OBJECTIVE: To explain the increasing rates of vacuum extraction in Sweden. DESIGN: Population-based register study. SETTING: Nationwide study in Sweden. POPULATION: A total of 589 108 primiparous women with singleton, term live births in 1992-2010. METHODS: Odds ratios with 95% confidence intervals were estimated for potential risk factors for vacuum extraction and emergency cesarean. To explain the increase in vacuum extraction over time, we successively adjusted for maternal and infant characteristics in four different models. MAIN OUTCOME MEASURES: Vacuum extraction. RESULTS: Rates of vacuum extraction increased from 11.5% in 1992 to 14.8% in 2010. The risk of vacuum extraction increased with maternal age and gestational length, but decreased with increasing maternal height. The increased use of vacuum extraction over time was partly explained by increasing maternal age and increased use of epidural anesthesia. Among women with and without epidural analgesia, the increase in vacuum extraction over time was confined to vacuum extraction due to signs of fetal distress. CONCLUSIONS: Depending on risk factors, the odds of being delivered by vacuum extraction can vary immensely from one woman to another. Increasing maternal age explains a substantial fraction of the increase in vacuum extraction use since 1992. Whether the increase in vacuum extractions due to fetal distress reflects a true increase in fetal distress during labor remains to be explained.
OBJECTIVE: To explain the increasing rates of vacuum extraction in Sweden. DESIGN: Population-based register study. SETTING: Nationwide study in Sweden. POPULATION: A total of 589 108 primiparous women with singleton, term live births in 1992-2010. METHODS: Odds ratios with 95% confidence intervals were estimated for potential risk factors for vacuum extraction and emergency cesarean. To explain the increase in vacuum extraction over time, we successively adjusted for maternal and infant characteristics in four different models. MAIN OUTCOME MEASURES: Vacuum extraction. RESULTS: Rates of vacuum extraction increased from 11.5% in 1992 to 14.8% in 2010. The risk of vacuum extraction increased with maternal age and gestational length, but decreased with increasing maternal height. The increased use of vacuum extraction over time was partly explained by increasing maternal age and increased use of epidural anesthesia. Among women with and without epidural analgesia, the increase in vacuum extraction over time was confined to vacuum extraction due to signs of fetal distress. CONCLUSIONS: Depending on risk factors, the odds of being delivered by vacuum extraction can vary immensely from one woman to another. Increasing maternal age explains a substantial fraction of the increase in vacuum extraction use since 1992. Whether the increase in vacuum extractions due to fetal distress reflects a true increase in fetal distress during labor remains to be explained.