The effect of the increasing prevalence of maternal obesity on perinatal morbidity

OBJECTIVE: in this study, we assessed the temporal trends and relative and attributable perinatal risks of maternal obesity over a 20-year period. STUDY DESIGN: We conducted a retrospective cohort study between 1980 and 19 99 by using a computerized perinatal database of all women who received pre natal care and delivered their Infants within a regional health care system . The main outcome measures were as follows: (1) annual mean body weight an d the percentage of women classified as obese at the first prenatal visit ( primary definition greater than or equal to 200 lb; secondary definitions g reater than or equal to 250 lb, greater than or equal to 300 lb, body mass index > 29 kg/m(2)); and (2) relative and attributable risks of obesity for selected maternal and perinatal morbidities in successive 5-year periods. RESULTS: From 1980 to 1999, the mean maternal weight of women at the first prenatal visit increased 20% (144-172 lb), as did the percentage of women g reater than or equal to 200 lb (7.3-24.4), the percentage greater than or e qual to 250 lb (1.9-10.7), the percentage greater than or equal to 300 lb ( 0.5-4.9), and the percentage with a body mass index > 29 kg/m(2) (16.3-36.4 ), P < .01 for all. Controlling for maternal age, race, and smoking status, obese women were at Increased risk at each period for cesarean delivery (r ange of adjusted relative risk,,1.5-1.8), gestational diabetes (range, 1.8- 2.9), and large (> 90th percentile) for gestational age infants (range, 1.8 -2.2). From the earliest 5-year period (1980-1984) to the most recent (1995 -1999), the percentage of obesity-attributable cesarean deliveries more tha n tripled from 3.9 to 11.6. Similar percentage increases were observed for the obesity-attributable risks for gestational diabetes (112.8-29.6) and la rge for gestational age infants (6.5-19.1). Trends for secondary obesity de finitions were similar, although the magnitude of the increased attributabl e risks was smaller. CONCLUSIONS: Efforts to reduce the frequency of certain perinatal morbiditi es will be constrained unless effective measures to prevent, or limit the r isks of, maternal obesity are developed and implemented.