Objectives: To assess the effects of prescribing an antigen avoidance diet during pregnancy on the nutritional status of the mother and newborn and on the development of atopic disease in the child. The main focus is on women at high risk for giving birth to an atopic child, based on a history of atopic disease in the mother, father, or a previous child.
Search strategy: The register of clinical trials maintained and updated by the Cochrane Pregnancy and Childbirth Group.
Selection criteria: All acceptably controlled comparisons of maternal antigen avoidance prescribed to pregnant women at high risk, regardless of the degree of antigen avoidance (number of foods eliminated from the diet) or the time of its onset during pregnancy. Data are also included on formula-fed (ie non-breastfed) infants in trials of maternal antigen avoidance intended to continue beyond pregnancy into the lactation period.
Data collection and analysis: Data were extracted by the author from published reports, and supplemented by additional information from trialists contacted by the author.
Main results: Three trials involving 504 women were included. Based on the single trial providing pertinent data, the restricted diet was associated with a small but statistically significant lower mean gestational weight gain (mean difference = -3.0% of prepregnancy weight) and a nonsignificantly higher risk of preterm birth. The combined evidence does not suggest a strong protective effect of maternal antigen avoidance on the incidence of atopic eczema or asthma during the first 12-18 months of life. Data on allergic rhinitis/conjuctivitis and urticaria are limited to a single trial each and are insufficient to draw meaningful inferences. Two trials suggest a lower incidence of skin prick tests to egg at 6 months of age, but the effect was no longer evident at 18 months, nor was any benefit apparent at either age for skin prick tests to milk. If anything, cord blood IgE levels were higher in the experimental (antigen avoidance) group.
Reviewer's conclusions: Prescription of an antigen avoidance diet to a high-risk woman during pregnancy is unlikely to reduce substantially her risk of giving birth to an atopic child. Moreover, such a diet may have an adverse effect on maternal and/or fetal nutrition.