Is abnormal labor associated with shoulder dystocia in nulliparous women?
OBJECTIVE
This study was undertaken to examine the relationship between labor abnormalities and shoulder dystocia in nulliparous women.


METHODS
Nulliparous women whose delivery was complicated by shoulder dystocia were studied and compared with a control group selected based on the best possible match for race, labor type (spontaneous or induced), and birth weight. The duration of first and second stage of labor, as well as the rates of labor progress, were calculated and compared between groups.


RESULTS
During this 4-year study period, there were 8010 nulliparous singleton deliveries of which 65 (0.8%) were complicated by shoulder dystocia. Compared with controls, there was no difference in the rate of cervical dilation in the active phase of the first stage of labor. In the shoulder dystocia group, more patients had a second stage of labor greater than 2 hours (22% vs 3%; P <.05) and had operative vaginal deliveries (26% vs 1.5%; P <.001). In shoulder dystocia cases with birth weight greater than 4000 g, 33% had a second stage of labor greater than 2 hours.


CONCLUSIONS
In our population, the combination of fetal macrosomia, second stage of labor longer than 2 hours and the use of operative vaginal delivery were associated with shoulder dystocia in nulliparous women.
Mehta
Shobha H
SH
Division of Maternal Fetal Medicine, Department of Obstetrics and Gynecology, Hutzel Hospital, Wayne State University, Detroit, MI 48201, USA. smehta@med.wayne.edu
Bujold
Emmanuel
E
Blackwell
Sean C
SC
Sorokin
Yoram
Y
Sokol
Robert J
RJ
D000328:Adult; D001034:Apgar Score; D001720:Birth Injuries / Q000453:epidemiology* / Q000209:etiology; D001724:Birth Weight; D016022:Case-Control Studies; D004420:Dystocia / Q000453:epidemiology / Q000209:etiology*; D005260:Female; D005500:Follow-Up Studies; D005865:Gestational Age; D006801:Humans; D007231:Infant, Newborn; D007746:Labor Presentation; D007747:Labor Stage, First; D007748:Labor Stage, Second; D010298:Parity; D011247:Pregnancy; D011256:Pregnancy Outcome; D015995:Prevalence; D011336:Probability; D012016:Reference Values; D018570:Risk Assessment; D012782:Shoulder