Table 1.

Robson 10-Group Classification System

Robson Category	Description
1	Nulliparous women with a single cephalic pregnancy, ≥37 weeks’ gestation, in spontaneous labor
2	Nulliparous women with a single cephalic pregnancy, ≥37 weeks’ gestation, who either had labor induced or gave birth by cesarean before labor
2a	Nulliparous women with a single cephalic pregnancy, ≥37 weeks’ gestation, who had labor induced
2b	Nulliparous women with a single cephalic pregnancy, ≥37 weeks’ gestation, who gave birth by cesarean before labor
3	Multiparous women without a previous uterine scar, with a single cephalic pregnancy, ≥37 weeks’ gestation, in spontaneous labor
4	Multiparous women without a previous uterine scar, with a single cephalic pregnancy, ≥37 weeks’ gestation, who either had labor induced or gave birth by cesarean before labor
4a	Multiparous women without a previous uterine scar, with a single cephalic pregnancy, ≥37 weeks’ gestation, who had labor induced
4b	Multiparous women without a previous uterine scar, with a single cephalic pregnancy, ≥37 weeks’ gestation, who gave birth by cesarean before labor
5	All multiparous women with at least one previous uterine scar, with a single cephalic pregnancy, ≥37 weeks’ gestation
6	All nulliparous women with a single breech pregnancy
7	All multiparous women with a single breech pregnancy, including women with previous uterine scars
8	All women with multiple pregnancies, including women with previous uterine scars
9	All women with a single pregnancy with a transverse or oblique lie, including women with previous uterine scars
10	All women with a single cephalic pregnancy, <37 weeks’ gestation, including women with previous uterine scars

Source: Robson 2001.²⁴