Effect of Maternal Body Mass Index on Labor Progress in Nulliparous Women

For nulliparous cases presenting to the labor ward, maternal height & weight will be collected at the time of admission to calculate the BMI (body mass index) & further classified according to WHO (World Health Organization) categories. Putting into consideration the physiological increase in BMI related to pregnancy, the overweight participants whose BMI (25-29.9) will be combined with the normal range BMI (18.5-24.9) category. Labor characteristics of these participants will be then compared with those of the underweight (BMI less than 18.5) & obese (BMI 30 or higher) participants.Females are assigned in one of 3 groups based on their BMI; Underweight group (BMI <18.5kg/m2), Control group whose BMI within normal range (18.5-29.9 kg/m2),& Obese group (BMI more than or equal 30kg/m2).

Labor management protocols are fixed. Data on labor progression are collected, including cervical dilatation, cervical effacement, head station & descent. The median duration of labor , estimated by rate of cervical dilatation in cm, will be used as a measurement of labor progression in each group.

A cesarean section for abnormal labor pattern will be documented as failure of progress.

Inclusion criteria

• nulliparous women in active phase of labor, with an age range from 20 to 40 years.

Full term pregnancy, singleton, viable fetus, cephalic (vertex) presentation, occipito-anterior position.

Exclusion criteria

• Multiparous women. Preterm labor. Passed date delivery. Multiple gestation. Large fetal weight (more than 4000g). Intrauterine fetal death. Intrauterine fetal growth restriction. Major fetal congenital anomalies. Rupture of membranes before onset of active labor. Fetal malposition or malpresentation. Inadequate pelvis or cephalopelvic disproportion. Maternal medical disorder.

Induction of labor by oxytocin or prostaglandins. Conditions requiring urgent delivery eg antepartum haemorrhage, fetal distress, cord prolapse.