The frequency of meconium-stained amniotic fluid increases as a function of the duration of labor

Meconium-stained amniotic fluid and neonatal morbidity in nulliparous patients with prolonged pregnancy

INTRODUCTION

Our objective was to study the strength of the association between meconium-stained amniotic fluid and severe morbidity among neonates of nulliparas with prolonged pregnancies.

MATERIAL AND METHODS

This was a secondary analysis of the NOCETER randomized trial that took place between 2009 and 2012 in which 11 French maternity units included 1373 nulliparas at 41⁺⁰  weeks of gestation onwards with a single live fetus in cephalic presentation. This analysis excluded patients with a cesarean delivery before labor and those with bloody amniotic fluid or of unreported consistency. The principal end point was a composite criterion of severe neonatal morbidity (neonatal death, 5-minute Apgar <7, convulsions in the first 24 h, meconium aspiration syndrome, mechanical ventilation ≥24 h, or neonatal intensive care unit admission for 5 days or more). The neonatal outcomes of pregnancies with thin or thick meconium-stained amniotic fluid were compared with those with normal amniotic fluid. The association between the consistency of the amniotic fluid and neonatal morbidity was tested by univariate and then multivariate analysis adjusted for gestational age at birth, duration of labor, and country of birth.

RESULTS

This study included 1274 patients: 803 (63%) in the group with normal amniotic fluid, 196 (15.4%) in the thin amniotic fluid group, and 275 (21.6%) in the thick amniotic fluid group. The neonates of patients with thick amniotic fluid had higher rates of neonatal morbidity than those of patients with normal amniotic fluid (7.3% vs. 2.2%; p < 0.001; adjusted relative risk [aRR] 3.3, 95% confidence interval [CI] 1.7-6.3), but those of patients with thin amniotic fluid did not (3.1% vs. 2.2%; p = 0.50; aRR 1.0, 95% CI, 0.4-2.7).

CONCLUSIONS

Among nulliparas at 41⁺⁰  weeks onwards, only thick meconium-stained amniotic fluid is associated with a higher rate of severe neonatal morbidity.

Meconium-stained amniotic fluid

Green-stained amniotic fluid, often referred to as meconium-stained amniotic fluid, is present in 5% to 20% of patients in labor and is considered an obstetric hazard. The condition has been attributed to the passage of fetal colonic content (meconium), intraamniotic bleeding with the presence of heme catabolic products, or both. The frequency of green-stained amniotic fluid increases as a function of gestational age, reaching approximately 27% in post-term gestation. Green-stained amniotic fluid during labor has been associated with fetal acidemia (umbilical artery pH <7.00), neonatal respiratory distress, and seizures as well as cerebral palsy. Hypoxia is widely considered a mechanism responsible for fetal defecation and meconium-stained amniotic fluid; however, most fetuses with meconium-stained amniotic fluid do not have fetal acidemia. Intraamniotic infection/inflammation has emerged as an important factor in meconium-stained amniotic fluid in term and preterm gestations, as patients with these conditions have a higher rate of clinical chorioamnionitis and neonatal sepsis. The precise mechanisms linking intraamniotic inflammation to green-stained amniotic fluid have not been determined, but the effects of oxidative stress in heme catabolism have been implicated. Two randomized clinical trials suggest that antibiotic administration decreases the rate of clinical chorioamnionitis in patients with meconium-stained amniotic fluid. A serious complication of meconium-stained amniotic fluid is meconium aspiration syndrome. This condition develops in 5% of cases presenting with meconium-stained amniotic fluid and is a severe complication typical of term newborns. Meconium aspiration syndrome is attributed to the mechanical and chemical effects of aspirated meconium coupled with local and systemic fetal inflammation. Routine naso/oropharyngeal suctioning and tracheal intubation in cases of meconium-stained amniotic fluid have not been shown to be beneficial and are no longer recommended in obstetrical practice. A systematic review of randomized controlled trials suggested that amnioinfusion may decrease the rate of meconium aspiration syndrome. Histologic examination of the fetal membranes for meconium has been invoked in medical legal litigation to time the occurrence of fetal injury. However, inferences have been largely based on the results of in vitro experiments, and extrapolation of such findings to the clinical setting warrants caution. Fetal defecation throughout gestation appears to be a physiologic phenomenon based on ultrasound as well as in observations in animals.

Exposure to Meconium-Stained Amniotic Fluid and Long-Term Neurological-Related Hospitalizations throughout Childhood

OBJECTIVE

This study aimed to investigate the possible impact of meconium-stained amniotic fluid (MSAF) on the occurrence of neurological-related hospitalizations throughout childhood and adolescence.

