Amnioinfusion

Interventions for Intrauterine Resuscitation in Suspected Fetal Distress During Term Labor: A Systematic Review

IMPORTANCE

Intrauterine resuscitation techniques during term labor are commonly used in daily clinical practice. Evidence, however, to support the beneficial effect of intrauterine resuscitation techniques on fetal distress during labor is limited and sometimes contradictory. In contrast, some of these interventions may even be harmful.

OBJECTIVE

To give insight into the current evidence on intrauterine resuscitation techniques. In addition, we formulate recommendations for current clinical practice and propose directions for further research.

EVIDENCE ACQUISITION

We systematically searched the electronic PubMed, EMBASE, and CENTRAL databases for studies on intrauterine resuscitation for suspected fetal distress during term labor until February 2015. Eligible articles and their references were independently assessed by 2 authors. Judgment was based on methodological quality and study results.

RESULTS

Our literature search identified 15 studies: 4 studies on amnioinfusion, 1 study on maternal hyperoxygenation, 1 study on maternal repositioning, 1 study on intravenous fluid administration, and 8 studies on tocolysis. Of these 15 research papers, 3 described a randomized controlled trial; all other studies were observational reports or case reports.

CONCLUSIONS AND RELEVANCE

Little robust evidence to promote a specific intrauterine resuscitation technique is available. Based on our literature search, we support the use of tocolysis and maternal repositioning for fetal distress. We believe the effect of amnioinfusion and maternal hyperoxygenation should be further investigated in properly designed randomized controlled trials to make up the balance between beneficial and potential hazardous effects.

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.

Prophylactic versus therapeutic amnioinfusion for oligohydramnios in labour

BACKGROUND

Amnioinfusion aims to relieve umbilical cord compression during labour by infusing a liquid into the uterine cavity.

OBJECTIVES

The objective of this review was to assess the effects of prophylactic amnioinfusion for women in labour with oligohydramnios, but not fetal heart deceleration, compared with therapeutic amnioinfusion only if fetal heart rate decelerations or thick meconium-staining of the liquor occur.

SEARCH METHODS

We searched the Cochrane Pregnancy and Childbirth Group's Trials Register (28 February 2012).

SELECTION CRITERIA

Randomised trials comparing prophylactic amnioinfusion in women in labour with oligohydramnios but not fetal heart rate deceleration in labour with therapeutic amnioinfusion.

DATA COLLECTION AND ANALYSIS

The authors assessed trial quality and extracted data.

MAIN RESULTS

One randomized trial of 116 women was included. No differences were found in the rate of caesarean section (risk ratio 1.29, 95% confidence interval 0.60 to 2.74). There were no differences in cord arterial pH, oxytocin augmentation, neonatal pneumonia or postpartum endometritis. Prophylactic amnioinfusion was associated with increased intrapartum fever (risk ratio 3.48, 95% confidence interval 1.21 to 10.05).

AUTHORS' CONCLUSIONS

There appears to be no advantage of prophylactic amnioinfusion over therapeutic amnioinfusion carried out only when fetal heart rate decelerations or thick meconium-staining of the liquor occur.

Amnioinfusion for potential or suspected umbilical cord compression in labour

BACKGROUND

Amnioinfusion aims to prevent or relieve umbilical cord compression during labour by infusing a solution into the uterine cavity.

OBJECTIVES

To assess the effects of amnioinfusion for potential or suspected umbilical cord compression on maternal and perinatal outcome .

SEARCH METHODS

We searched the Cochrane Pregnancy and Childbirth Group's Trials Register (31 October 2011).

SELECTION CRITERIA

Randomised trials of amnioinfusion compared with no amnioinfusion in women with babies at risk of umbilical cord compression in labour.

DATA COLLECTION AND ANALYSIS

The original review had one author only (Justus Hofmeyr (GJH)). For this update, two authors (GJH and T Lawrie) assessed 13 additional trial reports for eligibility and quality. We extracted data and checked for accuracy.

