Obstetric pelvimetry by three-dimensional computed tomography in non-pregnant Japanese women: a retrospective single-center study

Figures & data

Figure 1. Representative 3D CT images. Measurements of the obstetric conjugate (A) and transverse diameter of the pelvic inlet (B).

Figure 2. Histograms of the obstetric conjugate (A) and transverse diameter of the pelvic inlet (B).

Table 1. Reference ranges for OC and TD.

OC		TD
127.0 ± 9.5 (95% CI 126.5–127.5) mm		126.8 ± 7.5 (95% CI 126.4–127.2) mm
Percentile	mm	Percentile	mm
3	109.5	3	113.4
10	115.0	10	117.5
50	126.8	50	126.4
90	139.4	90	136.4
97	145.4	97	141.5

Data were presented as mean ± SD.

CI: confidence interval; OC: obstetric conjugate; SD: standard deviation; TD: transverse diameter of the pelvic inlet.

Table 2. Incidence of contracted pelvis.

OC		TD
127.0 ± 9.5 mm		126.8 ± 7.5 mm
(mm)	n (%)	(mm)	n (%)
<95†	1 (0.08)	<105†	1 (0.08)
95≤, <105‡	9 (0.7)	105≤, <115‡	57 (4.5)
105≤, <125	531 (42.0)	115≤, <130	787 (62.3)
125≤	722 (57.2)	130≤	418 (33.1)

†Contracted pelvis as defined by the Japan Society of Obstetrics and Gynecology in 1972.

‡Relatively contracted pelvis according to the same definition.

Data were presented as mean ± SD.

OC: obstetric conjugate; SD, standard deviation; TD: transverse diameter of the pelvic inlet.

Figure 3. Scatter plots of the obstetric conjugate, transverse diameter of the pelvic inlet, and height.

Table 3. OC and TD in relation to height and age.

	OC (mm) (n = 1,076)			TD (mm) (n = 1,076)
	Coefficient (B)	95% CI	p	Coefficient (B)	95% CI	p
Height (cm)	0.75	0.66, 0.84	<.001	0.62	0.56, 0.69	<.001
Age (cm)	−0.10	−0.18, −0.01	.026	0.14	0.07, 0.20	<.001

Data were presented as mean ± SD.

CI: confidence interval; OC: obstetric conjugate; SD: standard deviation; TD: transverse diameter of the pelvic inlet.