Objective: Our purpose was to evaluate factors associated with the best intrauterine growth and lowest morbidity among twins ("ideal twin pregnancy").
Study design: A historic prospective study of 163 twin births was performed. Ten models were formulated with multiple regression and multivariate logistic regression.
Results: In the models of birth weight, gestations of 28 to 36 and 39 to 41 weeks, black race, > or = 15% discordancy, and smoking were all significant negative factors. The pattern of early low weight gain (< 0.85 pounds per week before 24 weeks) and late low weight gain (< 1.0 pound per week after 24 weeks) was negatively associated with all eight models of intrauterine growth.
Conclusions: The best intrauterine growth and lowest morbidity is achieved earlier for twins than for singletons. Using length of stay and growth retardation criteria, nearly 70% of "ideal" twin pregnancies were between 35 and 38 weeks. In addition, poor weight gain and poor patterns of weight gain were associated with all measures of intrauterine growth and adverse pregnancy outcomes.