Purpose: to study the influence of weight differences between twins on the perinatal results. Methods: the twin deliveries at the Maternity of the Hospital Regional de Clínicas de Sorocaba, SP, were retrospectively analyzed from July 1997 to June 1998. The samples were 89 mothers and their twins, divided into three classes of newborn weight differences, as follows: concordant (<15%), mild discordance (15 to 25%) and severe discordance (>25%). The independent variables analyzed were these three classes and the dependent variables were low weight at birth, Apgar index less than 7 at the first and fifth minute, premature delivery, time of permanence of the newborn in the nursery, and perinatal mortality coefficient I. Statistical analysis was performed using Kruskal-Wallis test, completed by Hollander test, and the Blackwell test. Results: the number of pregnancies (62, 17 and 10) and premature deliveries (32, 9 and 7) were observed respectively in the three classes. For the first and second twins we observed: low weight at birth (39/41, 13/12 and 8/9), Apgar index less than 7 at the first minute (16/13, 3/7 and 2/3), Apgar index at the fifth minute (4/4, 0/2 and 1/2), time (in days) of permanence of the newborn in the nursery (3.7/3.7, 4.6/6.0 and 7.3/8.7) and perinatal mortality coefficient I (22.4/16.8, 0/16.8 and 5.6/5.6). Conclusions: the incidence of weight discordance between twins was 30.3%, 19.1% being mild discordance and 11.2% severe discordance. There was a tendency to a progressive aggravation of perinatal results considering the degree of discordance of the classes (concordant < mild discordance < severe discordance).
Twins; Discordant twins; Perinatal morbidity and mortality
