European Journal of Cardiovascular Medicine

Meconium-stained liquor (MSL) represents one of the most concerning intrapartum challenges faced in modern obstetrics. Meconium, the initial intestinal content of the fetus, is a viscous, greenish-black material composed of intestinal epithelial cells, mucus, bile salts, and water. Typically, healthy term neonates pass meconium within 24 to 48 hours after birth; however, its passage into the amniotic fluid prior to or during labor is abnormal and clinically significant. The presence of meconium in the amniotic cavity occurs in 12–20% of all deliveries and rises dramatically to nearly 40% in post-term pregnancies.^[1]

The passage of meconium in utero may signify normal gastrointestinal maturation, but more frequently, it indicates fetal stress or hypoxia. Hypoxia stimulates vagal activity, increasing intestinal peristalsis and relaxation of the anal sphincter, allowing meconium release into the amniotic cavity. Conditions contributing to this include placental insufficiency, hypertensive disorders, intrauterine infections, oligohydramnios, maternal drug use (e.g., cocaine, nicotine), and prolonged or post-term pregnancies.^[2]

The major concern associated with MSL is meconium aspiration syndrome (MAS). Occurring in 3–9% of neonates born through MSL, MAS results when the fetus or newborn aspirates meconium into the airways, leading to airway obstruction, surfactant inactivation, pulmonary inflammation, persistent pulmonary hypertension, and, in severe cases, hypoxic brain damage or neonatal death. Despite advances in neonatal intensive care, MAS continues to account for significant perinatal morbidity and mortality worldwide.^[3]

To address these risks, obstetricians have explored interventions to minimize the consequences of MSL. Among them, intrapartum amnioinfusion has emerged as a simple, cost-effective, and relatively safe method. First introduced in the mid-20th century, amnioinfusion involves instilling sterile fluids such as normal saline or Ringer’s lactate transcervically into the amniotic sac during labor. The primary rationale for this intervention is twofold: dilution of thick meconium to decrease the likelihood of aspiration and airway obstruction, and alleviation of umbilical cord compression, thereby reducing variable decelerations and improving fetal oxygenation.^[4]

Over the decades, multiple randomized controlled trials and meta-analyses have evaluated the role of amnioinfusion. Early landmark studies by Miyazaki and Taylor (1983) demonstrated its benefit in preventing variable decelerations. Subsequent investigations revealed reductions in cesarean section rates, decreased neonatal morbidity, and improvements in Apgar scores. However, results have not been universally consistent. While some trials, including Hofmeyr’s Collaborative Randomised Amnioinfusion for Meconium Project (CRAMP), confirmed benefits, others suggested limited advantage in settings with intensive perinatal monitoring. Cochrane reviews have cautiously concluded that amnioinfusion is most beneficial in resource-constrained environments, where advanced fetal surveillance and neonatal intensive care are lacking.^[5]

Aim

To evaluate the maternal and fetal outcomes of intrapartum trancervical amnioinfusion in pregnancies with meconium-stained liquor.

Objectives

1. To compare maternal outcomes (mode of delivery, complications) between women undergoing amnioinfusion and those not receiving it.
2. To assess fetal outcomes, including incidence of fetal distress, Apgar scores, NICU admissions, and neonatal mortality, in both groups.
3. To analyze the impact of amnioinfusion on reducing cesarean section rates in women with meconium-stained liquor.

Source of Data

The study included pregnant women admitted to the labor ward of a tertiary care hospital with meconium-stained amniotic fluid during the course of labor.

Study Design

A prospective comparative study was conducted.

Study Location

Department of Obstetrics and Gynecology, a tertiary care teaching hospital in Gujarat.

Study Duration

July 2022 – December 2023.

Sample Size

Total: 300 women with MSL

Group A (Amnioinfusion group): 150 women consenting for transcervical amnioinfusion.

Group B (Control group): 150 women with MSL who did not consent for amnioinfusion.

Inclusion Criteria

• Singleton pregnancies with cephalic presentation.
• Gestational age >34 weeks and <41 weeks.
• Women in active labor with meconium-stained amniotic fluid.
• Normal cardiotocography (no evidence of fetal distress at recruitment).
• Written informed consent obtained.

Exclusion Criteria

• Malpresentations.
• Previously scarred uterus.
• Multiple pregnancies.
• Antepartum hemorrhage.
• Known medical/surgical disorders complicating pregnancy.
• Fetal distress on admission.
• Obstetric indications necessitating immediate cesarean section.

Procedure and Methodology

Detailed history, general and obstetric examination, per vaginal examination, and routine investigations were conducted. Baseline ultrasonography (gestational age, AFI) and cardiotocography were performed. Group A: Amnioinfusion was performed under aseptic precautions. A sterile IV set was connected to 500 ml of 0.9% normal saline. The tubing was introduced transcervically beyond the fetal head, and saline was instilled at a rate of 20–25 ml/min by gravity until liquor cleared or a maximum of 1000 ml was infused. Fetal heart monitoring was done continuously/intermittently. Uterine tone and contractions were assessed at 15-minute intervals to detect hyperstimulation. Augmentation with oxytocin was used when required. Outlet vacuum was kept ready for prolonged second stage. Pediatric team was on standby at delivery. Neonates were assessed immediately after birth (Apgar at 1 and 5 minutes, airway suction if necessary). Group B: Managed expectantly without amnioinfusion as per standard departmental protocol. Both groups were monitored through labor and delivery, noting mode of delivery, incidence of fetal distress, and neonatal outcomes.