MAIN RESULTS

We have included 19 studies, with all but two studies having fewer than 200 participants. Transcervical amnioinfusion for potential or suspected umbilical cord compression was associated with the following reductions: caesarean section overall (13 trials, 1493 participants; average risk ratio (RR) 0.62, 95% confidence interval (CI) 0.46 to 0.83); fetal heart rate (FHR) decelerations (seven trials, 1006 participants; average RR 0.53, 95% CI 0.38 to 0.74); Apgar score less than seven at five minutes (12 trials, 1804 participants; average RR 0.47, 95% CI 0.30 to 0.72); meconium below the vocal cords (three trials, 674 participants, RR 0.53, 95% CI 0.31 to 0.92); postpartum endometritis (six trials, 767 participants; RR 0.45, 95% CI 0.25 to 0.81) and maternal hospital stay greater than three days (four trials, 1051 participants; average RR 0.45, 95% CI 0.25 to 0.78). Transabdominal amnioinfusion showed similar trends, though numbers studied were small.Mean cord umbilical artery pH was higher in the amnioinfusion group (seven trials, 855 participants; average mean difference 0.03, 95% CI 0.00 to 0.06) and there was a trend toward fewer neonates with a low cord arterial pH (less than 7.2 or as defined by trial authors) in the amnioinfusion group (eight trials, 972 participants, average RR 0.58, 95% CI 0.29 to 1.14).

AUTHORS' CONCLUSIONS

The use of amnioinfusion for potential or suspected umbilical cord compression may be of considerable benefit to mother and baby by reducing the occurrence of variable FHR decelerations, improving short-term measures of neonatal outcome, reducing maternal postpartum endometritis and lowering the use of caesarean section, although there were methodological limitations to the trials reviewed here. In addition, the trials are too small to address the possibility of rare but serious maternal adverse effects of amnioinfusion. More research is needed to confirm the findings, assess longer-term measures of fetal outcome, and to assess the impact on caesarean section rates when the diagnosis of fetal distress is more stringent. Trials should assess amnioinfusion in specific clinical situations, such as FHR decelerations, oligohydramnios or prelabour rupture of membranes.

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 STRATEGY

We searched the Cochrane Pregnancy and Childbirth Group's Trials Register (May 2009).

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

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

MAIN RESULTS

Thirteen studies of variable quality (4143 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: two studies (855 women) were included. In the amnioinfusion group there was a reduction in CS for fetal distress and overall; meconium aspiration syndrome (RR 0.25, 95% CI 0.13 to 0.47), and neonatal ventilation or neonatal intensive care unit admission; and a trend towards reduced perinatal mortality (RR 0.37, 95% CI 0.13 to 1.01). 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.

WITHDRAWN: Amnioinfusion for meconium-stained liquor in labour

BACKGROUND

Amnioinfusion aims to prevent or relieve umbilical cord compression during labour by infusing a solution into the uterine cavity. It is also thought to dilute meconium when present in the amniotic fluid and so reduce the risk of meconium aspiration. However, it may be that the mechanism of effect is that it corrects oligohydramnios (reduced amniotic fluid), for which thick meconium staining is a marker.

OBJECTIVES

The objective of this review was to assess the effects of amnioinfusion for meconium-stained liquor on perinatal outcome.

SEARCH STRATEGY

The Cochrane Pregnancy and Childbirth Group trials register (October 2001) and the Cochrane Controlled Trials Register (Issue 3, 2001) were searched.

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

Eligibility and trial quality were assessed by one reviewer.

MAIN RESULTS

Twelve studies, most involving small numbers of participants, were included. Under standard perinatal surveillance, amnioinfusion was associated with a reduction in the following: heavy meconium staining of the liquor (relative risk 0.03, 95% confidence interval 0.01 to 0.15); variable fetal heart rate deceleration (relative risk 0.65, 95% confidence interval 0.49 to 0.88); and reduced caesarean section overall (relative risk 0.82, 95% confidence interval 0.69 to 1.97). No perinatal deaths were reported. Under limited perinatal surveillance, amnioinfusion was associated with a reduction in the following: meconium aspiration syndrome (relative risk 0.24, 95% confidence interval 0.12 to 0.48); neonatal hypoxic ischaemic encephalopathy (relative risk 0.07, 95% confidence interval 0.01 to 0.56) and neonatal ventilation or intensive care unit admission (relative risk 0.56, 95% confidence interval 0.39 to 0.79); there was a trend towards reduced perinatal mortality (relative risk 0.34, 95% confidence interval 0.11 to 1.06).

AUTHORS' CONCLUSIONS

Amnioinfusion is associated with improvements in perinatal outcome, particularly in settings where facilities for perinatal surveillance are limited. The trials reviewed are too small to address the possibility of rare but serious maternal adverse effects of amnioinfusion.

Sacrococcygeal teratoma: prenatal assessment, fetal intervention, and outcome

PURPOSE

To understand the natural history and define indications for fetal intervention in sacrococcygeal teratoma (SCT), the authors reviewed all cases of fetal SCT presenting for evaluation.