STUDY DESIGN

In this population-based cohort analysis, all singleton deliveries occurring between 1991 and 2014 at the Soroka University Medical center were included and the long-term neurological-related hospitalizations were compared between children with and without MSAF during their delivery. A Kaplan-Meier survival analysis was constructed for the evaluation of cumulative hospitalization rate due to neurological morbidity over the 18 years of follow-up, and a Cox proportional hazards model was used to study the independent association between MSAF and childhood neurological morbidity while controlling for potential confounders.

RESULTS

During the study period, 243,725 deliveries met the inclusion criteria; 35,897 of the cohort (15%) constituted the exposed group (MSAF), while the rest of the cohort (n = 207,828) constituted the unexposed group (no MSAF). A total of 7,543 hospitalizations due to neurological-related morbidity were documented with a rate of 3.2% (1,152) in children exposed to MSAF as compared with 3.1% (6,391) in the unexposed group (OR 1.1, 95% confidence interval 0.9-1.1, p = 0.149). The survival curve showed a comparable cumulative hospitalization rate in the MSAF-exposed group compared with the unexposed group (log rank p = 0.349). The Cox analysis, controlled for gestational diabetes and hypertension, gestational and maternal ages, demonstrated MSAF exposure not to be an independent risk factor for neurological-related hospitalizations during childhood (adjusted hazard ratio = 1.03, 0.96-1.09).

CONCLUSION

Fetal exposure to MSAF, at any gestational age, does not appear to be an independent risk factor for later neurological-related hospitalizations throughout childhood and adolescence.

KEY POINTS

· MSAF is associated with several short-term complications such as low Apgar scores.. · The long-term implications of MSAF exposure are yet to be clearly defined.. · Fetal exposure to MSAF is not a risk factor for neurological morbidity throughout childhood..

Newborn-oriented and environmental factors for newborns' skin barrier functions

AIM

This study aimed to examine newborn-oriented and environmental factors of newborn skin barrier functions.

METHODS

This was a retrospective secondary analysis of 227 newborns from a previous study. Newborn skin barrier functions were measured on the fourth day after birth via the following parameters: stratum corneum hydration, transepidermal water loss, skin pH, and sebum secretion. Skin barrier functions were measured at four body sites; their averaged values were used for the analysis. The associations among skin barrier functions, newborn-oriented factors, and environmental factors were evaluated. Multiple regression analysis was performed using a forced entry method, and independent variables for which p-values were <.05 in Student's t test, analysis of variance, and Pearson's correlation analysis were included.

RESULTS

A total of 211 participants were analyzed. The mean ± standard deviation values of stratum corneum hydration, transepidermal water loss, skin pH, and sebum secretion were 28.58 ± 8.40 and 7.28 ± 2.02 g/m² /h, 5.77 ± 0.53, and 23.59 ± 15.89 μg/cm² , respectively. Newborn-oriented factors (gestational days, weight, amount of vernix, and parity) and environmental factors (birth season) were significantly associated with one or more skin barrier functions.

CONCLUSIONS

Newborn-oriented (including labor- and delivery-related) and environmental factors were associated with the skin barrier functions. The newborn maturity level, newborn sex, environmental temperature, and humidity may affect skin barrier functions in newborns. Further studies should focus on the effects of these factors on newborn skin barrier assessments, and develop tailored skincare strategies based on their characteristics.

Prevalence and Factors Associated with Meconium-Stained Amniotic Fluid in a Tertiary Hospital, Northwest Ethiopia: A Cross-Sectional Study

Background. Fetal bowel could pass meconium, a green viscous fluid, before or during labour and most intrauterine passage of meconium is associated with several fetomaternal factors that lead to increased risk of perinatal morbidity and mortality. Given that there is a paucity of data, this study was conducted to assess the proportion and associated factors of meconium-stained amniotic fluid (MSAF) in women who came for labour and delivery service in a tertiary hospital. Methods. A cross-sectional study was conducted from 1 June to 31 August 2018 among 606 labouring mothers at Felege Hiwot Referral Hospital, northwest Ethiopia. Study participants were selected using a systematic random sampling technique. Data were collected using an interviewer-administered pretested questionnaire and data checklist. Factors associated with MSAF were explored using multivariable logistic regression analysis. Results. MSAF occurred in 24.6% (149/606) of pregnancies. Nonreassuring fetal heart rate patterns (Adjusted Odds Ratio [AOR]: 21.9, 95% Confidence interval [95% CI]: 10.96–43.83), postterm pregnancy (AOR: 4.54, 95% CI: 2.24–9.20), duration of labour more than 15 hours (AOR: 2.83, 95% CI: 1.76–4.53), pregnancy-induced hypertension (AOR: 2.43, 95% CI: 1.45–4.05), oligohydramnios (AOR: 2.53, 95% CI: 1.25–5.12), interpregnancy interval less than 2 years (AOR: 2.24, 95% CI: 1.12–4.51), and monthly family income less than 5000 Ethiopian Birr (185 USD) (AOR: 2.03, 95% CI: 1.18–3.51) were significantly associated with MSAF. Conclusions. In this study, the proportion of MSAF was at 24.6% which was higher than a previous report in Ethiopia. Nonreassuring fetal heart rate pattern, postterm pregnancy, duration of labour more than 15 hours, pregnancy-induced hypertension, oligohydramnios, interpregnancy interval less than 2 years, and monthly family income less than 5000 Ethiopian Birr were factors associated with an increased risk for MSAF. Therefore, interventions aimed at detecting MSAF early should consider these factors.

