Written by:

Dr Tom Pettinger

MBChB, MRCOG

Dr. Pettinger is a specialist registrar in obstetrics and gynaecology, working in hospitals throughout West Yorkshire. He is currently completing advanced training in benign gynaecological surgery and obstetrics, and is particularly interested in improving communication in maternity care.

Passing meconium before birth

In this article:

  • Main points
  • Reference:

Passing meconium before birth

Meconium (often abbreviated to “meck”) is the greeny-black poo that is in your baby’s bowel before they’ve ever drunk milk. It’s a different colour because it’s made only of debris floating around in the amniotic fluid, which your baby is swallowing all the time inside your womb.

Sometimes midwives or doctors notice that the fluid around your baby has a greenish tinge to it, or even has little lumps of meconium. We don’t yet know how significant this is. If your baby is past their due date, it’s quite a common finding; of the babies born at term, 15-20% will have meconium in their amniotic fluid. But the earlier you are delivering your baby, the more unusual it is, and it is sometimes thought to suggest that the baby has had a moment of distress. If there is really thick, lumpy meconium present, it can get stuck in a baby’s throat and make it difficult for them to take their first breaths. It is also an irritant and, rarely, babies can inhale it and hurt their lungs. These babies will need extra treatment when they’re born and will need to be admitted to a Special Care Baby Unit.

If your midwife or doctor tells you they’ve seen meconium, don’t panic. It does not mean your baby is distressed at that moment, and the vast majority of babies where meconium is seen have no problems whatsoever. The main ways it will affect your labour experience are:

  • If you weren’t having your baby’s heartbeat monitored constantly, your doctors will recommend it.
  • If your waters have just broken (naturally or by a midwife/doctor) but you’re not contracting, your doctors may suggest starting a hormone drip immediately to help induce labour rather than waiting to see when labour occurs.

Starting a drip is not an easy decision, as there is no good evidence to suggest one course of action or another. Starting the drip immediately will mean everyone gets to see how labour progresses sooner rather than later. But the drip can be associated with over-contracting, which would add to any distress for your baby. Often, the decision to start the drip comes down to practical reasons. Once meconium has been seen, your midwife and doctor will recommend that the baby’s heartbeat be monitored constantly with a CTG. If you are not yet contracting, the only alternative to starting the drip immediately is to continue with monitoring while you await the onset of labour.

Main points

  • Meconium is the greeny black poo that is in your baby’s bowel before it has ever drunk milk.
  • If your baby is past their due date, it’s quite common for them to have already passed meconium.
  • If you deliver your baby early, the presence of meconium may be a sign of distress.
  • Meconium is an irritant and, rarely, babies can inhale it and hurt their lungs. These babies will need to be admitted to a Special Care Baby Unit.
  • Meconium can affect your birthing experience. If it’s seen, your baby will have their heartbeat monitored constantly (if you weren’t already) and your doctors may suggest starting a drip to help bring on contractions.

Reference:

Best Practice in Labour and Delivery. p18. Cambridge University Press, 2010.