METHODS

Prenatal diagnostic studies including ultrasound scan, magnetic resonance imaging (MRI), echocardiography and pre- and postnatal outcomes were reviewed in 30 cases of SCT that presented between September 1995 and January 2003.

RESULTS

The mean gestational age (GA) at presentation was 23.9 weeks (range, 19 to 38.5) with 3 sets of twins (10%). Overall outcomes included 4 terminations, 5 fetal demises, 7 neonatal deaths, and 14 survivors. Significant obstetric complications occurred in 81% of the 26 continuing pregnancies: polyhydramnios (n = 7), oligohydramnios (n = 4), preterm labor (n = 13), preeclampsia (n = 4), gestational diabetes (n = 1), HELLP syndrome (n = 1), and hyperemesis (n = 1). Fetal intervention included cyst aspiration (n = 6), amnioreduction (n = 3), amnioinfusion (n = 1), and open fetal surgical resection (n = 4). Indications for cyst aspiration and amnioreduction were maternal discomfort, preterm labor, and prevention of tumor rupture at delivery. Although 15 SCTs were solid causing risk for cardiac failure, only 4 fetuses met criteria for fetal debulking based on ultrasonographic and echocardiographic evidence of impending high output failure and favorable anatomy at 21, 23.6, 25, and 26 weeks' gestation. Intraoperative events included maternal blood transfusion (n = 1), fetal blood transfusion (n = 2), chorioamniotic membrane separation (n = 2), and fetal arrest requiring successful cardiopulmonary resuscitation (CPR) (n = 1). In the fetal resection group, 3 of 4 survived with mean GA at delivery of 29 weeks (range, 27.6 to 31.7 weeks), mean birth weight of 1.3 kg, hospital stay ranging from 16 to 34 weeks, and follow-up ranging from 20 months to 6 years. Postnatal complications in the fetal surgery group included neonatal death (n = 1, secondary to premature closure of ductus arteriosus with cardiac failure), embolic event (n = 1, resulting in unilateral renal agenesis, jejunal atresia), chronic lung disease (n = 1), and tumor recurrence (n = 1).

CONCLUSIONS

For fetal SCT, the rapidity at which cardiac compromise can develop and the high incidence of obstetric complications warrant close prenatal surveillance. Amnioreduction, cyst aspiration, and surgical debulking are potentially life-saving interventions.

Amnioinfusion for meconium-stained liquor in labour

BACKGROUND

Amnioinfusion aims to prevent or relieve umbilical cord compression during labour by infusing a solution into the uterine cavity. It is also thought to dilute meconium when present in the amniotic fluid and so reduce the risk of meconium aspiration. However, it may be that the mechanism of effect is that it corrects oligohydramnios (reduced amniotic fluid), for which thick meconium staining is a marker.

OBJECTIVES

The objective of this review was to assess the effects of amnioinfusion for meconium-stained liquor on perinatal outcome.

SEARCH STRATEGY

The Cochrane Pregnancy and Childbirth Group trials register (October 2001) and the Cochrane Controlled Trials Register (Issue 3, 2001) were searched.

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

Eligibility and trial quality were assessed by one reviewer.

MAIN RESULTS

Twelve studies, most involving small numbers of participants, were included. Under standard perinatal surveillance, amnioinfusion was associated with a reduction in the following: heavy meconium staining of the liquor (relative risk 0.03, 95% confidence interval 0.01 to 0.15); variable fetal heart rate deceleration (relative risk 0.65, 95% confidence interval 0.49 to 0.88); and reduced caesarean section overall (relative risk 0.82, 95% confidence interval 0.69 to 1.97). No perinatal deaths were reported. Under limited perinatal surveillance, amnioinfusion was associated with a reduction in the following: meconium aspiration syndrome (relative risk 0.24, 95% confidence interval 0.12 to 0.48); neonatal hypoxic ischaemic encephalopathy (relative risk 0.07, 95% confidence interval 0.01 to 0.56) and neonatal ventilation or intensive care unit admission (relative risk 0.56, 95% confidence interval 0.39 to 0.79); there was a trend towards reduced perinatal mortality (relative risk 0.34, 95% confidence interval 0.11 to 1.06).

REVIEWER'S CONCLUSIONS

Amnioinfusion is associated with improvements in perinatal outcome, particularly in settings where facilities for perinatal surveillance are limited. 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.

