Novel, Group-Based Trajectories of Labor Progress in Nulliparous Women With Low-Risk Pregnancies.

OBJECTIVE

To characterize labor progress among nulliparous women by applying group-based trajectory analysis and examining predictors of group membership.

DESIGN

Retrospective observational.

SETTING

An existing biobank and database from a birth hospital in Western Pennsylvania.

PARTICIPANTS

Nulliparous women with low-risk pregnancies at term gestation with singleton fetuses in vertex presentation (N = 401).

METHODS

We characterized labor progress by applying group-based trajectory analysis. We conducted a multinomial logistic regression analysis to examine the relationships among labor trajectory groups and various demographic and clinical variables.

RESULTS

We identified three trajectories of labor in the group-based trajectory analyses: precipitously progressing (n = 76, 20.1%), average (n = 245, 59.1%), and slow progress (n = 80, 20.7%). Only gestational age at birth significantly predicted trajectory group membership, and an increased gestational age was associated with greater odds of belonging to the slower progress group (OR = 1.43, 95% CI [1.06, 1.92]).

CONCLUSION

We identified multiple trajectories of labor progress in a sample of nulliparous women with low-risk pregnancies at term gestation. Gestational age may help predict the trajectory of labor.