Table 3 Factors associated with time to second birth interval among women in DR Congo and Ethiopia

Fertility desired

No more (R)

1

1

1

1

1

1

Wanted

0.93(0.89,0.96)^c

0.93(0.89,0.96)^c

0.93(0.89,0.97)^c

0.64(0.62,0.67)^c

0.64(0.61,0.67)^c

0.64(0.61,0.67)^c

Undecided

0.92(0.84,1.00)

0.92(0.84,1.00)^a

0.92(0.84,1.00)

0.87(0.78,0.96)^b

0.84(0.76,0.93)^c

0.80(0.72,0.89)^c

Contraceptive use

Never

1.03(0.98,1.08)

1.03(0.98,1.09)

0.88(0.84,0.93)^c

1.46(1.38,1.53)^c

1.45(1.37,1.52)^c

1.02(0.96,1.08)

Formal

1.00(0.94,1.06)

1.00(0.94,1.07)

0.92(0.86,0.98)^b

1.08(1.02,1.15)^a

1.06(1.00,1.13)

1.02(0.95,1.08)

Current (R)

1

1

1

1

1

1

Ethnicity

Bakongo Nod&Sud (R)

1

1

Bas-Kasai et Kwilu-Kwngo

1.20(1.10,1.30)^c

1.10(1.01,1.20)^a

Cuvette central

1.26(1.15,1.38)^c

1.12(1.02,1.23)^a

Ubangi et Itimbiri

1.35(1.24,1.46)^c

1.21(1.11,1.33)^c

Uele Lac Albert

1.20(1.10,1.32)^c

1.09(0.99,1.20)

Basele-K, Man. et Kivu

1.45(1.33,1.57)^c

1.33(1.22,1.44)^c

Kasai, Katanga,Tanganika

1.49(1.38,1.60)^c

1.33(1.23,1.44)^c

Lunda/others

1.22(1.05,1.42)^a

1.14(0.98,1.33)

Amhara (R)

1

1

Oromo

1.51(1.41,1.61)^c

1.38(1.29,1.49)^c

Tigrie

1.15(1.06,1.24)^b

1.17(1.08,1.27)^c

Affar

1.88(1.71,2.06)^c

1.39(1.24,1.56)^c

Somalie

2.31(2.12,2.50)^c

1.91(1.73,2.11)^c

Guragie/others

1.46(1.37,1.56)^c

1.44(1.35,1.54)^c

Residence

Urban (R)

1

1

1

1

Rural

1.28(1.23,1.33)^c

1.15(1.09,1.22)^c

1.82(1.73,1.92)^c

1.21(1.12,1.30)^c

Religion

Christianity (R)

1

1

1

1

Islam

1.08(0.93,1.24)

0.98(0.84,1.13)

1.50(1.44,1.57)^c

1.15(1.08,1.21)^c

Traditionalist/other

1.11(1.00,1.24)

1.04(0.94,1.16)

1.54(1.28,1.85)^c

1.23(1.01,1.48)^a

Age at FB

 < 20 (R)

1

1

1

1

20–24

1.04(0.99,1.08)

1.06(1.01,1.10)^b

0.77(0.74,0.81)^c

0.88(0.84,0.93)^c

 ≥ 25

0.78(0.73,0.84)^c

0.82(0.77,0.88)^c

0.56(0.51,0.61)^c

0.73(0.66,0.79)^c

Wealth index

Low (R)

1

1

1

1

Middle

1.04(0.99,1.08)

1.03(0.99,1.08)

0.87(0.82,0.92)^c

0.99(0.93,1.05)

High

0.80(0.76,0.83)^c

0.97(0.91,1.04)

0.57(0.54,0.60)^c

0.95(0.88,1.02)

Education

No education (R)

1

1

1

1

Primary

1.07(1.02,1.12)^b

1.08(1.03,1.14)^b

0.53(0.50,0.56)^c

0.63(0.60,0.67)^c

Secondary

0.85(0.80,0.89)^c

0.96(0.90,1.02)

0.37(0.33,0.40)^c

0.53(0.48,0.58)^c

Higher

0.49(0.41,0.58)^c

0.71(0.59,0.85)^c

0.33(0.29,0.37)^c

0.53(0.46,0.61)^c

Employment

Not working (R)

1

1

1

1

Working

1.04(0.99,1.09)

0.98(0.93,1.02)

0.81(0.77,0.85)^c

0.95(0.90,0.99)^a

Marital at FB

Never married (R)

1

1

1

1

Married before FB

3.30(2.88,3.77)^c

2.88(2.52,3.30)^c

5.43(3.84,7.68)^c

3.94(2.78,5.58)^c

Married after FB

2.72(2.36,3.14)^c

2.49(2.16,2.88)^c

6.47(4.54,9.23)^c

4.42(3.09,6.31)^c

FB sex

Male (R)

1

1

1

Female

1.01(0.97,1.05)

1.05(1.00,1.10)^a

1.06(1.02,1.11)^b

FB survival

Dead

0.97(0.90,1.05)

1.13(1.02,1.25)^a

1.02(0.92,1.12)

Alive (R)

1

1

1

Deviance (−2ll)

193,721.0^b

191,553.4^c

139,264.8^c

137,602.6^c