Participants’ characteristics
Of the total sample size ( n=3,666) of the adolescents, and given that 99.4% response was recorded among all women 15 to 49 years old, non-participation was assumed to be in this range because there were almost no losses of significant records based on completeness. Details of participation rates for the 2013/14 ZDHS are published in the report [17]. Distribution was as follows: comparable rural versus urban distribution (49.8 % vs. 50.2% respectively; p<0.001); 56% had attained at least junior secondary level education, with only 1.9% of the adolescents who had never been to school.
The overall median number of schooling was 8 years (IQR= 6-10) and significant rural vs. urban differences were observed (7 years [IQR= 6-8] vs. 9 years [IQR= 7-10] respectively (P<0.001). Regarding wealth status, 52% of the adolescents were in the poorer, poor and medium wealth quintiles while the other 48% were in the rich and richer quintiles. About 70% of the adolescents who had sex after their first marriage had already given birth at least once.
Table 1: Characteristics of adolescents aged 15 to 19 in Zambia1, 2
|
|
No.
|
% out of n
|
% at least 1 birth3
|
Socio-Demographics
|
Age
|
15
16
17
18
19
|
731
756
667
771
741
|
19.9
20.6
18.1
21.0
20.2
|
3.1
7.7
17.1
35.7
51.1
|
Age at first sex
|
10 to 14
15
16 to 19
Not Had
After Marriage
|
425
458
777
1,797
209
|
11.6
12.5
21.2
49.0
5.7
|
42.2
45.3
40.4
00.0
70.9
|
Type of residence
|
Rural
Urban
|
1,827
1,839
|
49.8
50.2
|
28.7
17.7
|
Educational Attainment
|
None
Primary
Secondary
Tertiary
|
68
1,414
2,170
14
|
1.9
38.6
59.2
0.4
|
46.4
28.7
18.9
14.2
|
Educational Attainment4
|
No Education
Lower Primary
Upper Primary
Junior Secondary
Senior Secondary
Tertiary
|
75
259
1,294
1,347
682
9
|
2.1
7.1
35.3
36.7
18.6
0.3
|
45.3
33.6
26.7
22.7
10.9
11.1
|
Wealth Quintiles
|
1st
2nd
3rd
4th
5th
|
538
598
770
825
935
|
14.7
16.3
21.0
22.5
25.5
|
37.4
30.3
27.5
21.6
8.3
|
Wealth (Rich vs Poor)
|
Rich (4th & 5th)
Poor (1st,2nd & 3rd)
|
1,760
1,906
|
48.0
52.0
|
14.5
31.1
|
Underlying Determinants
|
Religion
|
Catholic
Protestant
Muslim
Other
|
692
2,954
9
11
|
18.9
80.6
0.3
0.3
|
18.6
24.2
0.0
36.5
|
Knowledge of Contraception
|
Does not know
Knows
|
162
3,504
|
4.4
95.6
|
3.7
24.1
|
Abstinence
|
No
Yes
|
3,308
358
|
90.2
9.8
|
14.8
1
|
Proximate Determinants
|
Contraception Use
|
None
At least a method
|
3,278
388
|
89.4
10.6
|
16.4
80.0
|
Marital Status
|
Single
Married
|
3,098
568
|
84.5
15.5
|
13.8
73.9
|
Marital Status
|
Never in union
Married
Living with Partner
Widowed
Divorced
Separated
|
3,042
553
15
5
30
21
|
83.0
15.1
0.4
0.1
0.8
0.5
|
12.8
73.8
80.0
40.0
80.0
71.4
|
Sexual Activity
|
Never had sex
Ever had Sex
|
1,797
1,869
|
49.0
51.0
|
0.0
52.2
|
Abortion
|
No
Yes
|
3,606
60
|
98.4
1.6
|
22.9
41.7
|
1 n=3,666
2Births (ever given birth in the last five years) 849 (23.1%)
3The proportion of adolescents in that group with at least one birth in the last five years
4Adjusted number of years in school. Median years in school - 8 years (IQR = 6-9), Rural- 7 years (IQR= 6-8) Urban- 9 years (IQR= 7-10)
Fertility Determinants
The determinants of adolescent fertility included marriage, knowledge of contraception, contraception use and abortion. About 23.1 % of the adolescents had given birth in the last five years, and the number of births increased with increase in age. A majority of the adolescents (over 90 %) were reported to know of contraception by mentioning at least one contraception method, while contraception use was reported at a low 10%. Over 80% of adolescents were unmarried, while 51% had had sex before. Sixty cases of adolescent girls had terminated a pregnancy (abortion), representing 1.6% of the girls included in this analysis. Abstinence was also low (9.8%) among the adolescents, despite almost half of them reporting that they had never had sex, and 30% reporting that they had not been sexually active. Further investigation revealed that abstinence was captured as post-partum abstinence. Table 1 shows the descriptive statistics of the study population.
