Pregnant women often have strange food cravings and aversions, and are sometimes affected by eating perversions or pica.
Pica is a compulsion for persistent ingestion of unsuitable substances that have very little or no nutritional value, according to Krause (2000). Some authors estimate that between 8% and 65% of pregnant women suffer from pica – an eating aberration that's linked to iron-deficiency anaemia (Lopez et al, 2004).
Why does it happen and, more importantly, what can you do to prevent your cravings for inedible substances?
Food cravings and aversions
Pregnant women are known for waking up in the middle of the night and sending their husbands out to go and buy anything from pickled herrings to strawberries to chocolate cake. No one knows why this happens, but generally these eating aberrations aren't harmful if not practised to excess.
Most women make changes to their diet when they fall pregnant. Some changes are for the better and are based on advice from their doctors or dieticians. Women who may have been eating a diet based on junk food may decide to make a change for the better by eating a balanced diet rich in protective nutrients for the sake of their babies.
Despite the fact that we're now living in the 21st century, many women still adhere to old-fashioned beliefs when it comes to eating during pregnancy. They avoid foods like eggs, meat, milk, pork and liver, to name but a few. Such avoidances are, of course, detrimental to the health of both the mother and child.
Whenever possible, a pregnant woman should seek advice from her doctor or dietician if she is practising an illogical eating habit. Ask the experts if eggs are harmful during pregnancy (they are not!) and start eating these foods again if you have been given sensible advice.
Just because your grandmother or a tribal tradition bans pregnant women from eating eggs, doesn't mean that this practice is either sensible or healthy. (Just always make sure that your eggs are properly cooked or buy pasteurised eggs, which are now available at Checkers stores in Gauteng and Cape Town.)
Avoiding 'excessive weight gain'
Many women erroneously believe that they should avoid gaining weight during pregnancy in the mistaken belief that a small, underweight baby will be easier to deliver. This is a fallacy.
You need to gain a certain amount of weight during pregnancy to ensure that your baby develops properly. If you start your pregnancy with a normal body weight, then it's important to allow your body and the developing foetus and placenta to increase in weight by 11.5 to 16kg.
Underweight babies are more prone to foetal death and developmental setbacks than normal-weight babies. So while it's important not to gorge while you're pregnant and gain 20 or 30kg, a moderate gain of about 16kg will ensure that your baby has the best chance in life.
Pregnancy is not the time to be figure-conscious. Once the baby is born, you'll lose weight during the birth and shed the last few kilos if you follow a sensible diet, breastfeed your baby and go for walks every day.
Pica or "perverted eating" is a strange phenomenon where pregnant women start eating totally unsuitable and non-nutritious items on a regular basis.
Examples include so-called geophagia, which is characterised by eating soil or clay, or amylophagia, where women eat vast quantities of starch, including laundry starch. Other non-food substances such as ice (pagophagia), paper, burnt matches, stones, charcoal, soot, cigarette ash, antacid tablets, milk of magnesia, baking soda or bicarb, and coffee grounds, may also be eaten regularly and in excessive amounts.
This bizarre eating behaviour is, of course, highly detrimental to the health of the mother and child, and can in some instances be very dangerous (for example, eating stones can damage the teeth, pica can cause lead and other heavy-metal poisoning or expose the mother and child to the risk of infections caused by pathogens or worms found in soil, etc).
The most serious consequences of pica are:
- replacement of nutritious foods by non-food items leading to deficiencies and malnutrition (for example, iron-deficiency anaemia);
- obesity caused by ingestion of massive quantities of starch or sugar;
- exposure to toxic compounds such as heavy metals (e.g. lead in paint) which can poison the infant and the mother;
- exposure of the mother and child to helminthic or other infestations (Rose et al, 2000);
- interference with the absorption of essential minerals, especially iron, calcium and zinc;
- intestinal obstruction if large quantities of clay or starch are eaten.
Possible causes of pica
Pica has been described since the times of the Greeks and Romans (Lopez et al, 2004), but scientists are still not sure why pregnant women indulge in these aberrant eating behaviours.
