Table 1.
Forces required to insert an intrauterine device and to dilate the cervical canal
| Study | Dilator (mm) | Mean force (N) |
|---|---|---|
| Anthony et al12 | Hegar 3 | 2.45 |
| Hegar 4 | 3.43 | |
| Hegar 5 | 8.33 | |
| Hegar 6 | 22.05 | |
| Hegar 7 | 40.42 | |
| Hegar 8 | 41.65 | |
| Nicolaides et al13 | Hegar 3 | 1.3 |
| Hegar 4 | 1.4 | |
| Hegar 5 | 3.4 | |
| Hegar 6 | 12.3 | |
| Hegar 7 | 24.7 | |
| Hegar 8 | 32.4 | |
| Goldstuck11 | Copper-7®* 3.07 | 1.5 |
| Nova T 200®* 3.6 | 2.13 | |
| Progestasert®* 6.1 | 6.5# | |
| Multiload Copper®⋄ 6.5 | 4.04 |
Notes:
*
Presenting diameter of intrauterine device inserter tube
#
one evaluation only
⋄
presenting diameter for all devices in the series (excluding side arms). Copper-7, GD Searle and Co (High Wycombe, UK). Nova T 200, Bayer, (Wuppertal, Germany). Progestasert, (Alza Corporation, Palo Alto, CA, USA). Multiload Copper (MLCu), (Multilan AG, Dublin, Ireland).