24 Chapter 2 Methods Data collection For this nationwide study, we used consolidated data of the years 2010 to 2013 from Perined, the national perinatal register that includes data from almost all births in the Netherlands. Perined aims to improve the quality of perinatal care through providing data for research and audits on adverse outcomes. The Perined register includes data from: primary midwife-led care (the national perinatal database 1); secondary obstetrician-led care (the national perinatal database 2); paediatric care (the national neonatal register); and primary midwifery care by general practitioners (the national perinatal database h). The data are routinely recorded by the care providers and combined into the Perined register via a validated linkage method (37, 38). More than 98% of all midwifery practices and obstetric hospital units record their births in this combined database (39). All single childbirths from 37 weeks’ gestation onwards were included. Exclusion criteria were missing data on: postal code; parity; or from the national perinatal database 1, covering midwife-led care, but where the woman was referred to obstetrician-led care, covered by the national database 2. In the Netherlands, low-risk women in primary midwife-led care are cared for by independent midwives who attend home births, low-risk hospital births, and births in alongside and free-standing birth centres. The Dutch Birth Centre Study showed that health outcomes, experiences, and costs for lowrisk women are similar for planned birth in a birth centre and planned birth in a hospital, both supervised by a primary care midwife (40, 41). When risks for adverse outcomes increase or complications arise, women are referred to obstetrician-led care. Interventions in childbirth such as induction and augmentation of labour, pain medication, instrumental birth, and CS, are only available in an obstetrician-led care setting (42, 43). Intrapartum interventions may be used for women in midwife-led care at the onset of labour after referral to obstetrician-led care. Therefore, intervention rates are not comparable for women who are in midwife-led care and women who are in obstetrician-led care at the onset of labour. The VU University Medical Center confirmed that ethical approval was not required for this study according to the Dutch legislation (reference WC2016055; http://www.ccmo.nl/en/your-research-does-it-fall-under-the-wmo). Interventions Births were attributed to one of the twelve Dutch administrative provinces (further referred to as ‘regions’) according to the residential postal code of the mother. All low-risk women have access to all types of birth settings, but not all types are present in all regions (44). We adjusted for this by using the residential postal code of the mother.
RkJQdWJsaXNoZXIy MTk4NDMw