Table 2: Items Selected as Covariates

	Premature Delivery	Premature Rupture of Membranes	Weak Labor Pains	Prolonged Labor	Atonic Bleeding
Item	Obstetric history	BMI	BMI	BMI	Obstetric history
	Smoking during pregnancy	Obstetric history	Obstetric history	Obstetric history	Smoking during pregnancy
	Ovarian cystoma	Smoking during pregnancy	Smoking during pregnancy	Smoking during pregnancy	Ovarian cystoma
	Infectious diseases	Malformation of uterus	Ovarian cystoma	Infectious diseases	Infectious diseases
	Periodontal disease	Infectious diseases	Infectious diseases	Use of a tocolytic	Use of a tocolytic
	Threatened premature delivery	Threatened premature delivery	Hiesho care during labor	Hiesho care during labor	Fatigue in the process of delivery
	Use of a tocolytic	Use of a tocolytic	Stress during the latter half of pregnancy	Stress during the latter half of pregnancy	Hiesho care during labor
	Fetal malformation	Congenital fetal anomalies	Anxiety during the latter half of pregnancy	Anxiety during the latter half of pregnancy	Stress during the latter half of pregnancy
	Congenital fetal anomalies	Premature delivery	Gestational age at delivery	Gestational age at delivery	Use of an ecbolic
	Stress during the latter half of pregnancy		Use of an ecbolic	Use of an ecbolic	Perineal laceration
	Premature rupture of membranes		Premature rupture of membranes	Premature rupture of membranes	Use of an oxytocic
			Prolonged labor	Weak labor pains	Weak labor pains
			Anomaly of the rotation	Anomaly of the rotation	Prolonged labor
			Giant baby	Giant baby	Giant baby
			Suspension of delivery	Suspension of delivery
			Cephalopelvic disproportion	Cephalopelvic disproportion