One theory suggests that eating non-food items may counteract nausea and vomiting. While it is well known that eating a dry biscuit or rusk before getting up in the morning, or sucking a lemon or a piece of ice, can relieve nausea, there's no evidence that eating vast quantities of ice or paper or other non-digestible items will control nausea and prevent vomiting.
Another hypothesis states that pregnant women start eating soil or starch because they have an inherent deficiency of certain nutrients. This theory is based on the finding that people of all ages who suffer from severe iron deficiency tend to indulge in pica.
In certain parts of the world, where people follow very deficient diets based on a single staple food such as maize or wheat, pica is relatively common in the undernourished, iron-deficient population. However, most western women who are under the care of a doctor, gynaecologist, dietician or clinic, shouldn't develop deficiencies of iron, calcium or any other nutrient.
There are also other nutritionists who believe that pica is due to superstitions and customs passed from mother to daughter and that it doesn't have a physiological basis at all.
Research confirms that pica is more common in areas with a low socio-economic status and in women, particularly those who are pregnant (Rose et al, 2000).
Although there are a number of theories, no definitive conclusion has been reached that can explain why pregnant women eat inappropriate or foreign items such as clay or ice. A number of studies have attempted to pinpoint characteristics of women who indulge in pica:
- An American study (Edwards et al, 1994), investigated pagophagia (ingestion of large quantities of ice or freezer frost) in more than 500 pregnant African-American women. The researchers found that 8.1% of these women consumed between ½ and 2 cups of ice a day on 1 to 7 days a week. These pregnant mothers had significantly lower blood iron levels than mothers who didn't eat ice and the heads of babies born to the pica mothers were smaller than babies born to mothers who didn't indulge in pagophagia. The authors suggested that pagophagia may be a way of controlling stress in pregnant African-American women who don't have a well-organised social support structure.
- A South African study, conducted by Stein and coauthors in 1996, concluded that pica was an obsessive-compulsive disorder which could possibly be treated by prescribing serotonin re-uptake inhibitors. The latter treatment may, of course, not be advisable during pregnancy, so it's important to address pica before a woman falls pregnant.
- Another study carried out in Buenos Aires (Lopez et al, 2007) with 71 pregnant women with pagophagia and other forms of pica, indicated that these women had lower intakes of carbohydrates, animal proteins, bioavailable iron and zinc. Seeing that iron and zinc are regarded as “marginal nutrients” in pregnancy (in other words, many women tend to have low intakes of iron and zinc, particularly in less advantaged areas), Lopez and his team (2007) warn that doctors should be aware of this condition, which is more common than was previously believed. Early diagnosis is essential and this disorder should be prevented or corrected by providing pregnant women with counselling about healthy food selection and the use of iron, and if necessary, also zinc supplements.
What to do about pica
If you have pica, it's important to tell your doctor, dietician or clinic sister about this aberration. They will arrange for blood tests to determine if you are iron deficient or lacking in any other nutrient, so that you can supplement your diet with the missing vitamins or minerals.
It may take a great deal of discipline to stop eating these strange items, but it's vital to stop eating things that could be harmful or even poisonous – for your own and your baby's sake.
(Dr Ingrid van Heerden, registered dietician)
(Edwards CH et al, 1994. Pica in an urban environment. J Nutr, 124(6 Suppl):954S-962S; Krause’s Food, Nutrition, & Diet Therapy, 2000. Mahan LK & Escott-Stump S Eds. 10th Ed. WB Saunders Co, USA. Lopez LB et al, 2004. Pica during pregnancy: a frequently underestimated problem. Arch Latinoam Nutr, 54(1):17024; ; Lopez LB et al, 2007. Nutrient intake in women with pagophagia and other forms of pica during pregnancy). Nutr Hosp,22(6):641-7; Rose EA et al, 2000. Pica: common but commonly missed. J Am Board Fam Pract, 13(5):353-8; Stein DJ et al, 1996. Pica and the obsessive-compulsive spectrum disorders. SA Med J, 86(12 Suppl):1586-8, 1591-2.)