EVALUATION OF TWIN GROWTH STATUS AT BIRTH USING INDIVIDUALIZED GROWTHASSESSMENT - COMPARISON WITH CONVENTIONAL METHODS

Objective: We sought to evaluate the growth status of twins at birth u sing individualized growth assessment methods and to compare this asse ssment with that obtained with conventional methods. Study design: Twe nty twin pregnancies were studied longitudinally with ultrasound. Meas urements of the head and abdominal cubes (A,B), head circumference (HC ), abdominal circumference (AC), thigh circumference (ThC), and femur diaphysis length (FDL) made in the 2nd trimester were used to specify Rossavik growth models for each parameter in each fetus. These models were used to predict weight (WT), HC, AC, ThC, and crown-head length ( CHL) at birth. Actual birth measurements made within 24 hours of deliv ery were compared to predicted values, the latter corrected using sing leton [corrects for both technical problems (TP)] or twin [corrects fo r both technical problems (TP) and decreased soft-tissue deposition (D STD)] correction factors where appropriate. Two sets of growth potenti al realization index (GPRI) values and their corresponding neonatal gr owth assessment scores (NGAS) were calculated and compared to previous ly established normal values. Birth measurements were compared with ap propriate population age-specific size curves. These data were used to characterize and classify the growth status of each twin neonate. Res ults: Individualized growth assessment identified five primary types o f growth outcomes: normal (Group I, 45%); primarily DSTD (Group II, 22 .5%); IUGR (Group III, 15%); above average soft-tissue deposition (Gro up IV, 5%); and growth acceleration (Group V, 7.5%). Within Group I wa s a subgroup with evidence of DSTD (Group Ib, 33.3% of Group I). Group II could be divided into two subgroups, one with only DSTD (Group IIa , 44.4% of Group II) and one with both DSTD and other growth abnormali ties (Group IIb, 55.6% of Group II). Group III had multiple growth abn ormalities which were more severe than those seen in Group II. All nor mal neonates were AGA and had virtually all anatomic parameters within their respective normal ranges. Of the neonates with definite evidenc e of IUGR (Groups IIb and III), only 4 of 11 (36.4%) were SGA and only 6 of 11 (54.5%) had any of the five anatomic parameters below their r espective normal ranges. Only 1 of 3 (33.3%) of neonates with growth a cceleration was LGA and none (0%) of the five anatomic parameters were above their respective normal ranges. Conclusions: Individualized gro wth assessment methods provide a more comprehensive assessment of grow th outcome in twins and detect a decrease in soft-tissue deposition no t identifiable with conventional growth assessment procedures. The lat ter procedures are also less sensitive in the detection of both IUGR a nd growth acceleration. (C) 1995 John Wiley and Sons, Inc.