Prophylactic versus therapeutic amnioinfusion for oligohydramnios in labour

BACKGROUND

Amnioinfusion aims to relieve umbilical cord compression during labour by infusing a liquid into the uterine cavity.

OBJECTIVES

The objective of this review was to assess the effects of prophylactic amnioinfusion for oligohydramnios compared with therapeutic amnioinfusion only if fetal heart rate decelerations or thick meconium-staining of the liquor occur.

SEARCH STRATEGY

The Cochrane Pregnancy and Childbirth Group trials register and Cochrane Controlled Trials Register were searched. Date of last search: October 1997.

SELECTION CRITERIA

Randomised trials comparing prophylactic with therapeutic amnioinfusion in women with oligohydramnios but not fetal heart rate deceleration in labour.

DATA COLLECTION AND ANALYSIS

The reviewer assessed trial quality and extracted data.

MAIN RESULTS

Two studies of 285 women were included. No differences were found in the rate of caesarean section (relative risk 0.98, 95% confidence interval 0.58 to 1.66), or forceps delivery. There were no difference in Apgar scores, cord arterial pH, oxytocin augmentation, meconium aspiration, neonatal pneumonia or postpartum endometritis. Prophylactic amnioinfusion was associated with increased intrapartum fever (relative risk 3.48, 95% confidence interval 1.21 to 10.05).

REVIEWER'S CONCLUSIONS

There appears to be no advantage of prophylactic amnioinfusion over therapeutic amnioinfusion carried out only when fetal heart rate decelerations or thick meconium-staining of the liquor occur.

Amnioinfusion for umbilical cord compression in labour

BACKGROUND

Amnioinfusion aims to prevent or relieve umbilical cord compression during labour by infusing a solution into the uterine cavity.

OBJECTIVES

The objective of this review was to assess the effects of amnioinfusion on maternal and perinatal outcome for potential or suspected umbilical cord compression or potential amnionitis.

SEARCH STRATEGY

The Cochrane Pregnancy and Childbirth Group trials register and the Cochrane Controlled Trials Register were searched.

SELECTION CRITERIA

Randomised trials of amnioinfusion compared with no amnioinfusion in women with babies at risk of umbilical cord compression; and women at risk of intrauterine infection.

DATA COLLECTION AND ANALYSIS

Eligibility and trial quality were assessed by the reviewer.

MAIN RESULTS

Twelve studies were included. Transcervical amnioinfusion for potential or suspected umbilical cord compression was associated with the following reductions: fetal heart rate decelerations (relative risk 0.54, 95% confidence interval 0.43 to 0.68); caesarean section for suspected fetal distress (relative risk 0.35, 95% confidence interval 0.24 to 0.52); neonatal hospital stay greater than 3 days (relative risk 0.40, 95% confidence interval 0. 26 to 0.62); maternal hospital stay greater than 3 days (relative risk 0.46, 95% 0.29 to 0.74). Transabdominal amnioinfusion showed similar results. Transcervical amnioinfusion to prevent infection in women with membranes ruptured for more than 6 hours was associated with a reduction in puerperal infection (relative risk 0.50, 95% confidence interval 0.26 to 0.97).

REVIEWER'S CONCLUSIONS

Amnioinfusion appears to reduce the occurrence of variable heart rate decelerations and lower the use of caesarean section. However the studies were done in settings where fetal distress was not confirmed by fetal blood sampling. The results may therefore only be relevant where caesarean sections are commonly done for abnormal fetal heart rate alone. The trials reviewed are too small to address the possibility of rare but serious maternal adverse effects of amnioinfusion.

Maternal hydration for increasing amniotic fluid volume in oligohydramnios and normal amniotic fluid volume

BACKGROUND

Oligohydramnios (reduced amniotic fluid) may be responsible for malpresentation problems, umbilical cord compression, concentration of meconium in the liquor, and difficult or failed external cephalic version. Simple maternal hydration has been suggested as a way of increasing amniotic fluid volume in order to reduce some of these problems.

OBJECTIVES

The objective of this review was to assess the effects of maternal hydration on amniotic fluid volume and measures of pregnancy outcome.

SEARCH STRATEGY

The Cochrane Pregnancy and Childbirth Group trials register and the Cochrane Controlled Trials Register were searched. Date of last search: 1 February 1999.

SELECTION CRITERIA

Randomised trials comparing maternal hydration with no hydration in pregnant women with reduced or normal amniotic fluid volume.

DATA COLLECTION AND ANALYSIS

Eligibility and trial quality were assessed by both reviewers.