Prolonged exposure to meconium in cases of spontaneous premature rupture of membranes at term and pregnancy outcome

OBJECTIVE

To evaluate the impact of prolonged exposure to meconium-stained amniotic fluid (MSAF), in women with term pre-labor spontaneous rupture of membranes (PROM), on pregnancy outcome.

METHODS

A retrospective cohort study of women who gave birth in a single university-affiliated tertiary medical center (2011-2019). Eligibility was limited to singleton pregnancies at term who presented with PROM. Women with MSAF were immediately induced and were compared to low-risk pregnant women with clear amniotic fluid (CAF) at admission who underwent induction of labor 24 h after rupture of membranes. All women were stratified into 4-time frame groups from rupture of membranes to delivery: T0: 0-7 h, T1: 8-13 h, T2: 14-18 h, and T3: > 18 h for the MSAF group. The time frames for the CAF were: T0 - 24-31 h, T1: 32-38 h, T2: 40-44 h, and T3: > 44 h. The maternal adverse composite outcome included any of the following: intrapartum fever (IPF), prolonged second stage (PSS), need for manual removal of suspected retained placenta, postpartum hemorrhage, and readmission within 45 days after delivery. The adverse composite neonatal outcome included one or more of the following: meconium aspiration syndrome, neonatal asphyxia, need for respiratory support, and intracranial hemorrhage.

RESULTS

Overall, 1631 women met the inclusion criteria (536 in the MSAF and 1095 in the CAF group). Both groups showed a gradual decrease in the rate of vaginal delivery over time, the vaginal delivery rate in the MSAF group was 75.7% at T0 in comparison to 61.6% at T3 (p < .001). In the CAF group, the vaginal delivery rate was 84.5% at T0 in comparison to 68.8% at T3 (p < .001). This decrease was in concomitance with an increase in the rates of prolonged second-stage and intrapartum fever. There were no significant differences in the rates of postpartum hemorrhage, suspected retained placenta, or readmission within 45 days between women with either MSAF or CAF. There was a significant gradual increase in the adverse composite neonatal outcome in the MSAF group (1.9% at T0, 5.2% at T1, 6.0% at T2, and 8.2% at T3. p = .038). No similar increase was found in the CAF group (2.5% at T0, 4.1% at T1, 2.6% at T2, and 4.1% at T3. p = .449).

CONCLUSION

Prolonged rupture of membranes in the presence of meconium does not affect maternal outcomes, however, prolonged exposure to meconium lead to an increased adverse neonatal outcome.

Association of Apgar Score With Meconium Staining of Amniotic Fluid in Labor

Objective

This study aimed to determine the association of Apgar score with meconium staining of amniotic fluid in labor.

Methodology

A retrospective observational study was carried out through the non-probability convenient sampling technique at the Department of Obstetrics and Gynecology for a duration of six months. Only those women were selected who had more than 24 weeks of gestation period. The women were excluded on the basis of risk factors for fetal distress and breech in late labor.

Results

A total of 216 pregnant women were selected from the labor room in this study. The mean age of the women was 26.57±4.28 years. The gestational age of the women was 36.09±4.11 weeks. Moreover, the mean parity of pregnant women was 1.68±2.53. It has been observed that the women who had meconium staining, the neonates of 144(77.4%) women showed the Apgar score of less than six at one minute. However, for the women without meconium staining, the neonates of only 15(50%) women showed the Apgar score of less than six at the one-minute interval with a significant association (p=0.02). With respect to age groups, a significant association of meconium staining with Apgar score was noted in the 21-30 years age group, whereas, no significant association was seen in other age groups. Similarly, a significant association of meconium staining and Apgar score was noted in primiparous women, whereas, no significant association was noted in multiparous women. No significant association of Apgar score and meconium staining was seen with respect to the mode of delivery.

Conclusion

The study has found a relation between the Apgar score and meconium staining of amniotic fluid and reported that the Apgar score of less than six at one minute was significantly associated with meconium staining of amniotic fluid.

Prediction of adverse neonatal outcome among newborns born through meconium-stained amniotic fluid

OBJECTIVE

To study maternal and intrapartum factors associated with adverse neonatal outcome in deliveries complicated by meconium-stained amniotic fluid (MSAF).

METHODS

A retrospective cohort study of all women with singleton gestations undergoing trial of labor with MSAF during 2011-2020. Deliveries with adverse neonatal outcome were compared with deliveries without.

