Meconium is the initial substance present in the intestines of the developing fetus and constitutes the first bowel movement of the newborn. Meconium can be green, brown, or yellow. Term healthy neonates pass meconium between 24 to 48 hours following birth. Preterm infants typically exhibit delayed passage.
The presence of meconium-stained amniotic fluid is about 12-20% of deliveries and is much higher in post-dated births (up to 40%). In-utero passage of meconium may indicate normal gastrointestinal maturation or more concerningly it may be a sign of acute or chronic fetal hypoxia. Some of the conditions associated with meconium passage in-utero include placental insufficiency, preeclampsia, oligohydramnios, peripartum infections, and certain maternal drugs such as cocaine. Babies born through a meconium-stained amniotic fluid are at higher risk of development of adverse events such as perinatal asphyxia and respiratory distress. The accidental inhalation of meconium in-utero or during delivery can result in an adverse event for the infant, which is known as meconium aspiration syndrome. This complication happens in about 3-9% of the babies delivered with meconium-stained amniotic fluid. To reduce the risk of adverse consequences related to meconium-stained amniotic fluid, the American College of Obstetricians and Gynecologists 2014 guidelines recommend induction of labor at or after 42 weeks. Similarly, induction of labor is to be considered between 41- 42 weeks of gestation. In-utero passage of meconium before 32 weeks of gestation is rare, and in preterm babies, meconium-stained amniotic fluid may indicate chorioamnionitis, fetal sepsis (e.g., listeriosis) or in-utero cord compression.
The passage of meconium within 24-48 hours after birth indicates that the intestines of the newborn are intact and patent. This assessment is important for the initial newborn examination. Failure to pass meconium beyond 48 hours in term neonates may indicate disease or obstruction of the infant's bowel. The diagnostic differential for the delayed passage of meconium includes Hirschsprung disease, meconium plug syndrome, meconium ileus, anorectal malformations, small left colon syndrome, and intestinal atresias. Hypothyroidism, sepsis, and electrolyte abnormalities (hypercalcemia, hypokalemia), and maternal medications (magnesium sulfate, illicit drugs) can also delay the passage of meconium.
In the event of the rupture of the fetal membranes, the nurse should assess the color of the amniotic fluid. Amniotic fluid should be clear, or straw tinged with small vernix particles in the fluid. Brown or green staining of the fluid indicates the passage of meconium. Because the fetus swallows amniotic fluid in utero, meconium can be present in the infant's oropharynx at delivery. During delivery, if meconium-stained amniotic fluid is noted, a neonatal resuscitation team should be promptly involved.
Traditionally, during labor, if meconium-stained amniotic fluid is encountered, an intrapartum suctioning of airways was done. Latest guidelines recommend changing these practices quoting that these procedures are of unknown benefit and may be even harmful. In the updated 2015 American Heart Association/American Academy of Pediatrics guidelines (AHA/AAP), routine intrapartum suctioning of the airways before the delivery of the shoulders is not recommended.
If the infant is vigorous with good muscle tone and respiratory efforts, further newborn care could be provided in the delivery room. Routine suctioning of the meconium-stained fluid from the oropharynx is not recommended in these infants. However, if the airway is obstructed, then the airway clearance with suctioning of the meconium is recommended. Close monitoring in the newborn nursery is warranted.
If the infant is not vigorous with poor neurological tone, insufficient breathing efforts, and bradycardia (heart rate <100 beats/minute), routine postnatal suctioning of the airways was widely practiced in the past to decrease the possibility of development of meconium aspiration syndrome. The 2015 AHA/AAP guidelines do not recommend this practice and rather recommend immediate appropriate management to support ventilation and oxygenation, such as commencing positive pressure ventilation. Interventions such as endotracheal intubation for positive pressure ventilation may be required in severe instances, and a prompt transfer to the neonatal intensive care unit for further management may be needed. Airway clearance with suctioning of the meconium is recommended if the airway is obstructed. The 2015 AHA/AAP guidelines emphasize on following the same resuscitation steps for infants with a meconium-stained amniotic fluid similar to those infants with clear fluid.
