Table 1.

Description of the study groups and clinical variables

		Overall (n = 6884)		Group A (n = 3526)		Group B (n = 3358)		p value
		Mean (n)	SD (%)	Mean (n	SD (%)	Mean (n	SD (%)
Maternal characteristics	Maternal age (years)	33.3	5.5	33.2	5.5	33.5	5.4	0.069
	BMI	23.9	4.9	23.8	4.7	24.1	5.1	0.018
	Gestational Age (weeks)	39	1.89	38.98	1.93	39.03	1.85	0.282
	Parity (primiparous)	4352	63.2	2238	63.5	2114	63.0	0.656
Maternal clinical characteristics	Diabetes	1194	17.34	600	17.02	594	17.69	0.461
	Ipertensive disorders	491	7.13	260	7.37	231	6.88	0.425
	Thyroid disorders	856	12.43	418	11.85	438	13.04	0.135
	Previous uterine surgery	1301	18.90	512	14.52	789	23.50	0.001
	Other maternal complications*	367	5.33	235	6.66	132	3.93	0.001
Pregnancy complications	Macrosomia	187	2.72	131	3.72	56	1.67	0.001
	IUGR	424	6.16	198	5.62	226	6.73	0.054
	Maformation	180	2.61	104	2.95	76	2.26	0.074
	Olygohydramnios	379	5.51	207	5.87	172	5.12	0.173
	Polyhydramnios	504	7.37	308	8.74	196	5.84	0.001
	Placental abnormalities #	117	1.70	61	1.73	56	1.67	0.841
Intrapartum variables	Onset of labour
	Spontaneous	2928	42.53	1561	44.27	1367	40.71	0.003
	Induction of labour	2711	39.38	1332	37.78	1379	41.07	0.005
	No labour	1245	18.09	633	17.95	612	18.23	0.769
	Epidural analgesia	2068	36.7	1025	35.4	1043	38.0	0.046
	Mode of birth Vaginal	4644	82.4	2384	82.4	2260	82.3	0.784
	Caesarean	1967	28.57	1011	28.67	956	28.47	0.852
	Vacuum assisted	273	3.97	131	3.72	142	4.23	0.275

BMI body mass index, IUGR intra uterine growth restriction, SD standard deviation

*Other maternal complications = heart diseases, lung disease, Kidney disease, autoimmune disease, metabolic disease, coagulopathy

^#Placental abnormalities = Placenta praevia, accreta, percreta, increta