Pregnant women often complain of lack of concentration and poor memory. Scientists now offer an interesting explanation for this phenomenon; that a woman's brain size shrinks during late pregnancy and it takes up to six months to regain its full size. Using magnetic resonance imagery, Anita Holdcroft and her colleagues at the Royal Postgraduate Medical School in London, scanned the brains of 10 healthy pregnant women. The three-dimensional images of the brains revealed a decrease in their sizes during late pregnancy; the brains returned to their normal sizes within some months after delivery. Researchers linked this with the cognitive problems experienced by the mothers-to-be and the new mothers. They however, feel that the changes in the brain are due to changes in the volume of individual cells, rather than changes in the number of cells in the brain. Interestingly, the pituitary gland at the base of the brain, which releases a wide range of hormones, including some responsible for regulating reproduction, increases in size during pregnancy (New Scientist, Vol 153, No 2064).