Preterm ruptured membranes split into four groups with very different sepsis risk

Design

Single-centre cohort with amniocentesis at admission

Population

961 singleton pregnancies with preterm prelabour rupture of membranes, 23–36 weeks

Primary outcome

Prevalence of four intra-amniotic categories; early-onset neonatal sepsis

Effect

Intra-amniotic infection 17%; early sepsis 12% vs 2% in negative fluid; aOR 3.4 (95% CI 1.7–7.0)

A Czech tertiary unit offered transabdominal amniocentesis at admission to women with preterm prelabour rupture of membranes between 23 and 36 weeks, and classified 961 pregnancies by amniotic fluid interleukin-6 and by culture plus molecular testing for microbes.

Intra-amniotic infection (inflammation with microbes) was found in 17%, sterile inflammation in 7%, microbes without inflammation in 11%, and neither in 65%. Early-onset neonatal sepsis occurred in 12% of babies from the infection group against 2% where fluid was negative for both. After adjustment, infection carried about three times the odds of early sepsis. Ureaplasma made up nearly two-thirds of microbial detections, and other bacteria were linked to worse outcomes than Ureaplasma alone. Fluid was obtained in 98% of attempted taps.

This is observational and from one centre with long experience of the procedure. It shows that the label preterm rupture hides very different pregnancies, but it does not show that sampling the fluid and acting on the result improves outcomes; that needs a trial. Routine amniocentesis in preterm rupture is not standard in most guidelines, and this study does not change that.

• Preterm rupture of membranes is not one condition: about one in six had established intra-amniotic infection in this cohort.
• Babies from pregnancies with intra-amniotic infection had early-onset sepsis in about 12% of cases.
• Ureaplasma was the commonest organism; other bacteria carried the worse outcomes.
• Where amniocentesis is offered, the tap succeeded in 98% of attempts in experienced hands.
• Tell the neonatal team when there are clinical signs of chorioamnionitis, as those babies carry the highest sepsis risk.

Why it matters

Sorting by amniotic fluid may one day guide who needs delivery and who can wait.

Don't overread it

It shows risk differs by category, not that testing the fluid and acting on it improves outcomes.

The statistics, in plain English

An adjusted odds ratio of 3.4 (95% CI 1.7–7.0) means babies in the infection group had roughly three times the odds of early sepsis after accounting for other factors; the whole interval is well above 1. The unadjusted percentages (12% vs 2%) give a feel for the absolute gap. Because this is one experienced centre, the tap success rate may be higher than elsewhere.

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