In the univariate variable selection procedure, age, age at first sex, residence, educational attainment, wealth status, marital status, abortion (termination of pregnancy), contraceptive use and knowledge of contraception all had a statistically significant association with adolescent births outcome. Table 2a shows the adjusted odds ratios and 95% CIs in the final model.
Table 2a: Determinants for ‘ever giving birth’ among adolescents 15 to 191
|
|
|
% out of n (number)
|
Adjusted OR
(95% CI)
|
P-Value
|
Age
15
16
17
18
19
Per year increase
|
|
19.9 (731)
20.6 (756)
18.1 (667)
21.0 (771)
20.2 (741)
|
1
2.3 (1.3, 4.2)
6.4 (3.6, 11.5)
15.6 (8.9, 27.1)
29.1 (16.9, 50.1)
2.3 (2.1, 2.5)
|
0.007
<0.001
<0.001
<0.001
<0.001
|
Wealth (Rich vs Poor)
Rich (4th &5th)
Poor (1st,2nd & 3rd)
|
|
48.0 (1,760)
52.0 (1,906)
|
1
1.7 (1.3, 2.4)
|
<0.001
|
Educational Attainment
No Education
Lower Primary
Upper Primary
Junior Secondary
Senior Secondary
Tertiary
|
|
2.1 (75)
7.1 (259)
35.3 (1,294)
36.7 (1,347)
18.6 (682)
0.3 (9)
|
1
0.5 (0.2, 1.2)
0.6 (0.3, 1.3)
0.4 (0.2, 0.7)
0.1 (0.0, 0.2)
0.1 (0.0, 0.8)
|
0.123
0.228
0.006
<0.001
0.035
|
Knowledge of Contraception
Does not know
Knows
|
|
4.4 (162)
95.6 (3,504)
|
1
5.4 (1.9, 15.6)
|
0.002
|
Marital Status
Single
Married
|
|
84.5 (3,098)
15.5 (568)
|
1
6.7 (4.9, 9.2)
|
<0.001
|
Contraception Use
None
At least one method
|
|
89.4 (3,278)
10.6 (388)
|
1
14.4 (9.2, 22.4)
|
<0.001
|
Abortion
No
Yes
|
|
98.4 (3,606)
1.6 (60)
|
1
0.5 (0.2, 1.3)
|
0.174
|
1 n=3,666
Having attained junior secondary education was associated with reduced odds of having given birth, compared to those who had no education (aOR 0.4, 95%CI 0.2, 0.7, p=0.006). Following adjustment for age and educational attainment, the poor adolescents were 1.7 times more likely to have given birth, compared to the rich adolescents (95%CI 1.3, 2.4, p<0.001). The odds of having given birth increased with age (aOR 2.3, 95%CI 2.1, 2.5, p<0.001).
Adjusting for age, wealth and educational attainment, the odds of having given birth for adolescents were significantly higher among the adolescents who knew at least one contraceptive method, compared to those that did not know any method (aOR 5.4, 95%CI 1.9, 15.6, p=0.002). Married adolescents were more likely to have given birth, compared to those who were not married, adjusting for socio-demographic variables (aOR 6.7, 95%CI 4.9, 9.2, p<0.001) and this relationship was statistically significant. There was also a strong relationship between contraceptive use and giving birth (aOR 6.7, 95%CI 9.2, 22.4, p<0.001) compared to those who did not use any contraceptive method, adjusting for socio-demographic variables. Abortion (ever terminated a pregnancy) was the only proximate determinant associated with reduced odds of giving birth (aOR 0.4, 95%CI 0.2, 1.3, p<0.174), adjusting for socio-demographic variables. However, this relationship was not statistically significant.
