G C Smith1. 1. Department of Biomedical Sciences, College of Veterinary Medicine, Cornell University, Ithaca, New York, USA.
Abstract
OBJECTIVES: 1. To describe the relation between birthweight and risk of emergency caesarean section at term; 2. to determine whether the relation between birthweight and caesarean section differed between male and female babies; and 3. to determine what proportion of the increased rates of caesarean section could be related to greater birthweights. DESIGN: Retrospective population study. SETTING: Data collected from Scottish Morbidity Record 1980 to 1996. POPULATION: All first singleton deliveries by emergency caesarean section and non-elective vaginal birth of live babies at 40 weeks of gestation (n = 120,854). MAIN OUTCOME MEASURE: Delivery by emergency caesarean section. RESULTS: There was a U-shaped relation between birthweight and the risk of caesarean section, with the lowest risk associated with weights in the range 3,000-3,500 g. Overall, male, were more likely to be delivered by caesarean section (relative risk = 1.2, 95% CI 1.2-1.3). The association between male sex and increased risk of caesarean section persisted after adjusting for birthweight, but only males weighing < 4,000 g were at increased risk of caesarean section compared with similarly sized females. Between 1980 and 1996, there were linear increases in the rate of caesarean section (from 7.1% to 10.7%, r2 = 0.8, P < 0.001) and median birthweight (from 3,360 g in 1980 to 3,420 g in 1996, r2 = 0.8, P < 0.001). The population attributable fraction of caesarean sections related to year of delivery 1981-1996 was not significantly altered by adjusting for birthweight (22.3% vs 21.6%). CONCLUSIONS: There is no evidence to suggest that increasing birthweights have contributed to increasing rates of caesarean section in Scotland between 1980 and 1996 among singleton first births non-electively delivered at 40 weeks of gestation.
OBJECTIVES: 1. To describe the relation between birthweight and risk of emergency caesarean section at term; 2. to determine whether the relation between birthweight and caesarean section differed between male and female babies; and 3. to determine what proportion of the increased rates of caesarean section could be related to greater birthweights. DESIGN: Retrospective population study. SETTING: Data collected from Scottish Morbidity Record 1980 to 1996. POPULATION: All first singleton deliveries by emergency caesarean section and non-elective vaginal birth of live babies at 40 weeks of gestation (n = 120,854). MAIN OUTCOME MEASURE: Delivery by emergency caesarean section. RESULTS: There was a U-shaped relation between birthweight and the risk of caesarean section, with the lowest risk associated with weights in the range 3,000-3,500 g. Overall, male, were more likely to be delivered by caesarean section (relative risk = 1.2, 95% CI 1.2-1.3). The association between male sex and increased risk of caesarean section persisted after adjusting for birthweight, but only males weighing < 4,000 g were at increased risk of caesarean section compared with similarly sized females. Between 1980 and 1996, there were linear increases in the rate of caesarean section (from 7.1% to 10.7%, r2 = 0.8, P < 0.001) and median birthweight (from 3,360 g in 1980 to 3,420 g in 1996, r2 = 0.8, P < 0.001). The population attributable fraction of caesarean sections related to year of delivery 1981-1996 was not significantly altered by adjusting for birthweight (22.3% vs 21.6%). CONCLUSIONS: There is no evidence to suggest that increasing birthweights have contributed to increasing rates of caesarean section in Scotland between 1980 and 1996 among singleton first births non-electively delivered at 40 weeks of gestation.
Authors: Rafael B Galvão; Renato T Souza; Matias C Vieira; Dharmintra Pasupathy; Jussara Mayrink; Francisco E Feitosa; Edilberto A Rocha Filho; Débora F Leite; Janete Vettorazzi; Iracema M Calderon; Maria H Sousa; Jose G Cecatti Journal: BMC Pregnancy Childbirth Date: 2022-08-04 Impact factor: 3.105