Understanding Meconium-Stained Amniotic Fluid (MSAF)

What is Meconium?
Meconium is the first stool passed by a baby, made up of intestinal cells, lanugo, mucus, bile, and water. It is typically thick, sticky, and greenish-black. Most babies pass meconium within the first 24–48 hours after birth.

What is Meconium-Stained Amniotic Fluid (MSAF)?
Sometimes, a baby passes meconium into the amniotic fluid before birth. This can tint the fluid green or brown and is called meconium-stained amniotic fluid. MSAF occurs in about 12% of all births and is more common in:

  • Post-term pregnancies (after 41 weeks)

  • Labors involving stress for the baby

  • Cases of maternal hypertension or infection

  • Pregnancies with growth-restricted babies

What is Meconium Aspiration Syndrome (MAS)?
MAS happens when a baby inhales (aspirates) meconium-stained fluid into the lungs either before, during, or shortly after birth. This can cause:

  • Blockage of airways

  • Lung inflammation

  • Difficulty breathing

  • In severe cases, the need for advanced respiratory support

What Are the Risks Associated with MAS?
While most babies exposed to MSAF do not develop MAS, the condition can be serious. Risks include:

  • Breathing difficulties at birth

  • Pneumonia or infection

  • Need for NICU admission

  • In rare cases, long-term lung issues or even death

  • Mortality in MAS is close to 1.2 percent based on a large retrospective study in the United States

How Is MSAF Managed in Out-of-Hospital Births?
Your midwifery team is trained to assess and respond to MSAF. Here's what to expect:

  • Close monitoring during labor: We watch for signs of fetal distress and assess the color and consistency of the amniotic fluid.

  • Individualized decision-making: Thin or lightly stained fluid with reassuring fetal heart tones may not require changes in birth plan. Thick, particulate meconium or signs of distress may prompt a transfer to a hospital setting unless birth is imminent.

  • Immediate newborn care: If MSAF is present, we are prepared to evaluate the baby's breathing and provide gentle suction or resuscitation only if needed. In some cases, we may recommend pediatric evaluation.

Prevention and Communication Are Key

  • Regular prenatal care helps monitor the baby's well-being.

  • Discuss your preferences and concerns with your midwives.

  • If you are beyond 41 weeks, we may recommend additional testing or monitoring to evaluate the baby's condition.

Takeaway Message
MSAF is not always an emergency, but it does require attention and experience. At DFW Community Birth & Wellness, we are equipped to assess and respond, we want you to know that YOU are in charge of the decision making as well. During your birth planning session we’ll review your comfort level of MSAF and if it’s present at your birth we will once again go over informed consent with your options.

Please reach out to us with any questions or if you notice a decrease in fetal movement, changes in amniotic fluid, or feel unsure about anything in your pregnancy.