RESULTS

Overall, 11 329 were included; 376 (3.3%) neonates were diagnosed with adverse neonatal outcomes. Multivariable regression analysis underlined the following factors as independently associated with composite adverse neonatal outcome: pregestational diabetes (odds ratio [OR] 3.21, 95% confidence interval [CI] 1.09-9.43, P = 0.031), polyhydramnios (OR 2.14, 95% CI 1.33-3.44, P = 0.002), fever (OR 2.52, 95% CI 1.67-3.80, P < 0.001), and amnioinfusion (OR 1.73, 95% CI 1.24-2.2438, P = 0.003). When 0, 1, 2, and 3 of the independent risk factors identified were present, the rates of adverse neonatal outcome were 2.9%, 5.5%, 10.0%, and 100%, respectively.

CONCLUSION

The current study's results suggest that special attention should be payed to deliveries complicated by MSAF and with any of the following factors-polyhydramnios, intrapartum fever, amnioinfusion, and pregestational diabetes.

Early Preterm meconium stained amniotic fluid is an independent risk factor for peripartum maternal bacteremia

OBJECTIVE

To investigate the association of maternal peripartum bacteremia and meconium stained amniotic fluid in early preterm deliveries.

METHODS

We conducted a single center retrospective study, in a tertiary university affiliated medical center. The study cohort included women with culture proven maternal bacteremia who had a preterm delivery between 24-34 weeks of gestation. The control group composed of women with similar gestational age at delivery without bacteremia. Maternal characteristics were compared between the groups.

RESULTS

During the six-years study period there were 86,590 deliveries in our center. 2625 (3.03 %) women had early preterm deliveries (24-34 weeks), of them 22 (0.84 %) were diagnosed with peripartum bacteremia. The groups were similar with regard to obstetric and demographic characteristics. In the peripartum maternal bacteremia group, we found significantly higher rates of MSAF (6.86 % vs 22.73 %, p = 0.036). Logistic regression of multivariable analysis demonstrated that MSAF is an independent risk factor for maternal bacteremia adjusted for gestational age, intrapartum fever and leukocytosis (Odd Ratio 4.29, 95 % CI 1.26-12.56, p = 0.012) CONCLUSION: Preterm MSAF is an independent risk factor for maternal bacteremia among women with early preterm delivery. More studies are needed to determine the need for broad spectrum antibiotic prophylaxis therapy in preterm deliveries complicated by MSAF.

The effect of meconium-stained amniotic fluid on perinatal outcome in pregnancies complicated by preterm premature rupture of membranes

PURPOSE

To determine whether meconium-stained amniotic fluid (MSAF) encountered in pregnancies complicated by preterm premature rupture of membranes (PPROM) is associated with adverse maternal and perinatal outcome.

METHODS

A retrospective cohort study of all singleton pregnancies with PPROM and MSAF who delivered in a tertiary hospital at 24 + 0-36 + 6 weeks of gestation between 2007 and 2017. Women with PPROM-MSAF (study group) were compared to women with PPROM and clear amniotic fluid (control group). Controls were matched to cases according to age, gravidity, parity and gestational age at delivery in a 3:1 ratio. Primary outcome was defined as neonatal intensive care unit admission. Secondary outcomes were neonatal adverse outcomes, chorioamnionitis and placental abruption diagnosed clinically or by placental cultures and histology.

RESULTS

Seventy-five women comprised the study group and were matched to 225 women representing the control group. A significantly higher rate of neonatal intensive care unit admissions was noted in the study group compared to controls (61.3% vs. 45.7%, p = 0.03). Multivariate analysis demonstrated that MSAF is an independent risk factor for neonatal intensive care unit admission (adjusted OR = 2.82, 95% CI 1.39-5.75, p = 0.004). MSAF was found to be associated to higher rates of cesarean and operative vaginal deliveries (30.7% vs. 24.4% and 5.3% vs. 2.7%, p = 0.057, respectively) as well as to chorioamnionitis and placental abruption (33.3% vs. 19.3%, p = 0.034 and 16.0% vs. 7.7%, p = 0.021, respectively).

CONCLUSION

MSAF is associated with higher frequencies of adverse perinatal outcome when compared to clear amniotic fluid in pregnancies complicated by PPROM.

Meconium aspiration syndrome: incidence, associated risk factors and outcome-evidence from a multicentric study in low-resource settings in Nepal

AIM

The aim of this study was to identify the incidence, risk factors and outcome associated with meconium aspiration syndrome (MAS).

METHODS

An observational study was conducted in 12 public hospitals in Nepal from 1 July 2017 to 29 August 2018. All babies born within the study period were included in the study. Babies who were diagnosed as MAS were designated as outcome. Data were analysed with bivariate analysis followed by multiple regression analysis.

