Table 3. Distribution of missing values in the KCMC medical birth registry, 2000–2015 (N = 50,847).

Variables with missing data	Frequency	Percent Missing
Body Mass Index (BMI)	15,911	31.3
HIV status	12,057	23.7
Gestational age at birth categories	4,017	7.9
Referral status	1,880	3.7
Antenatal Care visits	936	1.8
Alcohol use during pregnancy	636	1.3
Occupation	308	0.6
Sex of the child	227	0.5
Marital Status	186	0.4
Mode of delivery	142	0.3
Birth weight of the child	133	0.3
Perinatal status (primary outcome)	123	0.2
Area of residence	120	0.2
Education level	100	0.2
Age categories	85	0.2