During labor, the assessment of the amniotic fluid color can determine if the infant is at risk for amniotic inhalation upon birth. If the meconium-stained amniotic fluid is noted, a neonatal resuscitation team should be involved. In places with limited perinatal resources, an amnioinfusion could be tried, but the benefits of this procedure are unclear. Latest guidelines emphasize on following the same resuscitation measures for infants with a meconium-stained amniotic fluid similar to those infants with clear fluid. The assessment of respirations, color, and signs of respiratory distress (grunting, nasal flaring, intercostal retractions, and tachypnea) are necessary after birth. Assessment for passage of meconium, which usually occurs during the first twenty-four hours of life, is part of the initial newborn examination and indicates an unobstructed gastrointestinal tract with a patent anus.
|||Singh A,Mittal M, Neonatal microbiome - a brief review. The journal of maternal-fetal [PubMed PMID: 30835585]|
|||Scholfield DW,Ram AD, The importance of recording first passage of meconium in neonates. BMJ (Clinical research ed.). 2017 Mar 2 [PubMed PMID: 28254949]|
|||Clark DA, Times of first void and first stool in 500 newborns. Pediatrics. 1977 Oct [PubMed PMID: 905009]|
|||Arnoldi R,Leva E,Macchini F,Di Cesare A,Colnaghi M,Fumagalli M,Mosca F,Torricelli M, Delayed meconium passage in very low birth weight infants. European journal of pediatric surgery : official journal of Austrian Association of Pediatric Surgery ... [et al] = Zeitschrift fur Kinderchirurgie. 2011 Dec [PubMed PMID: 22169992]|
|||Bekkali N,Hamers SL,Schipperus MR,Reitsma JB,Valerio PG,Van Toledo L,Benninga MA, Duration of meconium passage in preterm and term infants. Archives of disease in childhood. Fetal and neonatal edition. 2008 Sep [PubMed PMID: 18285377]|
|||Mundhra R,Agarwal M, Fetal outcome in meconium stained deliveries. Journal of clinical and diagnostic research : JCDR. 2013 Dec [PubMed PMID: 24551662]|
|||Shaikh EM,Mehmood S,Shaikh MA, Neonatal outcome in meconium stained amniotic fluid-one year experience. JPMA. The Journal of the Pakistan Medical Association. 2010 Sep [PubMed PMID: 21381573]|
|||Monen L,Hasaart TH,Kuppens SM, The aetiology of meconium-stained amniotic fluid: pathologic hypoxia or physiologic foetal ripening? (Review). Early human development. 2014 Jul [PubMed PMID: 24794302]|
|||Poggi SH,Ghidini A, Pathophysiology of meconium passage into the amniotic fluid. Early human development. 2009 Oct; [PubMed PMID: 19836908]|
|||Wiswell TE, Appropriate Management of the Nonvigorous Meconium-Stained Neonate: An Unanswered Question. Pediatrics. 2018 Dec [PubMed PMID: 30385638]|
|||Practice bulletin no. 146: Management of late-term and postterm pregnancies. Obstetrics and gynecology. 2014 Aug [PubMed PMID: 25050770]|
|||Lamont RF,Sobel J,Mazaki-Tovi S,Kusanovic JP,Vaisbuch E,Kim SK,Uldbjerg N,Romero R, Listeriosis in human pregnancy: a systematic review. Journal of perinatal medicine. 2011 May [PubMed PMID: 21517700]|
|||Brabbing-Goldstein D,Nir D,Cohen D,Many A,Maslovitz S, Preterm meconium-stained amniotic fluid is an ominous sign for the development of chorioamnionitis and for in utero cord compression. The journal of maternal-fetal & neonatal medicine : the official journal of the European Association of Perinatal Medicine, the Federation of Asia and Oceania Perinatal Societies, the International Society of Perinatal Obstetricians. 2017 Sep [PubMed PMID: 28282782]|
