Twin pregnancies: an 11-year review.

From 1971 to 1981, 16752 women were delivered at the University Women's Clinic in Heidelberg; 228 of these were twin pregnancies (1.36%). The relationships between sex, gestational age, birthweight, mortality, and fetal outcome were investigated. For the reason of grading, so-called chi 2 curves are used. These curves show the strength and the course of relationship between two parameters. Mortality of the twin (8.3%) depended on birthweight and on sex of the infant, but not on the mode of delivery. All twins were 'small-for-date' (25th weight percentile of single births). Starting at the 35th week of gestation, the increase in weight decelerated additionally. So, immaturity as well as twin-related factors led to the high mortality rate for twins. Fetal outcome was evaluated in respect to the birthweight and to the delivery interval.