Table 2b: Determinants for ‘ever giving birth’ among adolescents stratified by residence1
|
|
Rural
|
Urban
|
Characteristic Description
|
No.
|
% out of n
|
Adjusted OR
(95%CI)
|
p-value
|
Adjusted OR
(95%CI)
|
p-value
|
Age
15
16
17
18
19
|
731
756
667
771
741
|
19.9
20.6
18.1
21.0
20.2
|
2.5 (2.2, 2.9)2
|
<0.001
|
2.1 (1.8, 2.4)
|
<0.001
|
Wealth (Rich vs Poor)
Rich (4th &5th)
Poor (1st,2nd & 3rd)
|
1,760
1,906
|
48.0
52.0
|
1
1.3 (0.8, 2.0)
|
0.230
|
1
2.4 (1.5, 3.7)
|
<0.001
|
Educational Attainment
No Education
Lower Primary
Upper Primary
Junior Secondary
Senior Secondary
Tertiary
|
75
259
1,294
1,347
682
9
|
2.1
7.1
35.3
36.7
18.6
0.3
|
0.7 (0.6, 0.8)
|
<0.001
|
0.5 (0.3, 0.6)
|
<0.001
|
Knowledge of Contraception
Does not know
Knows
|
162
3,504
|
4.4
95.6
|
1
4.6 (1.4, 15.2)
|
0.014
|
1
1
|
*
|
Marital Status
Single
Married
|
3,098
568
|
84.5
15.5
|
1
8.0 (5.4, 11.9)
|
<0.001
|
1
5.5 (3.2, 9.4)
|
<0.001
|
Contraception Use
None
At least one method
|
3,278
388
|
89.4
10.6
|
1
13.8 (7.4 19.9)
|
<0.001
|
1
15.8 (8.3, 16.0)
|
<0.001
|
Abortion
No
Yes
|
3,606
60
|
98.4
1.6
|
1
0.3 (0.1, 0.8)
|
0.020
|
1
0.6 (0.2, 9.2)
|
0.717
|
1 n=3,666
We also present adolescent fertility determinants by rural and urban residence. Table 2b presents findings from this analysis. The odds of giving birth increased with age for both rural and urban adolescents; though these odds were higher for rural adolescents (aOR 2.5, 95%CI 2.2, 2.9, p<0.001), in comparison to urban adolescents (aOR 2.1, 95%CI 1.7, 2.4, p<0.001). Also, increase in educational attainment was associated with reduced odds of giving birth, and these odds were lower for urban adolescents (aOR 0.7, 95%CI 0.6, 0.8, p<0.001) compared to rural adolescents (aOR 0.5, 95%CI 0.3, 0.6, p<0.001). Interestingly, following adjustment for age and educational attainment, poor urban adolescents had higher odds of giving birth, compared to the rich urban adolescents (aOR 2.4, 95%CI 1.5, 3.7, p<0.001).
Adjusting for age, wealth and educational attainment, the odds of giving birth for rural adolescents were significantly higher among the adolescents who knew at least one contraceptive method, compared to those that did not know any method (aOR 4.6, 95%CI 1.4, 15.2, p=0.014). Interestingly, there were no urban adolescents who and given birth and did not know at least one contraceptive method. While married adolescents were more likely to give birth, compared to the unmarried, adjusting for socio-demographic variables, the odds of giving birth were much higher among rural married adolescents (aOR 8.0, 95%CI 8.0, 5.4, 11.9 p<0.001) compared to urban married adolescents (aOR 5.5, 95%CI 8.3, 16.0, p<0.001), and these relationship were both statistically significant.
In addition, and adjusting for socio-demographic variables, the odds of giving birth and using at least one contraceptive method were significantly higher among urban adolescents (aOR 15.8, 95%CI 8.3, 16.0, p<0.001) compared to rural adolescents (aOR 13.8, 95%CI 7.4, 19.9, p<0.001). Finally, abortion (ever terminated a pregnancy) among rural adolescents was significantly associated with reduced odds of giving birth (aOR 0.3, 95%CI 0.1, 0.8, p<0.020), adjusting for socio-demographic variables.