Demographic Changes and Effects on the Mode of Delivery. A retrospective Analysis of a large Birth Registry containing 27,786 Singleton Deliveries in a Level I Center
IUGA Academy. Huebner M. 06/30/18; 212984; 322
Markus Huebner
Markus Huebner

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Demographic changes and effects on the mode of delivery. A retrospective analysis of a large birth registry containing 27,786 singleton deliveries in a level I center

Huebner, M1; Abele, H2; Reisenauer, C2; Kagan, K2; Hoopmann, M2; Wagner, P2; Schoenfisch, B2; Brucker, S2; Rall, K2

1: Women’s Center Bern, Lindenhofgruppe, Bern, Switzerland; 2: Department of Women?s Health, University Hospital of Tuebingen, Germany

Introduction: Epidemiological analysis of pelvic floor disorders show strong correlations to maternal demographics such as age, body mass index and parity.(1) Whether increasing rates of cesarean section can be justified by suspected demographic changes in our population remains controversial.(2)

Objective: It was the aim of this retrospective study, to analyze a large cohort of deliveries regarding maternal demographics and look for effects over time seeking for statistically and clinically relevant changes. Potentially effects of demographics were analyzed regarding mode of delivery. In addition, mode of delivery in a maternal high risk situation for developing pelvic floor disorder in later life (maternal height <160cm; fetal weight >4kg) was determined.

Methods: All deliveries within an eleven-year period between 2004 and 2014 were analyzed retrospectively. Data were extracted out of the digital birth registry of a Level I perinatal center. Women who delivered multiples were excluded. All statistical analyses were done using R version 3.3.2. including Fisher´s exact test, linear regression analysis and estimation of effect sizes was done for potential changes over the years. The study was approved by the local ethical committee.

Results: N=27,786 singleton deliveries were subject to analysis. Their annual number increased continuously from 2,093 in 2004 up to 2,778 in 2014. Mean age of all mothers at delivery was 31.4 years (median 31, SD 5.3). Within the eleven-year period, the mean age of all patients slightly increased from 31.2 years (median 31, SD 5.2) in 2004 to 31.5 years (median 32, SD 5.0) in 2014 (p<0.001, gradient 0.04, partial eta2=0.0006). Mean body mass index (BMI) before pregnancy was 24.2 (median 23.0, SD 5.4) and increased from 23.7 (median 22.7, SD 4.5) in 2004 to 24.7 (median 23.4, SD 5.2) in 2014. Mean BMI at delivery was 29.1 (median 28.1, SD 5.7) increasing from mean 28.6 (median 27.7, SD 4.7) in 2004 to 29.7 (median 28.7, SD 6.3) in 2014 (p<0.001, gradient 0.11; partial eta2=0.0049). The patients with planned cesarean section were the oldest (mean 32.5, median 33, SD 5.3) followed by those with emergency (mean 31.6, median 32, SD 5.6) and secondary cesarean sections (mean 31.4, median 32, SD 5.3) and compared to those with spontaneous (mean 31.0, median 31, SD 5.1) or instrument-assisted vaginal delivery (vacuum: mean 32, median 31, SD 5.0, and forceps: mean 30.2, median 30, SD 5.4). Regarding the maternal high risk situation for developing pelvic floor disorders in later live (maternal height <160cm and fetal weight >4kg, n=106) the mode of delivery was distributed as follows: spontaneous (40.1%; n=43), vaginal operative (4.7%; n=5), elective C-section (16.9%; n=18), secondary C-section (36.8%; n=39), emergency C-section (1%; n=1), overall rate of C-section (54.7%; n=58)

Conclusions: Age and BMI before pregnancy and before delivery increase significantly, however, given small effect sizes the clinically relevant influence might be low. In a high risk group of women regarding the development of pelvic floor disorders in later life, the rate of C-section was higher than 50%.

Figure 1:

maternal age and maternal BMI

at delivery in different modes of delivery,
boxes thickness represents number of deliveries


  1. Nygaard I, Barber MD, Burgio KL, Kenton K, Meikle S, Schaffer J, et al. Prevalence of symptomatic pelvic floor disorders in US women. JAMA. 2008;300(11):1311-6.
  2. Janssens S, Wallace KL, Chang AM. Prepartum and intrapartum caesarean section rates at Mater Mothers' Hospital Brisbane 1997-2005. Aust N Z J Obstet Gynaecol. 2008;48(6):564-9.


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