Transverse Lie: Delivery & Management

Definition & Terminology

Incidence & Associated Conditions

• Occurs in approximately 1 in 300 deliveries
• Associated conditions (from Cruikshank & White's series of 118 cases):
  • Prematurity — 38%
  • Grand multiparity (≥3 prior deliveries) — 87%
  • Premature rupture of membranes (PROM) — 30%
  • Placenta previa — 10%
• Other predisposing factors: polyhydramnios, uterine anomalies, pelvic tumors/fibroids, contracted pelvis, multiple gestation

Perinatal Risks

• Perinatal mortality: 3.9%–24% — largely driven by prematurity in low-birth-weight infants
• Cord prolapse — major catastrophic risk, especially with spontaneous membrane rupture outside hospital
• Neglected/impacted shoulder — if labor progresses unrecognized: uterine rupture, maternal death
• Patients often present after spontaneous membrane rupture with a severely asphyxiated or dead fetus

Diagnosis

• Clinical palpation: fundus and lower uterine segment feel empty; fetal head palpable laterally on one side, breech on the other
• Vaginal exam: no presenting part in pelvis (unless shoulder/arm has prolapsed)
• Ultrasound: confirms diagnosis, determines back position (back-up vs back-down), placental location, amniotic fluid, fetal size

Classification by Fetal Position

Management — Decision Algorithm

⚠️ Key Factors Governing Management

1. Gestational age / expected fetal weight
2. Membrane status (intact vs ruptured)
3. Presence of placenta previa or CPD
4. Fetal mobility (restricted by advanced labor or oligohydramnios?)
5. Parity and cervical status

A. Previable Fetus (<600 g / periviable gestational age)

• No immediate intervention required for delivery
• Attempt tocolysis to increase fetal weight and maturity
• Fetus eventually delivers vaginally via conduplicato corpore (fetus folds on itself, body doubles upon itself) — does not cause undue maternal trauma at very low birth weights

B. Viable / Near-Term Fetus (chance of survival >10%)

Before Labor / Preterm (<36–37 weeks), Membranes Intact:

• External version not recommended before 36–37 weeks — risk of precipitating premature labor
• Admit to hospital; monitor closely
• Consider stabilizing induction after version at ≥38 weeks (see below)

At or Beyond 37 Weeks — "Unstable Lie" Protocol:

• Admitted all patients ≥37 weeks with unstable lie
• Excluded CPD and placenta previa
• Performed external cephalic version (ECV) → then induced labor
• Results: 86/102 delivered vaginally; only 1 cord prolapse, 0 perinatal deaths
• Compare: 50 cases where spontaneous labor was awaited → 10 cord prolapses, 4 perinatal deaths

C. External Cephalic Version (ECV)

• Placenta previa / vasa previa
• PROM or oligohydramnios
• Nuchal cord on ultrasound
• Prior classical cesarean or significant uterine surgery
• Obvious CPD
• Active labor with ruptured membranes
• Fetal distress / non-reactive NST

D. Cesarean Delivery (Abdominal Delivery)

• Fetal mobility restricted (advanced labor, oligohydramnios/PROM)
• Placenta previa
• CPD
• Failed ECV with any indication for delivery
• Viable fetus in active labor with transverse lie

Using a low transverse incision when possible reduces acute puerperal complications and preserves future TOLAC (trial of labor after cesarean) eligibility. However, fetal safety always takes priority over incision choice.

E. Emergency/Neglected Transverse Lie

• Cord prolapse must be immediately excluded
• If fetus is dead: depending on parity and cervical dilation, a destructive operation (embryotomy) may be performed in certain settings
• If fetus is alive and viable: immediate cesarean (classical incision likely required)
• Internal podalic version is now rarely performed — reserved for a second twin in transverse lie (not for singleton term pregnancies)

Summary Algorithm

Transverse Lie Identified
         │
    Gestational Age?
    ┌────┴────┐
<Viable     >37 weeks / Viable
    │              │
  Expectant    Admit; exclude CPD, previa
  management        │
                ECV feasible?
              ┌───┴───┐
            Yes        No (placenta previa,
              │        PROM, advanced labor)
         ECV → Induction          │
              │               Cesarean
         Success?          (choose incision
         ┌──┴──┐           based on back position)
       Yes    No
         │      │
    Vaginal   Cesarean
    delivery

Key Points to Remember

1. Grand multiparity + prematurity are the strongest associations
2. Cord prolapse is the most feared acute complication — always rupture membranes with the fetus controlled
3. ECV success rate ~90% in transverse lie — the highest of any malpresentation
4. Hospital admission at ≥37 weeks with unstable lie dramatically reduces cord prolapse deaths
5. Back-down transverse lie at cesarean → classical uterine incision usually needed
6. Conduplicato corpore applies only to very immature fetuses (<600 g) — never for viable term infants