Table 2.

Descriptive statistics for the Natality samples

	Percent or Mean (Standard Deviation)
	Non-isolated clefts (N= 422)	Isolated clefts (N=1,700)	No clefts (N=297,415)
Variable
Prenatal care
Number of prenatal care visits (mean)	10.61 (4.61)	11.56 (4.09)	11.43 (4.02)
Kessner index for prenatal care adequacy (%)
Adequate prenatal care (reference category)	67.22	73.67	75.36
Intermediate prenatal care	23.35	20.82	19.09
Inadequate prenatal care	9.43	5.51	5.55
No prenatal care	0	0	0.003
Infant characteristics
Birth weight in grams (mean)	2683.65 (829.93)	3202.30 (619.00)	3258.89 (616.25)
Gestational age in weeks (mean)	37.18 (3.53)	38.52 (2.58)	38.52 (2.58)
Infant’s sex (%)
Male (reference category)	48.58	57.36	52.05
Female	51.42	42.64	47.95
Maternal characteristics
Marital status (%)
Unmarried (reference category)	36.32	36.59	35.69
Married	63.68	63.41	64.31
Maternal health during pregnancy (%)
No acute illnesses (reference category)	84.67	91.09	92.73
Acute illnesses	15.33	8.91	7.27
No chronic illnesses (reference)	88.44	88.15	90.27
Chronic illnesses	11.56	11.85	9.73
Pregnancy history (mean)
Number of live births	1.21 (1.39)	1.09 (1.19)	1.05 (1.21)
Number of spontaneous stillbirths	0.47 (0.97)	0.42 (0.87)	0.38 (0.82)
Maternal age (%)
Age 26–34 years (reference category)	41.27	41.24	44.78
Age < 20 years	9.91	10.67	10.45
Age 20–25 years	30.66	36.30	30.94
Age > 34 years	18.16	11.79	13.83
Maternal race (%)
Other race (reference category)	5.9	6.69	5.98
Black race	9.67	7.62	16.12
White race	84.43	85.69	77.90
Maternal behavior during pregnancy (%)
No smoking (reference category)	85.85	82.82	89.71
Smoking during pregnancy	14.15	17.18	10.29
Maternal education (%)
Incomplete secondary school (reference category)	23.83	23.11	20.79
Complete secondary school	30.66	34.84	30.13
Incomplete university	21.93	20.76	21.51
Complete university	23.58	21.29	27.57