Table 2
Comparison of woman's age with frequency of checking intrauterine device threads
Age (years)
Frequency of checking
Never
Once
2–3 times
4–6 times
>7 times
<20
0
0
0
1
0
21–30
12
1
7
3
6
31–40
23
3
6
2
4
>40
16
5
4
3
4