Table 1 Sample characteristics, and prevalence and factors associated with covert contraceptive use in Kenya (N = 3892)

 Nairobi

394 (10.1)

36

9.9 [7.5–14.1]

1 (Ref)

1 (Ref)

 Bungoma

452 (11.6)

56

12.8 [9.0–17.9]

1.27 [0.75–2.17]

0.376

0.44 [0.21–0.93]

0.031

 Kericho

406 (10.4)

76

16.7 [9.6–27.7]

1.75 [0.84–3.64]

0.135

0.68 [0.27–1.70]

0.404

 Kiambu

313 (8.0)

29

9.5 [5.6–15.4]

0.90 [0.46–1.74]

0.749

0.96 [0.47–1.94]

0.900

 Kilifi

268 (6.9)

27

10.1 [6.3–15.8]

0.97 [0.52–1.82]

0.931

0.31 [0.13–0.69]

0.005

 Kitui

441 (11.3)

48

11.2 [71–18.4]

1.14 [0.59–2.17]

0.698

0.41 [0.20–0.90]

0.025

 Nandi

386 (9.9)

28

7.2 [4.3–11.1]

0.65 [0.35–1.21]

0.177

0.23 [0.10–0.53]

0.001

 Nyamira

410 (10.5)

44

9.2 [6.9–15.0]

0.99 [0.57–1.74]

0.979

0.37 [0.17–0.81]

0.013

 Siaya

288 (7.4)

62

22.9 [16.7–28.1]

2.43 [1.49–3.95]

< 0.001

0.72 [0.36–1.46]

0.363

 Kakamega

415 (10.7)

45

13.1 [7.8–19.6]

1.25 [0.66–2.36]

0.496

0.42 [0.20–0.88]

0.021

 West Pokot

119 (3.1)

14

9.7 [4.2–18.6]

0.87 [0.35–2.12]

0.752

0.30 [0.11–0.84]

0.022

 Urban

1348 (34.6)

110

8.5 [6.7–10.8]

1 (Ref)

1 (Ref)

 Rural

2544 (65.4)

355

13.7 [11.4–16.3]

1.70 [1.22–2.36]

0.002

1.60 [0.99–2.58]

0.055

 15–19

60 (1.5)

4

10.4 [3.0–30.2]

0.79 [0.22–2.91]

0.691

0.46 [0.10–2.18]

0.329

 20–34

2446 (62.9)

282

11.9 [9.9–14.1]

0.92 [0.73–1.16]

0.528

0.92 [0.66–1.30]

0.647

 35–49

1386 (35.6)

179

12.8 [10.7–15.2]

1 (Ref)

1 (Ref)

 No formal

90 (2.3)

20

22.8 [14.9–33.3]

5.46 [2.67–11.2]

< 0.001

3.79 [1.73–8.31]

0.001

 Primary

1997 (51.3)

302

15.0 [12.3–18.3]

3.28 [1.97–5.46]

< 0.001

1.86 [1.06–3.29]

0.032

 Secondary

1234 (31.7)

116

9.8 [7.8–12.2]

2.01 [1.31–3.09]

0.002

1.50 [0.93–2.40]

0.093

 Tertiary

571 (14.7)

27

5.1 [3.4–7.7]

1 (Ref)

1 (Ref)

 Poorest

813 (20.9)

105

18.1 [14.5–22.2]

3.18 [2.16–4.68]

< 0.001

2.67 [1.61–4.45]

< 0.001

 Poorer

809 (20.8)

119

13.3 [10.7–16.4]

2.21 [1.47–3.34]

< 0.001

1.79 [1.05–3.04]

0.032

 Middle

820 (21.1)

120

15.1 [11.7–19.3]

2.57 [1.71–3.86]

< 0.001

2.40 [1.52–3.78]

< 0.001

 Richer

869 (22.3)

72

8.5 [6.5–11.2]

1.35 [0.89–2.05]

0.162

1.19 [0.75–1.89]

0.453

 Richest

579 (14.9)

48

6.5 [4.7–8.8]

1 (Ref)

1 (Ref)

 0–1

640 (17.6)

79

13.1 [10.3–16.4]

1 (Ref)

1 (Ref)

 2–3

1798 (46.2)

162

9.0 [7.1–11.3]

0.66 [0.47–0.91]

0.013

0.49 [0.33–0.72]

< 0.001

 4+

1409 (36.2)

224

15.6 [13.0–18.6]

1.23 [0.91–1.65]

0.167

0.62 [0.40–0.96]

0.033

 No

1815 (50.0)

240

13.3 [11.0–16.1]

1 (Ref)

1 (Ref)

 Yes

1755 (48.3)

189

11.2 [9.2–13.6]

0.82 [0.64–1.05]

0.112

0.88 [0.63–1.22]

0.434

 Infertile

62 (1.7)

8

11.3 [5.9–20.7]

0.83 [0.39–1.78]

0.632

0.71 [0.31–1.63]

0.420

 Age at sexual debut (mean, SD)

17.3 (3.0)

16.6 (2.9)

0.90 [0.86–0.95]

< 0.001

0.94 [0.89–0.99]

0.029