Prophylactic cefazolin in amnioinfusions administered for meconium-stained amniotic fluid

Antibiotics for neonates born through meconium-stained amniotic fluid

BACKGROUND

Approximately 1 in 10 pregnancies is affected by meconium passage at delivery, which can result in meconium aspiration syndrome (MAS). MAS can cause respiratory complications and, very rarely, death. Antibiotics have been prescribed for neonates exposed to meconium in amniotic fluid, with the intention of preventing infection due to potential bacterial contaminants.

OBJECTIVES

We conducted this review to assess the efficacy and safety of antibiotics for:1. prevention of infection, morbidity, and mortality among infants born through meconium-stained amniotic fluid (MSAF) who are asymptomatic at birth; and2. prevention of infection, morbidity, and mortality among infants born through MSAF who have signs and symptoms compatible with meconium aspiration syndrome (MAS).

SEARCH METHODS

We performed a literature search using the following databases: MEDLINE (1966 to July 2016); Embase (1980 to July 2016); the Cumulative Index to Nursing and Allied Health Literature (CINAHL; 1982 to July 2016); and the Cochrane Central Register of Controlled Trials (CENTRAL; 2016, Issue 7) in the Cochrane Library. We also searched clinical trials databases, conference proceedings, and reference lists of retrieved articles.

SELECTION CRITERIA

We included randomised and quasi-randomised controlled trials that compared antibiotics administered via any route versus placebo or no treatment for prevention of infection among neonates exposed to MSAF, or who developed MAS. We excluded cohort, case control, and any other non-randomised studies and applied no language restrictions. We included studies of term and preterm infants, and we included studies examining use of any antibacterial antibiotics. We included studies that reported on any outcomes of interest.

DATA COLLECTION AND ANALYSIS

We assessed the methodological quality of included trials by reviewing information provided in study reports and obtained by personal communication with study authors. We extracted data on relevant outcomes, estimated effect size, and reported values as risk ratios (RRs), risk differences (RDs), and mean differences (MDs), as appropriate. We conducted subgroup analyses for treatment of MAS and for prophylaxis (asymptomatic neonates exposed to meconium).

MAIN RESULTS

Four randomised controlled studies including a total of 695 participants were eligible for inclusion. Three studies evaluated neonates with MAS, and one study assessed asymptomatic neonates exposed to meconium in amniotic fluid. These studies exhibited varying degrees of methodological rigour: Two studies were at low risk of bias, and two were at unclear risk. We graded evidence derived from these studies as low quality. We downgraded overall evidence owing to the large number of participants lost to follow-up in one trial, the small sample sizes of all trials, and unclear methodological details provided for two trials.The primary outcome was risk of early- and late-onset neonatal sepsis. Antibiotics did not decrease the risk of sepsis in neonates with a diagnosis of MAS (RR 1.54, 95% confidence interval (CI) 0.27 to 8.96; RD 0.00, 95% CI -0.02 to 0.03; 445 participants, three studies; I² = 0%) nor in asymptomatic neonates exposed to meconium in amniotic fluid (RR 0.76, 95% CI 0.25 to 2.34; RD -0.01, 95% CI -0.07 to 0.04; 250 participants, one study; I² = 0%). Results show no significant differences in mortality or duration of stay in hospital between groups given antibiotics and control groups of symptomatic and asymptomatic neonates. One study in asymptomatic neonates reported a significant reduction in duration of mechanical ventilation for the control group compared with the antibiotic group (MD 0.26, 95% CI 0.15 to 0.37; 250 participants, one study; I² = 0%).

AUTHORS' CONCLUSIONS

Upon review of available evidence, we found no differences in infection rates following antibiotic treatment among neonates born through meconium-stained fluid and those with meconium aspiration syndrome. The overall quality of evidence is low owing to the small number of included studies. Well-controlled studies of adequate power are needed.

Antibiotics for meconium-stained amniotic fluid in labour for preventing maternal and neonatal infections

BACKGROUND

Chorioamnionitis is more likely to occur when meconium-stained amniotic fluid (MSAF) is present. Meconium may enhance the growth of bacteria in amniotic fluid by serving as a growth factor, inhibiting bacteriostatic properties of amniotic fluid. Many adverse neonatal outcomes related to MSAF result from meconium aspiration syndrome (MAS). MSAF is associated with both maternal and newborn infections. Antibiotics may be an effective option to reduce such morbidity.

OBJECTIVES

The objective of this review is to assess the efficacy and side effects of prophylactic antibiotics for MSAF during labour in preventing maternal and neonatal infections.

SEARCH METHODS

We searched the Cochrane Pregnancy and Childbirth Group's Trials Register (30 September 2014). 

SELECTION CRITERIA

Randomised controlled trials (RCTs) comparing prophylactic antibiotics with placebo or no treatment during labour for women with MSAF.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed trials for inclusion and risk of bias, extracted data and checked them for accuracy.