RESULTS

The overall incidence of MAS was 2.0 per 1000 livebirths. Babies born at post-term gestation (adjusted odds ratio (AOR) = 2.41; 95% confidence interval (CI): 1.05-5.55), nulliparity (AOR = 2.26; 95% CI: 1.20-4.28), instrumental delivery (AOR = 4.79; 95% CI: 2.52-9.10) and caesarean delivery (AOR = 3.67; 95% CI: 2.29-5.89) were significantly associated with MAS. Babies with MAS had a 10-fold risk for pre-discharge mortality (odds ratio = 9.87; 95% CI: 5.81-16.76).

CONCLUSIONS

The findings in this study are consistent with that reported in other studies. MAS has a high risk of neonatal mortality. Thus, monitoring during pregnancy and labour is necessary for early identification of high-risk conditions associated with MAS. Strengthening of newborn care services is essential to curtail mortality.

Induction of labor with high- or low-dosage oral misoprostol-A Danish descriptive retrospective cohort study 2015-16

INTRODUCTION

In Denmark, the rate of induced labor from 37 gestational weeks has increased by 108% from 12.4% in 2000 to 25.1% in 2012, and today more than 1 in 4 deliveries are induced. Standard procedure at North Zealand Hospital changed in 2016 from a dosage of 50 µg oral misoprostol 2-3 times daily, to 25 µg up to 8 times daily. Also, since 2016 healthy women with uncomplicated pregnancies (primiparous and multiparous) have been offered induction as an outpatient procedure. This study aimed to compare the current low-dosage procedure (25 µg) with the former high-dosage procedure (50 µg) in terms of induction to delivery time, maternal and fetal outcomes, and risk of uterine hyperstimulation.

MATERIAL AND METHODS

Data from June 2015 to October 2016 were included. Comparable baseline, demographic, and obstetric data for women induced according to high-dosage or low-dosage protocols were retrieved from local medical files. Descriptive statistics, Pearson's chi-squared tests, Kaplan-Meier survival estimates, and logistic regression analyses were performed.

RESULTS

The study included 816 induced deliveries. The high- and low-dosage groups differed in rates of plurality and place of induction. Induction to delivery times lasting longer than 72 hours were significantly decreased in the low-dosage group (adjusted odds ratio [aOR] 0.48, 95% confidence interval [95% CI] 0.27 to 0.86). Women in the low-dosage group also less often needed additional induction (P = 0.02), and the rate of uterine hyperstimulation was low irrespective of protocol (1% vs 3%, P = 0.16). There were no cases of uterine rupture in either group. The probability of vaginal delivery in the low-dosage group increased (adjusted hazard ratio 1.27, 95% CI 1.08 to 1.49), as did the risk of delivery with vacuum extraction (aOR 2.27, 95% CI 1.24 to 4.15), whereas delivery by cesarean section slightly decreased (aOR 0.89, 95% CI 0.59 to 1.33). The risk of meconium-stained liquor was nonsignificantly decreased (aOR 0.82, 95% CI 0.55 to 1.23).

CONCLUSIONS

The low-dosage induction protocol was associated with favorable obstetric outcomes in terms of increased probability of vaginal delivery, but with higher risk of vacuum extraction. Protracted inductions and additional nonmedical interventions were reduced. There were no cases of uterine rupture. Statistically nonsignificant, the risk of uterine hyperstimulation was increased whereas the risk of meconium-stained liquor and of cesarean section was slightly decreased.

Maternal obesity and its association with the mode of delivery and the neonatal outcome in induced labour: Implications for midwifery practice

INTRODUCTION

Maternal obesity carries an increased risk of complications during pregnancy and childbirth. This study investigated whether the body mass index (BMI) of women with induced labour was associated with the mode of delivery and neonatal outcome.

METHODS

This was a retrospective study of primigravidae women under the age of 40 years who were induced at term for various indications. Data were collected from the electronic database of the Maternity Unit where these women gave birth.

RESULTS

We sampled 1274 women with a mean age of 26.3±5.9 years. The mean BMI at booking was 26.5 kg/m², with 28.8% being overweight and 24.3% obese. In the sample, 70.4% had a normal vaginal delivery, 15.4% a caesarean section (CS) and 14.2% an instrumental delivery. An increasing BMI was independently associated with the odds for a CS, with women who were overweight and obese having a 1.58 and 2.75 times greater likelihood for a CS. The CS rate was 10.2% in women with a normal BMI, and increased to 15.8% for overweight and 24.9% for obese women (p<0.001). The increasing BMI did not affect the instrumental delivery rates in our cohort. The Apgar scores at one and five minutes were significantly lower in overweight and obese women compared to women with a normal BMI.

CONCLUSIONS

We show that an increasing BMI in women with induced labour was associated with increased CS rates and lower Apgar scores. These findings highlight the important role of midwives in engaging women in weight management before they get pregnant.

