Which statement regarding mechanical methods for cervical ripening is false: they often require oxytocin to achieve labor, there is no increase in maternal infection, they can cause release of local prostaglandins (PG), or they have similar effectiveness compared to vaginal prostaglandins (PG)?

Mechanical Methods for Cervical Ripening: False Statement Identification

The false statement regarding mechanical methods for cervical ripening is that "there is no increase in maternal infection." Mechanical methods for cervical ripening can be associated with an increased risk of maternal infection compared to other methods.

Analysis of Each Statement

1. Often require oxytocin to achieve labour - TRUE

Mechanical methods for cervical ripening typically prepare the cervix but often need additional oxytocin to establish active labor:

• Mechanical methods primarily work on cervical ripening but frequently require oxytocin augmentation to achieve active labor 1
• The European Society of Cardiology (ESC) guidelines note that mechanical methods like Foley catheters are preferable for cervical ripening in certain high-risk patients, but labor induction often still requires oxytocin 2

2. There is no increase in maternal infection - FALSE

This statement is incorrect for several reasons:

• Mechanical methods involve introducing foreign objects (catheters, dilators) into the cervical canal, which creates a potential pathway for infection
• The Cochrane review on mechanical methods for labor induction specifically mentions that "special attention should be paid to... risk of infection" when using these devices 1
• Vaginal delivery is generally associated with less infection risk compared to cesarean delivery, but this doesn't mean mechanical methods themselves carry no infection risk 2

3. Can cause release of local prostaglandins - TRUE

Mechanical methods do stimulate the release of endogenous prostaglandins:

• Mechanical dilators and balloon catheters work partly by causing local tissue pressure and stretching, which triggers the release of endogenous prostaglandins from cervical and decidual cells
• This mechanism contributes to their effectiveness in cervical ripening 3

4. Similar effectiveness for cervical ripening compared to vaginal prostaglandins - TRUE

Evidence supports comparable effectiveness between mechanical methods and prostaglandins:

• The Cochrane review found that mechanical methods have similar effectiveness to prostaglandins for cervical ripening 1
• A 2020 study comparing Foley catheter to prostaglandins in multiparous women found similar success rates for cervical ripening 4
• Another study comparing double-balloon catheter versus prostaglandins found no significant difference in cesarean delivery rates (42.5% vs 42.7%) 5

Key Advantages of Mechanical Methods

1. Lower risk of uterine hyperstimulation:

   • Mechanical methods significantly reduce the risk of hyperstimulation with fetal heart rate changes compared to prostaglandins 1
   • This makes them particularly valuable in high-risk scenarios like previous cesarean delivery

2. Cost-effectiveness:

   • Mechanical methods are generally less expensive than pharmacological options 3
   • ACOG notes significant cost differences between prostaglandins and mechanical methods 2

3. Safety profile in specific populations:

   • Particularly useful in patients with previous cesarean delivery where prostaglandins increase uterine rupture risk 6
   • ESC guidelines recommend mechanical methods as preferable for patients with cyanosis 2

Clinical Applications and Considerations

• Previous cesarean delivery: Mechanical methods are preferred over prostaglandins due to lower risk of uterine rupture 6
• Unfavorable cervix: Both mechanical and pharmacological methods are effective, but mechanical methods have fewer systemic side effects 3
• High-risk patients: In patients with cyanosis or cardiovascular disease, mechanical methods may be safer as they cause less systemic effects 2

Potential Pitfalls and Contraindications

• Infection risk: Proper aseptic technique is essential when placing mechanical devices
• Contraindications: Low-lying placenta is a contraindication for mechanical methods 1
• Patient discomfort: Insertion of mechanical devices may cause maternal discomfort 1

In summary, while mechanical methods for cervical ripening are effective and have several advantages including reduced risk of uterine hyperstimulation, they do carry some risk of maternal infection, making the statement "there is no increase in maternal infection" false.