Asynclitic birth

In obstetrics, asynclitic birth, or asynclitism, refers to the malposition of the fetal head in the uterus relative to the birth canal. Many babies enter the pelvis in an asynclitic presentation, but in most cases, the issue is corrected during labor. Asynclitic presentation is not the same as shoulder presentation, where the shoulder enters first.

Fetal head asynclitism may affect the progression of labor, increase the need for obstetrical intervention, and be associated with difficult instrumental delivery. The prevalence of asynclitism at transperineal ultrasound was common in nulliparous women (those who have never given birth) at labor stage two and seemed more commonly associated with non occiput anterior position, suggesting an autocorrection typically occurs. When self-correction does not occur, obstetrical intervention is necessary. Persistent asynclitism can cause problems with dystocia, and has often been associated with cesarean births. However, a skilled midwife or obstetrician a complication-free vaginal birth may be achievable through movement and positioning of the mother, and patience and allowing the baby to move through the pelvis and moulding of the skull during the birthing process. Other options include the use of vacuum-assisted delivery and forceps. No evidence suggests that one asynclitic presentation predicts another in subsequent childbirth.