Comprehensive fetal ultrasonographic growth measurements in triplet gestations

OBJECTIVE: Our purpose was to create tables and graphs of ultrasonographica lly derived fetal growth parameters in longitudinally studied triplet gesta tions from a single center. STUDY DESIGN: All triplet pregnancies managed by our division from 1987 thr ough 1998 were identified. All had first-trimester dating sonograms and com plete obstetric sonograms obtained by means of 3.5- or 5.0-MHz curvilinear transducers with freeze-freeze capability and on-screen calipers. Sonograms to assess fetal growth were obtained every 2 to 4 weeks, from 16 to 18 wee ks' gestation until delivery. Fetal parameters obtained with each sonogram included biparietal diameter; head circumference; bicerebellar diameter; ab dominal circumference; femur, humerus, tibia, and fibula lengths; estimated fetal weight; and head circumference/abdomlnal circumference ratio. Regres sion analysis was performed with JMP and Cricket Graph software packages, a nd lines of best fit with 95% confidence intervals were generated. RESULTS: A total of 443 ultrasonographic examinations were performed for 33 triplet pregnancies (99 fetuses), Each had between 3 and 6 sonograms obtai ned, ail between 16 and 35 weeks' gestation. Scatterplots of each of the fe tal growth parameters against gestational age were created with regression lines of best fit and 95% confidence intervals. All growth parameters were dependent on gestational age. CONCLUSION: A comprehensive set of fetal growth measurements in triplets fr om the United States is now available and can be used to assess longitudina l fetal growth.