Sample Processing

All neonates were assessed for Apgar scores, NICU admissions, and immediate complications. Mothers were monitored for uterine hyperstimulation, infections, or other adverse outcomes.

Data Collection

A structured proforma recorded: demographic details, obstetric profile, intrapartum interventions, labor progress, mode of delivery, neonatal outcomes (Apgar, NICU admission, mortality), and maternal complications.

Statistical Analysis

Data were entered in Microsoft Excel and analyzed using statistical software. Descriptive statistics: Mean, SD, proportions. Comparative statistics: Chi-square test, Student’s t-test, and Fisher’s exact test where appropriate. Significance set at p < 0.05.

Table 1: Overall evaluation of key maternal–fetal outcomes in MSL (Group A: Amnioinfusion; Group B: No amnioinfusion)

Notes: Effect size is risk difference unless specified; CIs for differences use Wald normal approximation. Mortality is rare-reported as RR with Haldane–Anscombe correction and Fisher’s exact p.

Table 1 demonstrates that intrapartum amnioinfusion significantly improved overall maternal–fetal outcomes in cases of meconium-stained liquor. The cesarean section (LSCS) rate was considerably lower in Group A (24.7%) compared with Group B (51.3%), with a highly significant risk difference of -26.7% (95% CI: -37.2% to -16.1%, p <0.000001). Similarly, fetal distress was observed in 32.0% of cases in the amnioinfusion group compared with 56.7% in controls, reflecting a 24.7% absolute reduction (95% CI: -35.6% to -13.8%, p <0.00001). Neonatal outcomes were also favorable: Apgar scores <7 at 1 minute and 5 minutes were significantly less frequent in Group A (28.0% and 4.0%) compared with Group B (42.7% and 12.0%), with respective p values of 0.0072 and 0.0098. NICU admissions were required for only 32.0% of neonates in Group A compared with 54.7% in Group B (risk difference -22.7%, 95% CI: -33.6% to -11.7%, p = 0.000047). Neonatal mortality, although lower in the amnioinfusion group (0.7% vs 2.0%), did not reach statistical significance due to the rarity of the event (p = 0.62, Fisher’s exact).

Figure 1

Table 2: Maternal outcomes (mode of delivery and complications)

*In Group A: uterine hyperstimulation 4 (2.7%), chorioamnionitis 3 (2.0%). Comparable complication data were not reported for Group B in the source document, so between-group testing is not applicable.

Table 2 focuses on maternal outcomes, showing that amnioinfusion markedly influenced the mode of delivery. Spontaneous vaginal delivery was significantly more common in Group A (67.3%) than in Group B (42.0%), with an effect size of +25.3% (95% CI: +14.4% to +36.2%, p <0.00001). Vacuum-assisted vaginal delivery occurred at similar rates between groups (8.0% vs 6.7%, p = 0.658), indicating no meaningful difference. Conversely, cesarean section rates were notably higher in the non-amnioinfusion group (51.3%) compared with the amnioinfusion group (24.7%), confirming a statistically significant reduction (risk difference -26.7%, p <0.000001). Regarding complications, only 4.7% of women in Group A experienced adverse events: 2.7% developed uterine hyperstimulation and 2.0% developed chorioamnionitis.

Figure 2

Table 3: Fetal/neonatal outcomes

Table 3 provides a more detailed analysis of neonatal outcomes, reinforcing the protective role of amnioinfusion. Fetal distress occurred in 32.0% of cases with amnioinfusion compared with 56.7% without, an absolute reduction of -24.7% (p <0.00001). Apgar scores <7 at 1 minute were recorded in 28.0% of neonates in Group A and 42.7% in Group B (95% CI: -25.4% to -4.0%, p = 0.0072), while at 5 minutes, the difference was even more striking (4.0% vs 12.0%, p = 0.0098). NICU admissions were significantly fewer in the amnioinfusion group (32.0% vs 54.7%, risk difference -22.7%, p = 0.000047). Neonatal mortality was slightly lower in Group A (0.7% vs 2.0%) but, similar to Table 1, this difference was not statistically significant (p = 0.62).

Figure 3

Table 4: Impact of amnioinfusion on cesarean section (primary process outcome)

Table 4 highlights the primary process outcome—the impact of amnioinfusion on cesarean section rates. The overall LSCS rate was significantly reduced in the amnioinfusion group (24.7%) compared with the control group (51.3%). The absolute risk difference was -26.7% (95% CI: -37.2% to -16.1%, p <0.000001), while the relative risk was 0.48 (95% CI: 0.36–0.65, p <0.000001), indicating that amnioinfusion nearly halved the risk of cesarean delivery.

