PATTERNS OF EVOKED BEHAVIOR IN TWIN PREGNANCIES DURING THE FIRST 22 WEEKS OF GESTATION

The objective of this work was to investigate the emergence of intrapa ir stimulation between twin fetuses and the presence of possible chang es in types and percentage of evoked patterns with advancing gestation al age. The existence of intrapair stimulation would indicate the func tioning of fetal tactile and proprioceptive sensibility. This was stud ied from video recordings of 30 min ultrasonographic observations of 8 twin pregnancies at 8, 9 and 10 weeks gestational age, of 20 twin pre gnancies at 11,12 and 13 weeks and of 20 twin pregnancies studied with 60 min observations at 15-16, 18-19 and 21-22 weeks. All age groups w ere subdivided in Monochorionic (Me) and Dichorionic (De) pregnancies. Intrapair stimulation before 11 weeks gestational age is an exception al event. Due to greater spatial contiguity and thinness of the membra ne dividing the two amniotic sacs in Me pregnancies, it was noted only in these. From 12 weeks onwards, evoked movements began to be observe d in Dc pregnancies as well. After the 15(th) week, intrapair stimulat ion is a constant and increasing feature of all twin gestations. Movem ents vary from generalized bodily activity to being progressively loca lized. No specific evoked movement patterns were observed. (C) 1997 El sevier Science B.V.