Individual growth curve standards in twins: prediction of third-trimester growth and birth characteristics.
The ability of Rossavik growth models, determined from measurements obtained before 24 weeks, to predict third-trimester growth and birth characteristics in normally growing twins has been investigated. Third-trimester values for head circumference, abdominal circumference, and femur diaphysis length were predicted with an accuracy of +/- 6% to 9% (95% to 98% of percent deviations). For thigh circumference and estimated weight, the comparable values were +/- 15% and +/- 16%, respectively. The head circumference at birth was predicted without bias; the random error was approximately +/- 5% (94% of percent differences). Weight, abdominal circumference, and thigh circumference were systematically overestimated (3.1%, 14.9%, and 11.3%, respectively) as a result of differences in prenatal and postnatal measurement procedures. After correction for systematic errors, these parameters could be predicted with random errors of -11.5% to 7.2% (weight), -12.8% to 5.4% (abdominal circumference), and -15.3% to 10.0% (thigh circumference). Growth Potential Realization Index values were found to have means of approximately 100% and ranges from 91% to 118%. These results are similar to those for singletons and indicate that individual assessment of growth in twins can be carried out with the same methods used for singletons.
Stefos
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Department of Obstetrics-Gynecology, Baylor College of Medicine, Houston, TX 77030.
Deter
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RL
Hill
R M
RM
Simon
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NV
D000328:Adult; D000886:Anthropometry; D005314:Embryonic and Fetal Development; D005260:Female; D005544:Forecasting; D006801:Humans; D007231:Infant, Newborn / Q000502:physiology*; D011247:Pregnancy; D011263:Pregnancy Trimester, Third; D012016:Reference Values; D014427:Twins