Table 4.

Results of adjusted logistic regression analysis of the association between sexual behaviours and adolescent pregnancy, 1988–2019.

Survey years	1988–1998	2003–2008	2011–2019	Overall sample (1988–2019)
Population analysed (unweighted)	2541	3350	8665	14 556
Number currently pregnant (unweighted)	96	117	282	495
	Adjusted odds ratio (95% CI)	Adjusted odds ratio (95% CI)	Adjusted odds ratio (95% CI)	Adjusted odds ratio (95% CI)
Age at first sex	P=0.63	P=0.79	P=0.10	P=0.14
≤14 years	0.85 (0.45 to 1.63)	0.91 (0.44 to 1.88)	0.63 (0.36 to 1.10)	0.75 (0.52 to 1.10)
≥15 years	1.00	1.00	1.00	1.00
Number of previous sex partners		P=0.03*	P=0.79	P=0.04*
1	–	0.29 (0.10 to 0.88)	0.73 (0.27 to 1.95)	0.46 (0.23 to 0.95)
2	–	0.56 (0.21 to 1.52)	0.90 (0.31 to 2.58)	0.67 (0.33 to 1.36)
Three or more	–	1.00	1.00	1.00
Age of last sexual partner		P=0.02	P=0.20	P=0.39
Below 20 years	–	1.00	1.00	1.00
More than 20 years	–	0.14 (0.03 to 0.76)	2.00 (0.69 to 5.81)	1.46 (0.61 to 3.48)
Knowledge of contraception	P=0.20	P=0.08		P=0.02
Knows no method	0.62 (0.30 to 1.29)	0.36 (0.11 to 1.15)	–	0.49 (0.27 to 0.90)
Knows modern or traditional method	1.00	1.00	–	1.00
knowledge of fertility period during menstruation	P=0.56	P=0.45	P=0.02	P=0.83
Just before or during menstrual period	2.09 (0.50 to 8.67)	1.88 (0.70 to 5.05)	0.17 (0.04 to 0.69)	0.90 (0.45 to 1.77)
Right after menstrual period or at any time	0.95 (0.42 to 2.13)	1.24 (0.60 to 2.56)	0.51 (0.24 to 1.07)	0.87 (0.56 to 1.36)
Halfway between two menstrual periods	1.00	1.00	1.00	1.00

*Test for linear trend