|||Chou YC,Chang WT, Prenatal Diagnosis of Anal Atresia - A Case Report. Journal of medical ultrasound. 2017 Jul-Sep; [PubMed PMID: 30065486]|
|||Enríquez Zarabozo E,Núñez Núñez R,Ayuso Velasco R,Vargas Muñoz I,Fernández de Mera JJ,Blesa Sánchez E, [Anorectal manometry in the neonatal diagnosis of Hirschsprung's disease]. Cirugia pediatrica : organo oficial de la Sociedad Espanola de Cirugia Pediatrica. 2010 Jan; [PubMed PMID: 20578577]|
|||Stanyer R,Hopper H, Is the incorporation of the newborn examination in the pre-registration curriculum acceptable in clinical practice? A qualitative study. Nurse education in practice. 2019 Feb; [PubMed PMID: 30785063]|
|||Vargas MG,Miguel-Sardaneta ML,Rosas-Téllez M,Pereira-Reyes D,Justo-Janeiro JM, Neonatal Intestinal Obstruction Syndrome. Pediatric annals. 2018 May 1; [PubMed PMID: 29750290]|
|||Loening-Baucke V,Kimura K, Failure to pass meconium: diagnosing neonatal intestinal obstruction. American family physician. 1999 Nov 1 [PubMed PMID: 10569507]|
|||Wosenu L,Worku AG,Teshome DF,Gelagay AA, Determinants of birth asphyxia among live birth newborns in University of Gondar referral hospital, northwest Ethiopia: A case-control study. PloS one. 2018; [PubMed PMID: 30192884]|
|||Chettri S,Bhat BV,Adhisivam B, Current Concepts in the Management of Meconium Aspiration Syndrome. Indian journal of pediatrics. 2016 Oct; [PubMed PMID: 27206687]|
|||Chabra S, Evolution of Delivery Room Management for Meconium-Stained Infants: Recent Updates. Advances in neonatal care : official journal of the National Association of Neonatal Nurses. 2018 Aug [PubMed PMID: 29889726]|
|||Committee Opinion No 689: Delivery of a Newborn With Meconium-Stained Amniotic Fluid. Obstetrics and gynecology. 2017 Mar [PubMed PMID: 28225424]|
|||Wyckoff MH,Aziz K,Escobedo MB,Kapadia VS,Kattwinkel J,Perlman JM,Simon WM,Weiner GM,Zaichkin JG, Part 13: Neonatal Resuscitation: 2015 American Heart Association Guidelines Update for Cardiopulmonary Resuscitation and Emergency Cardiovascular Care. Circulation. 2015 Nov 3 [PubMed PMID: 26473001]|
|||Aldhafeeri FM,Aldhafiri FM,Bamehriz M,Al-Wassia H, Have the 2015 Neonatal Resuscitation Program Guidelines changed the management and outcome of infants born through meconium-stained amniotic fluid? Annals of Saudi medicine. 2019 Mar-Apr; [PubMed PMID: 30955017]|
|||Hofmeyr GJ,Xu H,Eke AC, Amnioinfusion for meconium-stained liquor in labour. The Cochrane database of systematic reviews. 2014 Jan 23 [PubMed PMID: 24453049]|
|||Okoro PE,Enyindah CE, Time of passage of First Stool in Newborns in a Tertiary Health Facility in Southern Nigeria. Nigerian journal of surgery : official publication of the Nigerian Surgical Research Society. 2013 Jan; [PubMed PMID: 24027413]|
|||Solaz-García AJ,Segovia-Navarro L,Rodríguez de Dios-Benlloch JL,Benavent-Taengua L,Castilla-Rodríguez DY,Company-Morenza MA, Prevention of meconium obstruction in very low birth weight preterm infants. Enfermeria intensiva. 2019 Apr - Jun; [PubMed PMID: 30245147]|
|||Singh AK,Pandey A,Rawat J,Singh S,Wakhlu A,Kureel SN, Management Strategy of Meconium Ileus-Outcome Analysis. Journal of Indian Association of Pediatric Surgeons. 2019 Apr-Jun; [PubMed PMID: 31105398]|