. Author manuscript; available in PMC: 2015 Sep 1.

Published in final edited form as: J Perinat Med. 2014 Sep 1;42(5):549–557. doi: 10.1515/jpm-2014-0073

Table 1.

Descriptive Characteristics of the study group

Characteristic	N=154
	n	% or IQR
African-American	142	92.2
Maternal age (years, median)	24	21-27
Gestational age at examination (weeks median)	21	14-29
Gestational age at birth (weeks median)	39	37-40
Cervical length (mm, median)	37	33-41
Smoking	19	12.3
Nulliparous	32	20.7
Prior preterm delivery	18	11.6

IQR, interquartile range