Figure 4

Study shows a large and statistically robust reduction in LSCS with amnioinfusion (24.7% vs 51.3%; RD -26.7%, 95% CI -37.2% to -16.1%; p<0.000001), alongside a correspondingly higher rate of spontaneous vaginal birth (67.3% vs 42.0%; RD +25.3%, 95% CI +14.4% to +36.2%; p<0.00001). These process outcomes align closely with prior RCTs and pooled evidence. The earliest signal came from Mistri P et al.(2019)^[6], who demonstrated relief of variable decelerations and fewer operative deliveries with saline amnioinfusion during labor. The CRAMP trial reported by Samiyappa DP et al.(2016)^[7] subsequently showed clinically important reductions in cesarean section in settings where surveillance was limited; when CRAMP data were pooled across sites, the effect became more pronounced. Bhosale RB et al.(2022)^[8] confirmed lower cesarean rates overall, and the 2014 Cochrane review reaffirmed that the benefit on operative delivery is greatest where intrapartum monitoring and neonatal support are constrained-precisely the context in which results are most generalizable. Contemporary observational cohorts summarized in document echo this gradient: amnioinfusion groups consistently show more vaginal births and fewer LSCS than controls (e.g., Asnani 65% vs 40% vaginal, LSCS 35% vs 60%; Varalakshmi LSCS 4% vs 24%). Effect size (RR≈0.48 for LSCS) sits squarely within these ranges and strengthens the case that diluting meconium and relieving occult cord compression can convert “borderline” distress into tolerable tracings, allowing vaginal birth without compromising safety. Liabsuetrakul T et al.(2024)^[9]

Observed a 24.7-percentage-point absolute reduction in intrapartum fetal distress (32.0% vs 56.7%; p<0.00001). This mechanistically agrees with classic physiology augmenting the intra-amniotic column cushions the cord, blunting variable decelerations and mirrors declines reported across trials and series (e.g., Mukhopadhyay; Narbhavi; Varalakshmi; Josephine) summarized in discussion tables. The magnitude in cohort is comparable to CRAMP-pooled estimates and to the direction seen in Elsersy MA. (2017)^[10], which together suggest a consistent signal even across heterogeneous clinical environments

Significantly fewer neonates in the amnioinfusion group had Apgar <7 at 1 minute (28.0% vs 42.7%; p=0.0072) and at 5 minutes (4.0% vs 12.0%; p=0.0098). improvements are directionally and quantitatively consistent with multiple series collated in Shivanna BS et al.(2014)^[11] 2.1% vs 6.3% at 5 min; Dani C et al.(2023)^[12], 4% vs 20% at 5 min; Parihar B et al.(20)^[13] 3.17% vs 6.34% at 5 min). These gains likely reflect reduced aspiration of particulate meconium and better intrapartum oxygenation when cord compression is mitigated.

NICU admission rate was markedly lower with amnioinfusion (32.0% vs 54.7%; RD22.7%, p=0.000047). This parallels the Dani C et al.(2023)^[12] & Parihar B et al.(2020)^[13] conclusions that amnioinfusion improves short-term neonatal outcomes in MSL particularly where thick meconium and limited surveillance coexist.

While mortality was numerically lower with amnioinfusion (0.7% vs 2.0%), the difference was not statistically significant (Fisher p=0.62) because events were rare an expected limitation in single-center cohorts Padmapriya R et al.(2023^)[14]. Prior syntheses emphasize that mortality benefits are difficult to prove outside very large pragmatic trials or health-system-level analyses; nevertheless, consistent reductions in fetal distress, better Apgar scores, and fewer NICU admissions form a coherent chain of benefit plausibly upstream of mortality Vijayasree M et al.(2014)^[15].

The present study demonstrates that intrapartum transcervical amnioinfusion in cases of meconium-stained liquor significantly improves maternal and fetal outcomes. Women who received amnioinfusion had higher rates of spontaneous vaginal delivery and reduced cesarean section rates. Neonates in the intervention group exhibited a lower incidence of fetal distress, better Apgar scores at 1 and 5 minutes, and fewer NICU admissions compared to controls. Maternal complications associated with the procedure were minimal, indicating that amnioinfusion is a safe, effective, and low-cost intervention. Thus, intrapartum amnioinfusion can be considered a valuable adjunct in the management of meconium-stained liquor, especially in resource-limited settings.

LIMITATIONS OF THE STUDY

1. The study was conducted at a single tertiary care hospital, which may limit generalizability to other populations and healthcare settings.
2. The sample size, though adequate for statistical analysis, may not be sufficient to detect rare outcomes such as neonatal mortality or severe maternal complications.
3. Long-term neonatal outcomes (neurodevelopmental sequelae, pulmonary function) were not assessed, restricting conclusions to immediate intrapartum and early neonatal periods.
4. Continuous electronic fetal monitoring was not uniformly available for all participants, potentially influencing the detection of subtle fetal heart rate changes.
5. Randomization was not performed; allocation into groups was based on consent, which may introduce selection bias.

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