MAIN RESULTS

We included two studies with 362 pregnant women. Both studies compared ampicillin-sulbactam (N = 183) versus normal saline (N = 179) in pregnant women with MSAF. Prophylactic antibiotics appeared to have no statistically significant reduction in the incidence of neonatal sepsis (risk ratio (RR) 1.00, 95% CI 0.21 to 4.76), neonatal intensive care unit (NICU) admission (RR 0.83, 95% CI 0.39 to 1.78) and postpartum endometritis (RR 0.50, 95% CI 0.18 to 1.38). However, there was a significant decrease in the risk of chorioamnionitis (RR 0.36, 95% CI 0.21 to 0.62). No serious adverse effects were reported. Drug resistance, duration of mechanical ventilation and duration of admission to NICU/hospital were not reported. Most of the domains for risk of bias were at low risk of bias for one study and at unclear risk of bias for the other study. The quality of the evidence using GRADE was low for neonatal sepsis, postpartum endometritis, and neonatal mortality and morbidity prior to discharge (Neonatal intensive care admissions) and of moderate quality for chorioamnionitis.

AUTHORS' CONCLUSIONS

Current evidence indicates that compared to placebo, antibiotics for MSAF in labour may reduce chorioamnionitis. There was no evidence that antibiotics could reduce postpartum endometritis, neonatal sepsis and NICU admission. This systematic review identifies the need for more well-designed, adequately powered RCTs to assess the effect of prophylactic antibiotics in the incidence of maternal and neonatal complications.

Amnioinfusion for meconium-stained liquor in labour

BACKGROUND

Amnioinfusion is thought to dilute meconium present in the amniotic fluid and so reduce the risk of meconium aspiration.

OBJECTIVES

To assess the effects of amnioinfusion for meconium-stained liquor on perinatal outcome.

SEARCH METHODS

We searched the Cochrane Pregnancy and Childbirth Group's Trials Register (1 December 2013).

SELECTION CRITERIA

Randomised trials comparing amnioinfusion with no amnioinfusion for women in labour with moderate or thick meconium staining of the amniotic fluid.

DATA COLLECTION AND ANALYSIS

Three review authors independently assessed eligibility and trial quality, and extracted data.

MAIN RESULTS

Fourteen studies of variable quality (4435 women) are included.Subgroup analysis was performed for studies from settings with limited facilities to monitor the baby's condition during labour and intervene effectively, and settings with standard peripartum surveillance.Settings with standard peripartum surveillance: there was considerable heterogeneity for several outcomes. There was no significant reduction in the primary outcomes meconium aspiration syndrome, perinatal death or severe morbidity, and maternal death or severe morbidity. There was a reduction in caesarean sections (CSs) for fetal distress but not overall. Meconium below the vocal cords diagnosed by laryngoscopy was reduced, as was neonatal ventilation or neonatal intensive care unit admission, but there was no significant reduction in perinatal deaths or other morbidity. Planned sensitivity analysis excluding trials with greater risk of bias resulted in an absence of benefits for any of the outcomes studied.Settings with limited peripartum surveillance: three studies were included. In the amnioinfusion group there was a reduction in CS for fetal distress and overall; meconium aspiration syndrome (three studies, 1144 women; risk ratio (RR) 0.17, 95% confidence interval (CI) 0.05 to 0.52); perinatal mortality (three studies, 1151 women; RR 0.24, 95% CI 0.11 to 0.53) and neonatal ventilation or neonatal intensive care unit admission. In one of the studies, meconium below the vocal cords was reduced and, in the other, neonatal encephalopathy was reduced.

AUTHORS' CONCLUSIONS

Amnioinfusion is associated with substantive improvements in perinatal outcome only in settings where facilities for perinatal surveillance are limited. It is not clear whether the benefits are due to dilution of meconium or relief of oligohydramnios.In settings with standard peripartum surveillance, some non-substantive outcomes were improved in the initial analysis, but sensitivity analysis excluding trials with greater risk of bias eliminated these differences. Amnioinfusion is either ineffective in this setting, or its effects are masked by other strategies to optimise neonatal outcome.The trials reviewed are too small to address the possibility of rare but serious maternal adverse effects of amnioinfusion.

Amnioinfusion for meconium-stained liquor

Amnioinfusion reduces the risk of meconium aspiration by the infants of women with thick meconium staining of the amniotic fluid. The benefits are clear in facilities with high baseline rates of meconium aspiration, and are therefore likely to outweigh the risk of uncommon but serious maternal side-effects. Larger randomized trials are needed to determine more precisely the relative risks and benefits in facilities with low baseline rates of meconium aspiration. The addition of antibiotics to the infusate has not been shown to reduce the risk of sepsis related to meconium.