In terms of intrapartum ขณะคลอด risk factors ปัจจัยเสี่ยง, observational studies have suggested that SGH is often (but not always), preceded by a difficult vacuum extraction with either incorrect positioning of the cup, prolonged extraction time more than three pulls or greater than two cup detachments or failed vacuum extraction These observations are not all confirmed in the case control analysis in the study of Boo et al This study showed significant risk factors for SGH were nulliparity