The SaTH risk-assessment tool for the prediction of emergency cesarean section in women having induction of labor for all indications: a large-cohort based study

PURPOSE

To develop a risk-assessment model for the prediction of emergency cesarean section (CS) in women having induction of labor (IOL).

METHODS

This was an observational cohort study of women with IOL for any indication between 2007 and 2013. Women induced for stillbirths and with multiple pregnancies were excluded. The primary objective was to identify risk factors associated with CS delivery and to construct a risk-prediction tool.

RESULTS

6169 women were identified with mean age of 28.9 years. Primiparity involved 47.1 %, CS rate was 13.3 % and post-date pregnancies were 32.4 %. Risk factors for CS were: age >30 years, BMI >25 kg/m², primiparity, black-ethnicity, non post-date pregnancy, meconium-stained liquor, epidural analgesia, and male fetal gender. Each factor was assigned a score and with increasing scores the CS rate increased. The CS rate was 5.4 % for a score <11, while for a score ≥11 it increased to 25.0 %. The model had a sensitivity, specificity, negative predictive value and positive predictive value of 75.8, 65.1, 93.8 and 25.0 %, respectively.

CONCLUSION

We have constructed a risk-prediction tool for CS delivery in women with IOL. The risk-assessment tool for the prediction of emergency CS in induced labor has a high negative-predictive value and can provide reassurance to presumed low-risk women.

Meconium aspiration syndrome: a role for fetal systemic inflammation

BACKGROUND

Meconium aspiration syndrome (MAS) is a leading cause of morbidity and mortality in term infants. Meconium-stained amniotic fluid (MSAF) occurs in approximately 1 of every 7 pregnancies, but only 5% of neonates exposed to MSAF develop MAS. Why some infants exposed to meconium develop MAS while others do not is a fundamental question. Patients with MSAF have a higher frequency of intraamniotic inflammation/infection than those with clear fluid. We propose that fetal systemic inflammation is a risk factor for the development of MAS in patients with MSAF.

OBJECTIVE

We sought to investigate whether intraamniotic inflammation and funisitis, the histopathologic landmark of a fetal inflammatory response, predispose to MAS.

STUDY DESIGN

A prospective cohort study was conducted from 1995 through 2009. Amniotic fluid (AF) samples (n = 1281) were collected at the time of cesarean delivery from women who delivered singleton newborns at term (gestational age ≥38 weeks). Intraamniotic inflammation was diagnosed if the AF concentration of matrix metalloproteinase-8 was >23 ng/mL. Funisitis was diagnosed by histologic examination if inflammation was present in the umbilical cord.

RESULTS

The prevalence of MSAF was 9.2% (118/1281), and 10.2% (12/118) of neonates exposed to MSAF developed MAS. There were no significant differences in the median gestational age or umbilical cord arterial pH at birth between neonates who developed MAS and those who did not (each P > .1). Mothers whose newborns developed MAS had a higher median of AF matrix metalloproteinase-8 (456.8 vs 157.2 ng/mL, P < .05). Newborns exposed to intraamniotic inflammation had a higher rate of MAS than those who were not exposed to intraamniotic inflammation [13.0% (10/77) vs 0% (0/32), P = .03], as did those exposed to funisitis [31.3% (5/16) vs 7.3% (6/82); relative risk, 4.3; 95% confidence interval, 1.5-12.3]. Among the 89 newborns for whom both AF and placental histology were available, MAS was more common in patients with both intraamniotic inflammation and funisitis than in those without intraamniotic inflammation and funisitis [28.6% (4/14) vs 0% (0/28), P = .009], while the rate of MAS did not show a significant difference between patients with intraamniotic inflammation alone (without funisitis) and those without intraamniotic inflammation and funisitis [10.9% (5/46) vs 0% (0/28)].

CONCLUSION

The combination of intraamniotic inflammation with fetal systemic inflammation is an important antecedent of MAS. This concept has implications for the understanding of the mechanisms of disease responsible for MAS and for the development of prognostic models and therapeutic interventions for this disorder.

Should fetal scalp blood sampling be performed in the case of meconium-stained amniotic fluid?

OBJECTIVE

To investigate the effect of using fetal scalp blood sampling on the risk of neonatal respiratory distress syndrome (NRDS) with meconium-stained amniotic fluid (MSAF).

METHODS

Prospective data collection with regard to MSAF during labor for low-risk term cephalic singleton live birth from 2012 to 2014. Maternal, obstetric and neonatal data were compared according to the occurrence of respiratory distress syndrome (RDS group) or not (no RDS group).

