The objective of this study was to determine if exposing pregnant rats to RF fields during pregnancy affected the behaviour of there offspring at 3 months of age. Twelve rats were exposed continuously from days 1 to 20 of pregnancy to a low-level (0.1 mW/cm²) 900 MHz, 217 Hz pulse modulated EMF. This is similar to the highest legal exposure to the radiation of base antennas of the GSM digital cell-phone technology. The whole body average SAR ranged between 17.5 and 75 mW/kg. Another group of 12 rats was sham-exposed. Four pups (two of each sex) were selected from each litter for testing, which took place at 11-12 weeks of age. The food-reinforced lever-pressing activity and the inter-response intervals between consecutive lever presses were compared between exposed and sham-exposed animals. Analyses showed that exposure in utero to the GSM field did not induce any measurable cognitive deficits. The authors state that similar experiments should be done at substantially higher power densities.