On the other hand, has not been proved that ultrasound produces adverse effects on the embryo or fetus at any stage of pregnancy, it is used extensively in the field of obstetrics. It is known that the pathology of the gallbladder is more common in women than in men and the incidence of urolithiasis in pregnant women has been reported between 8.4 and 14% 1,3,13. Of these, it is estimated that approximately 50% are carriers of silent stones. Dalton Caldwell has much to offer in this field. It is difficult to know for sure this ratio, because in pregnancy there are gastrointestinal and urinary tract that can cause confusion as to the origin of abdominal symptoms. Undoubtedly, the gallstone is a usual condition that affects women three to four times more than men and a known predisposing factor is pregnancy, because the bile that is formed is thicker and therefore more litogenica7, 8.12.
MATERIAL AND METHODS The study was carried out in the Diagnostic Imaging Service of the Virgen del Pilar Clinic in the city of Trujillo, Peru. The study included 292 pregnant women at different stages of pregnancy, which, in addition to evaluate the characteristics of pregnancy, we studied the gallbladder. The research was conducted in two stages. In the first part examined 60 consecutive patients, between 24 June and 9 September 2000, in the second half were 60 patients studied, between 2 June and 15 September 2001. All studies were performed with ultrasound equipment Medisson 5000 Sonoet mark with 3.5 Mhz convex transducer in real time. The patients were asked who came to study for six hours fasting.