The impact of the nine-item list intervention on the rate of obstetric anal sphincter injury in women with spontaneous and operative vaginal births.

Sir,

We would like to thank Dr Rasmussen for his interest in our article and for raising some important points regarding the rate of obstetric anal sphincter injury (OASI).

The overall purpose of the nine‐item list intervention of organizational and cultural changes was to increase the number of spontaneous vaginal births without increasing adverse neonatal outcomes. In the present paper we evaluated long‐term effects on outcomes in Robson group 1, with the emphasis on neonatal variables.

We agree that vaginal birth is the correct denominator when comparing OASI rates, although all births are widely used. It is crucial when presenting clinical data that all absolute numbers are available, enabling recalculation and construction of new tables suitable for benchmarking.

In this time‐series study, causality has not been proven between the nine‐item list intervention and any outcome reported, including OASI. We observed that the rate of OASI decreased early after introduction of the nine‐item list. One could speculate about reasonable explanations, one of which is a decreased number of operative vaginal births. Another possibility is that the impact of teamwork, team skills training, risk classification of women, and a midwife with corresponding competence might have influenced the rate of OASI.

As suggested by Dr Rasmussen, we hereby present the rate of OASI overall and in spontaneous vaginal births and operative vaginal births according to study period (Table 1). The overall rate of OASI (grade III and IV) in women with vaginal births dropped significantly after introduction of the nine‐item list and remained fairly constant over time. The same pattern was found in the spontaneous vaginal births group. The rate of OASI in the operative vaginal births group did not differ between the time periods. However, absolute numbers indicate the need for a targeted intervention of pelvic floor protection, accurate diagnostic methods, and professional repair.

TABLE 1

The rate of OASI in spontaneous and operative vaginal births according to study period

OASI	Mode of vaginal delivery	2004‐2006 Before the nine‐item list	2007‐2010 During introduction of the nine‐item list	2011‐2014 Early post introduction of the nine‐item list	2015‐2018 Late post introduction of the nine‐item list
OASI grade III and IV, n (%)	SVD + OVD	218 (9.6)	210 (6.2)	222 (6.5)	159 (5.3)	P < .05 Before vs all others
	SVD	132 (7.5)	138 (4.8)	158 (5.3)	122 (4.6)	P < .05 Before vs all others
	OVD	86 (17.3)	72 (15.4)	64 (14.7)	37 (11.2)	NS
OASI grade III, n (%)	SVD + OVD	196 (8.7)	181 (5.4)	203 (5.9)	145 (4.9)	P < .05 Before vs all others
	SVD	119 (6.7)	118 (4.1)	140 (4.7)	111 (4.2)	P < .05 Before vs all others
	OVD	77 (15.5)	63 (13.4)	63 (14.5)	34 (10.3)	NS
OASI grade IV, n (%)	SVD + OVD	22 (1.0)	29 (0.9)	19 (0.6)	14 (0.5)	NS
	SVD	13 (0.7)	20 (0.7)	18 (0.6)	11 (0.4)	NS
	OVD	9 (1.8)	9 (1.9)	1 (0.2)	3 (0.9)	NS

NS, non‐significant; OASI, obstetric anal sphincter injury; OVD, operative vaginal delivery; SVD, spontaneous vaginal delivery.