THE ASSOCIATION OF PATTERN OF MATERNAL WEIGHT-GAIN WITH LENGTH OF GESTATION AND RISK OF SPONTANEOUS PRETERM DELIVERY

Monitoring weight gain during pregnancy may be useful in detecting pre gnancies that are at increased risk of early delivery. This study exam ines 7259 deliveries that occurred at the University of California, Sa n Francisco's Moffitt Hospital from 1980 to 1990. Obese women, women w ith diabetes or hypertension during pregnancy, deliveries with congeni tal malformations and non-spontaneous preterm deliveries were excluded . Pattern of gain was assessed by fitting a quadratic curve to each wo man's series of weight and date measurements, using simple regression techniques. The parameters from this curve were used to develop a vari able for pattern of gain that reflects how much an individual's patter n of gain differs from a linear pattern of gain. Multivariable linear and logistic regression analyses indicate that patterns of gain that d eviate greatly from the average pattern of gain (i.e. patterns that sh ow a marked speeding up or slowing down of gain towards the end of pre gnancy) are associated with significantly shorter gestational age and confer a significantly increased risk of spontaneous preterm delivery. The results suggest that monitoring weight gain during pregnancy is i mportant, although more specific studies are needed to understand the mechanisms by which weight gain pattern relates to preterm delivery be fore appropriate interventions can be developed.