MAIN RESULTS

Two studies of 77 women were included. The women were asked to drink two litres of water before having a repeat ultrasound examination. Maternal hydration in women with and without oligohydramnios was associated with an increase in amniotic volume (weighted mean difference for women with oligohydramnios 2.01, 95% confidence interval 1.43 to 2.56; and weighted mean difference for women with normal amniotic fluid volume 4.5, 95% confidence interval 2.92 to 6.08). Intravenous hypotonic hydration in women with oligohydramnios was associated with an increase in amniotic fluid volume (weighted mean difference 2.3, 95% confidence interval 1.36 to 3.24). Isotonic intravenous hydration had no measurable effect. No clinically important outcomes were assessed in any of the trials.

REVIEWER'S CONCLUSIONS

Simple maternal hydration appears to increase amniotic fluid volume and may be beneficial in the management of oligohydramnios and prevention of oligohydramnios during labour or prior to external cephalic version. Controlled trials are needed to assess the clinical benefits and possible risks of maternal hydration for specific clinical purposes.

Amnioinfusion for preterm rupture of membranes

BACKGROUND

Preterm rupture of membranes places a fetus at risk of cord compression and amnionitis. Amnioinfusion aims to prevent or relieve umbilical cord compression by infusing a solution into the uterine cavity.

OBJECTIVES

The objective of this review was to assess the effects of amnioinfusion for preterm rupture of membranes on maternal and perinatal outcomes.

SEARCH STRATEGY

The Cochrane Pregnancy and Childbirth Group trials register and the Cochrane Controlled Trials Register were searched.

SELECTION CRITERIA

Randomised trials of amnioinfusion compared to no amnioinfusion in women with preterm rupture of membranes.

DATA COLLECTION AND ANALYSIS

Eligibility and trial quality were assessed by the reviewer.

MAIN RESULTS

One trial of 66 women was included. It had some methodological flaws. No significant differences between amnioinfusion and no amnioinfusion were detected for caesarean section (relative risk 0.32, 95% confidence interval 0.07 to 1.40); low Apgar scores (relative risk 0.28, 95% confidence interval 0.03 to 2.33) or neonatal death (relative risk 0.55, 95% confidence interval 0.05 to 5.77). In the amnioinfusion group, the number of severe fetal heart rate decelerations per hour during the first stage of labour were reduced (weighted mean difference -1.20, 95% confidence interval -1.83 to -0.57). These outcomes are consistent with those found in the Cochrane review on amnioinfusion for cord compression.

REVIEWER'S CONCLUSIONS

There is not enough evidence concerning the use of amnioinfusion for preterm rupture of membranes.

The Collaborative Randomised Amnioinfusion for Meconium Project (CRAMP): 1. South Africa

OBJECTIVE

To evaluate transcervical amnioinfusion for meconium stained amniotic fluid during labout.

DESIGN

Multicentre randomised controlled trial.

SETTING

Four urban academic hospitals in South Africa. Obstetric surveillance included the use of electronic fetal heart rate monitoring in most cases.

PARTICIPANTS

Women in labour at term with moderate or thick meconium staining of the amniotic fluid.

INTERVENTIONS

Transcervical amnioinfusion of 800 mL saline at 15 mL per minute, followed by a maintenance infusion at 3 mL per minute. The control group received routine care. Blinding of the intervention was not possible.

MAIN OUTCOME MEASURES

Caesarean section, meconium aspiration syndrome and perinatal mortality.

RESULTS

Caesarean section rates were similar (amnioinfusion group 70/167 vs control group 68/159; RR 0.98, 95% CI 0.76-1.26). The incidence of meconium aspiration syndrome was lower than expected on the basis of previous studies (4/162 vs 6/163; RR 0.67, 95% CI 0.19-2.33). There were no perinatal deaths. There were no significant differences between any of the subsidiary outcomes.

CONCLUSIONS

This study concurred with three previous trials which found no effect of amnioinfusion for meconium-stained amniotic fluid on caesarean section rate, though the pooled data from all identified trials to date show a significant reduction. The findings with respect to meconium aspiration syndrome were inconclusive in this study alone because of the small number of babies affected, but the point estimate of the relative risk was consistent with the finding of a significant reduction in previous studies and with the Zimbabwe arm (CRAMP 2) of this study. Pooled data clearly support the use of amnioinfusion for meconium stained amniotic fluid to reduce the incidence of meconium aspiration syndrome.