation. With patience and sensitivity, these situations can usually be resolved.

EFFECTIVENESS OF TREATMENT — Pica caused by iron deficiency appears to improve or resolve with iron therapy, particularly in patients with ice pica (pagophagy), but available data are limited to a few comparative studies and case reports. (See 'Treatment of the underlying cause' above.)

Pica related to strong cultural beliefs of benefit, or at least lack of harm, is unlikely to stop completely. While some authors report that the condition generally spontaneously resolves postpartum [95], this is not universally true [115-117].

Often, the frequency and focus of medical care change after giving birth, and patients are less likely to be consistently asked about pica. With continued consumption of foods high in heme iron and lack of menses for at least six weeks after giving birth, pica associated with iron deficiency will likely decrease over time. However, there are patients who will continue with pica as a habit.

REFRACTORY CASES — The best approach for patients who do not respond to the initial harm reduction strategy is probably to continue offering substitutions until one is found that enables them to ingest a potentially less dangerous substance that adequately satisfies their craving. In many cultures, satisfying pregnant persons' cravings is seen as important for their well-being and that of the fetus [87,118,119].

There are a broad range of beliefs that may prevent patients from stopping their nonfood consumptions. Some patients view pica as neither harmful nor helpful, simply a normal sign of being pregnant [120], a means of satisfying the fetus's craving [119], or a way of making the fetus happy [12,87]. It may also be used as a way of gaining attention and support during pregnancy and the postpartum period [118], and it may provide a sense of community or a continuity of lineage [115,121]. Some patients feel that there are health benefits of nonfood cravings, but these benefits are largely unproven [1,54,62,87,118-120,122-127].

Other patients either experience the cravings so strongly or enjoy the consumption of nonfood items so thoroughly that they are simply unable to ignore them, even after hospitalization [36]. They may describe the craving in a way similar to that of those with substance use disorder who crave alcohol or cocaine [5].

Finally, some patients may be afraid of not consuming what they crave because of fear that something will be missing from the newborn, it will have a birthmark (possibly in the shape of the unfulfilled substance), or it will be born with its mouth open because of unsatisfied needs [12,54,87,120]. Some have expressed concern that not acting on the craving will lead to an illness, difficult labor, or fetal loss.

SUMMARY AND RECOMMENDATIONS

●Diagnosis

•The diagnosis of pica is based on an individual's report of craving and intentional consumption of substances not culturally defined as food (eg, earth, clay, starch, ice, paper). (See 'Diagnosis' above.)

•A reasonable approach to identifying pregnant patients with pica is to routinely ask "Do you crave anything that is not food, like dirt, clay, paint, or lots of ice?" The scope of behavior (eg, substance craved, amount consumed, triggers) should be ascertained in patients who have positive responses to these questions. (See 'Identifying patients with pica' above and 'Establishing the scope of the behavior' above.)

●Epidemiology – Pica occurs in all populations. The prevalence is higher in pregnant persons and among people from sub-Saharan Africa, the Southeastern United States, the Indian subcontinent, and Latin American populations. Medical disorders associated with pica include iron deficiency, zinc deficiency, unspecified anemia, celiac disease, and renal dialysis. (See 'Epidemiology and course in pregnancy' above.)

●Prognosis – The consequences of pica depend on the type and quantity of substances being consumed and whether toxins have contaminated these substances (table 1). (See 'Possible consequences' above.)

●Evaluation – Laboratory tests should be guided by the patient's pica cravings and associated symptoms. Pica is strongly associated with iron deficiency and anemia, so hemoglobin/hematocrit levels should be checked. (See 'Laboratory evaluation and management of abnormalities' above.)

●Management – The four key components of management are (see 'Management' above):

•Understanding and reassurance, which will help to maintain communication, build trust, and gain the patient's willingness to accept and adhere to a treatment plan.

•Identifying the substance(s) consumed.

•Initiating a harm reduction strategy by decreasing exposure to the item craved or substituting a healthier alternative that will satisfy the craving. Simply telling the patient not to eat the craved item will not work and will likely result in hiding continued consumption. Referral to a dietitian can be helpful.

•Concurrent treatment of the underlying cause of the craving, whenever possible.