Intervention of the obstetrician during childbirth in a supposedly low-risk population and influence of parity.

Objective: Compare obstetrician intervention and calling rates during labour and delivery between low-risk and high-risk women and study the influence of parity on these rates.

Material And Methods: Descriptive retrospective study conducted on 227 patients in a university maternity unit (level 3 university hospital maternity unit) between 1st and 30th January 2014. The low- and high-risk populations were characterised according to the French National Authority for Health (HAS) and NICE guidelines. The obstetrician intervention criteria were: Caesarean section, instrumental vaginal delivery, artificial delivery/uterus examination and postpartum haemorrhage. The obstetrical team also had to call the obstetrician in case of foetal heart rate abnormalities, scalp blood pH measurement, third and/or fourth degree perineal tears, labour dystocia, or any other severe event occurring during labour or delivery.

Results: In univariate analysis, the obstetrician intervention rates were respectively 44.5% and 34.4% in the high- and low-risk groups (P=0.13). The obstetrician calling rates were similar between the two groups. Using logistic regression model including parity, the obstetrician intervention rate became significantly higher in the "high-risk" group (OR 2.044, 95% CI 1.129-3.703, P=0.018). In the low-risk population, the intervention rate was significantly increased for nulliparous women compared with multiparas (47.5% versus 9.7%, P<0.001, OR=8.2, CI 95% 2.2 to 46.9).

Conclusion: One third of the women defined as low-risk patients appear to need an obstetrician intervention during labour and delivery, with a major influence of parity.