. Author manuscript; available in PMC: 2016 Feb 13.

Published in final edited form as: N Engl J Med. 2015 Aug 13;373(7):632–641. doi: 10.1056/NEJMoa1500600

Table 2.

Characteristics of the Patients Enrolled in the Study.^*

Characteristic	Open Group (N = 5532)	Masked Group (N = 5576)
Age — yr	27.4±5.9	27.2±5.8
Week of pregnancy at randomization	39.4±1.2	39.4±1.2
Race — no. (%)^†
Black	1326 (24.0)	1350 (24.2)
White	3297 (59.6)	3281 (58.8)
Other	909 (16.4)	945 (16.9)
Body-mass index before pregnancy^‡	27.4±7.2	27.4±7.0
Educational level — yr	12.8±2.6	12.8±2.7
Cervical dilation at randomization — cm
Median	5	5
Interquartile range	4–6	4–6
Type of labor — no. (%)
Spontaneous	2259 (40.8)	2311 (41.4)
Induced	3273 (59.2)	3265 (58.6)
Nulliparous — no. (%)	2354 (42.6)	2373 (42.6)

Plus–minus values are means ±SD. There were no significant differences in baseline characteristics between the two groups.

^†

Race was self-reported.

^‡

The body-mass index is the weight in kilograms divided by the square of the height in meters.