Sonographic growth measurements in triplet pregnancies.

Sonographic growth curves of biparietal diameter (BPD), head circumference, abdominal circumference, head circumference/abdominal circumference ratio, and femur length were generated from 24 uncomplicated, concordant triplet pregnancies. These were compared with the standard curves derived for singletons used in our medical center. Slowing of BPD, head circumference, and abdominal circumference growth was noted in triplets from the 28th week of gestation, whereas the head circumference/abdominal circumference ratio was similar to that of singletons. Femur growth was parallel to that of singletons, although on the low margin of the two standard deviations. We conclude that the growth patterns of triplets are different from those of singletons. We suggest that femur length derived for singletons may be suitable for the follow-up of triplets. However, when growth retardation is suspected, the growth curves presented herein may be used to identify the growth-retarded fetus.