Meconium stained liquor and meconium aspiration syndrome: the facts

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baby mum Photo: Getty Images

What are meconium stained liquor and meconium aspiration syndrome?

Most infants have their first bowel movement, called meconium, in the first 24 hours after delivery. Mecomium is a sticky dark-green consistency, and when the amniotic fluid is tinted green or yellow, instead of being clear, it is called meconium stained liquor. This happens when an infant passes meconium before they are born.

Meconium aspiration syndrome is when an infant inhales the meconium before, during or after labour. It can cause respiratory problems as serious as pneumonia, and although it rarely happens, it can be fatal.

Not all babies who are born with meconium staining will develop meconium aspiration syndrome, and those that do usually have their airways cleared quickly to prevent further health problems.

What are the risk factors? 

Chances of meconium stained liquor and meconium aspiration syndrome are raised if any of the following are present: 

- foetal distress during labour (such as having a difficult delivery or umbilical cord problems)
- being an older mother
- smoking cigarettes
- having medical conditions such as diabetes, high blood pressure or cardiovascular problems
- having an infection or placenta problems
- being overdue (meconium staining rarely occurs before 38 weeks of pregnancy).

What are the signs?

Besides stained amniotic fluid, other signs a baby may have meconium aspiration syndrome include breathing difficulties, a slow heartbeat, a distended chest or making “grunty” noises, and receiving a low APGAR score (which is based on a few different tests that evaluate a baby’s health straight after birth).

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How are they diagnosed?

Meconium stained liquor is diagnosed through observation of the amniotic fluid.

Meconium aspiration syndrome can be diagnosed by listening to a baby’s lungs with a stethoscope for wet or crunchy sounds. If they can be heard, chest X-rays can be ordered to show patchy areas on the lungs. Blood can also be taken to show how much oxygen an infant has in their circulation, which can both be used to make a final diagnosis and start treatment.

What's the treatment?

Meconium stained liquor observed during labour is a signal for increased monitoring of the baby during labour.

Treatment depends on how much meconium is inhaled. If meconium staining can be seen during labour, an amniofusion can be performed to prevent aspiration syndrome. This is when the meconium is flushed out of the amniotic fluid with a saline solution before the baby can inhale it, although this practice isn’t usually performed in Australia.

If a baby has inhaled meconium but their heartbeat or breathing isn’t affected, they will be monitored but may not require any treatment.

Doctors can perform suction to remove the meconium from the trachea and lungs until it’s all gone. The baby may sometimes need antibiotics.

Some babies who have inhaled a lot of meconium will need to be placed on a ventilator and cared for in a neo-natal intensive unit. Many babies will be fine within a matter of days or weeks, although very rarely a baby may experience longer-term health issues such as asthma or developmental problems.

Do they affect the mother?

Meconium staining doesn’t affect the mother’s health, unless it occurs because of other complications that will need to be treated separately.

Facts verified by Dr Andrew Zuschmann. Dr Andrew Zuschmann is a Miranda-based fertility specialist, obstetrician and gynaecologist.