In a term pregnancy with a confirmed transverse lie requiring cesarean delivery, what is the recommended management of the uterine incision, including how placental location influences the choice between a classical vertical incision and a low transverse incision?

Management of Transverse Lie During Cesarean Section

In term pregnancies with transverse lie, a low transverse uterine incision should be attempted first, with the decision to convert to a classical vertical incision made only after intraoperative inspection reveals that safe fetal delivery cannot be accomplished through the transverse approach. 1, 2

Preoperative Planning

Defer the final decision on incision type until after direct visualization of the uterus intraoperatively. 3 The key principle is that you cannot reliably predict which cases will require extension or conversion until you see:

• The actual placental location 4
• The degree of lower segment development 5
• The fetal position and accessibility 2

Initial Surgical Approach

Start with Low Transverse Incision

Make a wider-than-usual low transverse uterine incision (consider 3-4 cm initial incision rather than the standard 2-3 cm) to facilitate fetal manipulation. 6, 2 This provides adequate room for the internal maneuvers required to deliver a transverse lie.

• Use blunt expansion after the initial incision to reduce blood loss by approximately 55 mL 6
• The transverse incision is safe for transverse lie delivery in 92.4% of cases 1

Identify the Presenting Part First

After entering the uterine cavity, immediately identify which fetal part is presenting and guide it toward the incision opening. 2 This is critical because:

• Delivering the presenting part first is the fundamental rule of fetal extraction 2
• Attempting to deliver a non-presenting part increases risk of uterine extension and fetal injury 2

Delivery Technique Through Transverse Incision

Perform internal version to convert the transverse lie to breech, then execute breech extraction. 7 The "intra-abdominal version technique" allows successful delivery through a low transverse incision in most cases:

1. Grasp one or both fetal feet through the uterine incision 4
2. Apply traction to deliver the legs and convert to breech presentation 7
3. Complete delivery using standard breech extraction maneuvers 4, 2

This approach avoids the need for classical cesarean section while maintaining the safety advantages of a low segment incision. 7

When to Convert to Classical or Vertical Incision

Convert to a classical vertical incision if any of the following conditions are encountered after uterine inspection: 8, 5, 3

Absolute Indications for Conversion:

• Anterior placenta previa/accreta overlying the lower segment - The uterine incision must avoid the placenta whenever possible to prevent catastrophic hemorrhage 4
• Inadequate lower segment development (particularly in preterm gestations) - Limited access makes safe transverse delivery impossible 5, 3
• Dense adhesions preventing safe access to lower segment 5, 2
• Obstructing cervical myoma or other pelvic mass 2

Relative Indications Requiring Intraoperative Judgment:

• Presenting part remains high and inaccessible despite adequate incision 3
• Inability to safely grasp fetal parts for internal version 2
• Risk of significant uterine injury during attempted extraction through transverse incision 2

Management of Incision Extensions

If the transverse incision proves inadequate during delivery, immediately convert to an inverted T-shaped or J-shaped extension rather than forcing delivery through an insufficient opening. 2

• Inverted-T extensions occur in approximately 7.6% of transverse lie cases 1
• Fetuses requiring T-extension have lower 1-minute Apgar scores (6.0 vs 7.5) but equivalent 5-minute scores 1
• Forcing delivery through an inadequate incision risks injury to the cervix, vagina, bladder, ureters, and parametrial vessels 2

Placental Location Considerations

When anterior placenta previa or accreta is identified on preoperative imaging or confirmed at laparotomy, plan for a classical vertical incision from the outset. 4, 8

The rationale is straightforward:

• Incising through the placenta causes immediate, often uncontrollable hemorrhage 4
• A vertical incision in the upper uterine segment avoids the placenta-occupied lower segment 4
• This approach is particularly critical in placenta accreta spectrum where attempts at placental removal trigger massive bleeding 4

Uterine Closure Technique

Close the hysterotomy in two layers regardless of whether you used transverse or vertical incision. 4 While evidence is not definitive, two-layer closure may reduce uterine rupture risk in subsequent pregnancies. 4

For classical incisions specifically:

• Closure is technically more difficult than transverse incisions 5
• Requires meticulous technique to minimize hemorrhage and adhesion formation 5
• Speed and skill are mandatory given the increased vascularity of the upper segment 5

Critical Counseling for Future Pregnancies

If a classical incision was performed, the patient is absolutely contraindicated for trial of labor in any future pregnancy. 5 The risk of catastrophic uterine rupture in the contractile corpus is unacceptably high. 5

For low vertical incisions, counsel patients about increased (though lower than classical) rupture risk and recommend detailed early ultrasound in subsequent pregnancies to assess implantation site. 8, 3

Common Pitfalls to Avoid

• Never commit to incision type based solely on preoperative imaging - Always inspect the uterus directly before making the final decision 3
• Do not attempt to force delivery through an inadequate transverse incision - This causes more maternal and fetal morbidity than planned conversion 2
• Avoid making the initial transverse incision too small - A wider initial incision (3-4 cm) facilitates the internal manipulations required for transverse lie 2
• Do not incise through an anterior placenta - If discovered intraoperatively, convert to vertical incision immediately 4