RESULTS

Of 515 newborns born through MSAF, 46 experienced RDS and from them 10 experienced meconium aspiration syndrome. No difference was observed according to maternal characteristic, abnormal fetal heart rate tracing pattern irrespective of its category and cesarean rate. Apgar at one minute was lower in the group RDS (7.6 versus 8.5, p < 0.05). The mean umbilical artery pH values did not differ between the two groups. Significant difference between newborns with and without RDS in terms of fetal scalp lactate sampling during the labor (71.1% versus 55.1%, p < 0.05), and neonatal care unit (NCU) admissions (22.8% versus 10.8%, p < 0.05). Secondary rather than primary meconium was associated with RDS when performing fetal scalp blood assessment (p < 0.05). A significant correlation between RDS, fetal scalp blood assessment and MSAF diagnosed during the first stage of labor (after spontaneous rupture of membranes or at amniotomy) was found.

CONCLUSION

In case of MSAF, fetal scalp blood sampling did not reduce the risk of RDS.

Regular Exercise Throughout Pregnancy is Associated with a Shorter First Stage of Labor

Purpose.

The aim of the present study was to examine the influence of moderate physical exercise throughout pregnancy on the duration of labor stages.

Design.

Study was a randomized controlled trial.

Setting.

The study took place at Hospital Puerta de Hierro and Hospital Severo Ochoa in Madrid, Spain.

Subjects.

We examined 166 pregnant women (31.6 ± 3.8 years), and all had uncomplicated and singleton gestation. Of these 83 were allocated to the exercise group (EG) and 83 to the control group (CG).

Intervention.

Women from the EG participated in a physical conditioning program throughout pregnancy, which included 55- to 60-minute sessions, 3 days per week.

Measures.

Pregnancy outcomes were measured: duration of labor stages, gestational age, weight gain, type of delivery, birth weight, birth size, head circumference, Apgar score, pH of umbilical cord.

Analysis.

Student's unpaired t-tests and χ2 tests were used; p values of < .05 indicated statistical significance. Cohen's d was used to determine the effect size.

Results.

Significant differences were found in the duration of the first stage of labor (EG = 389.6 ± 347.64 minutes vs. CG = 515.72 ± 353.36 minutes; p = .02, effect size Cohen's d = .36). The second and third stages did not differ between the study groups.

Conclusion.

A physical exercise program during pregnancy is associated with a shorter first stage of labor. These results may have important relevance to public health.

The aetiology of meconium-stained amniotic fluid: pathologic hypoxia or physiologic foetal ripening? (Review)

INTRODUCTION

Despite the many efforts to study the (patho)physiology of meconium release before delivery, it still remains an indistinct subject. Some studies have reported a relationship between hypoxia and MSAF, whilst others have not. The most common association found however, is between MSAF and the term of gestation.

METHODS

MEDLINE, EMBASE and the Cochrane library were electronically searched. Papers about the (patho)physiology of meconium-stained amniotic fluid in English were included. Papers about management strategies were excluded (see elsewhere this issue).

RESULTS

Different theories have been proposed including acute or chronic hypoxia, physiologic foetal ripening and peripartum infection.

CONCLUSION

We suggest that meconium-stained amniotic fluid should be regarded as a symptom rather than a syndrome becoming more prevalent with increasing term and which might be associated with higher levels of infection or asphyxia.

Secreted phospholipase A2 is increased in meconium-stained amniotic fluid of term gestations: potential implications for the genesis of meconium aspiration syndrome

BACKGROUND

Meconium-stained amniotic fluid (MSAF) represents the passage of fetal colonic content into the amniotic cavity. Meconium aspiration syndrome (MAS) is a complication that occurs in a subset of infants with MSAF. Secreted phospholipase A2 (sPLA2) is detected in meconium and is implicated in the development of MAS. The purpose of this study was to determine if sPLA2 concentrations are increased in the amniotic fluid of women in spontaneous labor at term with MSAF.

MATERIALS AND METHODS

This was a cross-sectional study of patients in spontaneous term labor who underwent amniocentesis (n = 101). The patients were divided into two study groups: (1) MSAF (n = 61) and (2) clear fluid (n = 40). The presence of bacteria and endotoxin as well as interleukin-6 (IL-6) and sPLA2 concentrations in the amniotic fluid were determined. Statistical analyses were performed to test for normality and bivariate analysis. The Spearman correlation coefficient was used to study the relationship between sPLA2 and IL-6 concentrations in the amniotic fluid.

RESULTS

Patients with MSAF have a higher median sPLA2 concentration (ng/mL) in amniotic fluid than those with clear fluid [1.7 (0.98-2.89) versus 0.3 (0-0.6), p < 0.001]. Among patients with MSAF, those with either microbial invasion of the amniotic cavity (MIAC, defined as presence of bacteria in the amniotic cavity), or bacterial endotoxin had a significantly higher median sPLA2 concentration (ng/mL) in amniotic fluid than those without MIAC or endotoxin [2.4 (1.7-6.0) versus 1.7 (1.3-2.5), p < 0.05]. There was a positive correlation between sPLA2 and IL-6 concentrations in the amniotic fluid (Spearman Rho = 0.3, p < 0.05).

