Second-twin caesarean linked to three times the severe neonatal morbidity

Design

Planned secondary analysis of a national prospective population-based cohort

Population

3,905 second twins at ≥32 weeks after vaginal birth of the first twin, 176 French units

Primary outcome

Severe neonatal morbidity and mortality

Effect

8.9% vs 2.5%; aRR 3.17 (95% CI 1.58–6.40)

A planned secondary analysis of JUMODA, a French national prospective cohort of twin births across 176 maternity units in 2014–2015, looked at 3,905 second twins born at 32 weeks or later after vaginal birth of the first twin.

The second twin was delivered by caesarean in 124 cases (3.2%). Severe neonatal morbidity or death occurred in 8.9% of these against 2.5% after vaginal birth (adjusted RR 3.17, 95% CI 1.58–6.40), and the picture was similar in a low-risk subgroup (aRR 4.03). No neuraxial analgesia (aRR 2.13), transverse lie of the second twin (aRR 2.11) and units delivering fewer than 50 twin pairs a year (aRR 1.58) were associated with needing the caesarean; breech presentation was associated with a lower risk (aRR 0.47).

The event count is small and some of the excess will reflect why the caesarean was needed, such as fetal distress. Even so, the risk factors identified are ones a team can act on before the first twin is born.

• Offer an epidural early to women planning vaginal twin birth, so internal manoeuvres remain possible.
• Confirm the second twin's presentation with ultrasound immediately after the first is born.
• Have a clinician skilled in internal podalic version and breech extraction present at twin births.
• Consider where twin births are planned: low-volume units had more second-twin caesareans.

Why it matters

The modifiable risk factors — no epidural, transverse lie, low unit volume — are decided before the second stage begins.

Don't overread it

Observational and based on few events — the caesarean may be a marker of the emergency rather than its cause.

The statistics, in plain English

An adjusted relative risk of 3.17 means about three times the risk after accounting for measured differences. The wide interval (1.58 to 6.40) reflects only 11 events in the caesarean group, so the true size could be much smaller or larger.

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