Prenatal factors related to face presentation: a case-control study.

PURPOSE: Face presentation is rare. Its risk factors are debated and its mechanism is practically unknown. The objectives of the study were to determine the prenatal factors associated with face presentation at delivery and discuss the mechanism by which it occurs.

METHODS

Retrospective case-control study including all cases of face presentation of infants born at a gestational age between 22 and 42 weeks of gestation over a 16 year period. For each case, we selected three control women who gave birth the same day.

RESULTS

During the study period, there were 64 cases of face presentation (incidence: 0.8 per 1000 births), which we compared with 191 controls. After logistic regression, the four factors most closely associated with delivery in face presentation were twin pregnancy [OR 25.8 (4.7-141.8)], birth weight <2500 g [OR 8.9 (2.1-38.0)], polyhydramnios [OR 7.1 (2.0-25.2)], and multiparity [OR 3.6 (1.5-8.6)].

CONCLUSION

These factors are all associated with a reduction in the uterine constraints on fetal attitude. This may play a role in the mechanism resulting in face presentation.