The use of prostaglandins, or an oxytocin drip, can sometimes overstimulate the woman's uterus (or make it contract 'too much'). These are known as 'tonic contractions'. The chances of a woman experiencing tonic contractions usually depend on her individual sensitivity to the drug being used and / or whether she has laboured before. Women having their second or subsequent labour, are much more responsive to these drugs.
Overstimulation is not that common, but can be very unpredictable. If it does occur, the uterus can contract, almost continuously, for several minutes. Prolonged contractions do not give the baby any recovery time, and reduce the oxygen they can obtain from the placenta, causing them to become distressed. The mother can also become distressed as she struggles to cope with these intense, prolonged contractions.
Even though overstimulation of the uterus is fairly rare, it can lead to a rapid cascade of quite serious interventions. If it is caused by prostaglandins, the medication cannot be reversed, or removed. Therefore, the treatment is to have an immediate Caesarean operation using a
general anaesthetic, (because there is no time to insert an epidural), with the baby often needing to be
resuscitated (and possibly cared for in the intensive care nursery if they are unwell). Tonic contractions can sometimes be life-threatening for the baby.
If the woman experiences tonic contractions with an oxytocin drip, the caregiver is able to turn the drip down (or off) to reduce the contractions, and allow time for the baby to recover. The woman may also be given oxygen to help the baby. Sometimes the baby will become distressed again, every time the oxytocin is turned back on. This means the induction is unsuccessful and a Caesarean would be required.
Positive points......