Tenaculum Placement for IUD Insertion in Anteflexed Uterus
In a typical anteflexed uterus, apply the tenaculum to the posterior lip (bottom lip as you face the cervix) when there is significant anteflexion. 111
Anatomical Rationale
The key principle is that applying traction to the posterior lip helps straighten a significantly anteflexed uterus, reducing the uterocervical angle and facilitating easier passage of the IUD inserter through the cervical canal. When you grasp the posterior lip and apply gentle downward traction, you're essentially pulling the cervix in a direction that counteracts the forward flexion of the uterine fundus, creating a straighter path 2.
Clinical Decision Algorithm
- Significant anteflexion present: Apply tenaculum to posterior lip
- Minimal or no anteflexion: Apply tenaculum to anterior lip (this is the default for most cases)
The 2025 American Journal of Obstetrics and Gynecology guidelines explicitly state that the tenaculum is "typically [placed on] the anterior lip of the cervix, or the posterior lip if there is significant anteflexion" 111. This represents the most current best-practice guidance.
Mechanism of Action
Research demonstrates that cervical traction with approximately 2 Newtons of force can reduce the median uterocervical angle from 75 degrees to 10 degrees 2. This straightening effect:
- Makes IUD insertion technically easier and safer
- Reduces trauma to the endocervical canal
- Decreases the risk of perforation
- Facilitates smoother passage of the inserter
Pain Management Considerations
When applying the tenaculum to either lip, consider pre-treating with 2 mL of 1% lidocaine injected superficially at the intended tenaculum site immediately before closure 111. This intracervical injection is superior to topical lidocaine gel for reducing tenaculum-related pain 3.
Common Pitfall
The most common error is defaulting to anterior lip placement in all cases without assessing uterine position. Always perform bimanual examination first to determine the degree of anteflexion—if the fundus is significantly anteflexed, posterior lip placement will make your procedure substantially easier and safer.