Uterine contractions preceding labor.
OBJECTIVE
To evaluate whether 12 contractions in 1 hour is a meaningful signal that spontaneous labor has begun or is imminent.


METHODS
This prospective observational cohort study includes all women reporting contractions who presented to a labor and delivery triage unit between August 1 and October 31, 2006, who met the following criteria: 1) 36 0/7 to 41 6/7 weeks of gestation, 2) cervical dilation less than 4 cm, 3) intact membranes, and 4) no other medical or obstetric complications that might influence admission. Each woman received external fetal monitoring for a minimum of 1 hour. Women were discharged home if cervical dilation did not advance and the fetal heart rate pattern was reassuring. Women who progressed to a cervical dilation of 4 cm were admitted with the diagnosis of labor.


RESULTS
Among 768 women studied, labor was diagnosed within 24 hours in 268 (76%) with 12 or more contractions per hour compared with 216 (52%) of 416 women with fewer than 12 contractions per hour, P<.001. Cervical condition and fetal station were more advanced on presentation in women with 12 or more contractions per hour.


CONCLUSIONS
Twelve contractions or more per hour at term is a meaningful signal that true labor has either begun or is imminent.


METHODS
II.
Pates
Jason A
JA
Department of Obstetrics and Gynecology, the University of Texas Southwestern Medical Center at Dallas, Dallas, Texas, USA. japates@aol.com
McIntire
Donald D
DD
Leveno
Kenneth J
KJ
D000293:Adolescent; D000328:Adult; D015331:Cohort Studies; D005260:Female; D005865:Gestational Age; D006801:Humans; D007745:Labor Onset / Q000502:physiology; D007747:Labor Stage, First / Q000502:physiology*; D007743:Labor, Obstetric / Q000502:physiology*; D008423:Maternal Age; D010298:Parity; D011247:Pregnancy; D011446:Prospective Studies; D014590:Uterine Contraction / Q000502:physiology*