CONCLUSION

MSAF that contains bacteria or endotoxin has a higher concentration of sPLA2, and this may contribute to induce lung inflammation when meconium is aspirated before birth.

Bacteria and endotoxin in meconium-stained amniotic fluid at term: could intra-amniotic infection cause meconium passage?

BACKGROUND

Meconium-stained amniotic fluid (MSAF) is a common occurrence among women in spontaneous labor at term, and has been associated with adverse outcomes in both mother and neonate. MSAF is a risk factor for microbial invasion of the amniotic cavity (MIAC) and preterm birth among women with preterm labor and intact membranes. We now report the frequency of MIAC and the presence of bacterial endotoxin in the amniotic fluid of patients with MSAF at term.

MATERIALS AND METHODS

We conducted a cross-sectional study including women in presumed preterm labor because of uncertain dates who underwent amniocentesis, and were later determined to be at term (n = 108). Patients were allocated into two groups: (1) MSAF (n = 66) and (2) clear amniotic fluid (n = 42). The presence of bacteria was determined by microbiologic techniques, and endotoxin was detected using the Limulus amebocyte lysate (LAL) gel clot assay. Statistical analyses were performed to test for normality and bivariate comparisons.

RESULTS

Bacteria were more frequently present in patients with MSAF compared to those with clear amniotic fluid [19.6% (13/66) versus 4.7% (2/42); p < 0.05]. The microorganisms were Gram-negative rods (n = 7), Ureaplasma urealyticum (n = 4), Gram-positive rods (n = 2) and Mycoplasma hominis (n = 1). The LAL gel clot assay was positive in 46.9% (31/66) of patients with MSAF, and in 4.7% (2/42) of those with clear amniotic fluid (p < 0.001). After heat treatment, the frequency of a positive LAL gel clot assay remained higher in the MSAF group [18.1% (12/66) versus 2.3% (1/42), p < 0.05]. Median amniotic fluid IL-6 concentration (ng/mL) was higher [1.3 (0.7-1.9) versus 0.6 (0.3-1.2), p = 0.04], and median amniotic fluid glucose concentration (mg/dL) was lower [6 (0-8.9) versus 9 (7.4-12.6), p < 0.001] in the MSAF group, than in those with clear amniotic fluid.

CONCLUSION

MSAF at term was associated with an increased incidence of MIAC. The index of suspicion for an infection-related process in postpartum women and their neonates should be increased in the presence of MSAF.

New onset of meconium during labor versus primary meconium-stained amniotic fluid - is there a difference in pregnancy outcome?

OBJECTIVE

To compare pregnancy outcome between deliveries complicated by new onset of meconium during labor following prior evidence of clear amniotic fluid and labors in which meconium was present to begin with.

METHODS

A retrospective cohort study of all singleton term (≥37 + 0 weeks) deliveries complicated by intrapartum meconium-stained amniotic fluid in a tertiary referral medical center during the year 2012. Outcome was compared between deliveries with new onset of meconium during labor following prior evidence of clear amniotic fluid (secondary meconium group) and those in which meconium was already evident at the time of membranes rupture (primary meconium group).

RESULTS

Of the 9167 deliveries during the study period, 694 were eligible for the study group. Of these, 537 were complicated by primary meconium and 157 by secondary meconium. Only secondary meconium, but not primary meconium, was independently associated with an increased risk of operative vaginal delivery (OVD) and adverse neonatal outcome. Pregnancies complicated by secondary meconium were independently associated with a higher rate of OVD (28.0% versus 11.4%, p < 0.001), POP position of the fetal head (6.4% versus 2.6%, p = 0.02), and adverse neonatal outcome (17.2% versus 8.9%, p = 0.003).

CONCLUSION

Secondary meconium is associated with a higher rate of adverse obstetrical and neonatal outcome compared with primary meconium.

Is meconium stained amniotic fluid related to occult myocardial injury in term low risk pregnancies?

AIM

The present study aimed to compare Troponin T (Tp T) levels of infants born with meconium stained amniotic fluid (MSAF) to those with clear amniotic fluid.

STUDY DESIGN

Case-control study

SUBJECTS

Thirty-five women who had delivery complicated by MSAF between 37 and 41weeks of gestation were defined as the study group and women with healthy uncomplicated pregnancies with clear amniotic fluid who were matched for age, parity, and gestational age were defined as the control group.

OUTCOME MEASURES

Cord blood Tp T level, gas analysis and neonatal outcomes were compared between groups.

RESULTS

Tp T levels of the study and control groups were 0.026±0.013ng/ml and 0.031±0.016ng/ml, respectively. The difference was not statistically significant (p=0.132). On the other hand, the study group had a statistically lower HCO(3) level (21.80 vs 23.60mmol/l ) and higher rate of base deficit (4.85 vs 3.25mmol/l) than the control group.

CONCLUSION

The presence of meconium during labor is not related to occult myocardial injury in low-risk term pregnancies.