The drug Pitocin is a synthetic form of the hormone oxytocin, which triggers the onset of labor. Pitocin can be administered intravenously to induce labor or make contractions faster and stronger. While Pitocin can have some notable benefits, such as preventing dangerously lengthy labor, promoting breast milk secretion, and controlling bleeding after delivery, its use in labor induction also carries serious risks. It is difficult to predict how an individual woman will respond to doses of Pitocin: the effects vary widely, from no clear impact on uterine activity to severe harm to mother and baby. One of the major negative outcomes in infants is the development of hypoxic-ischemic encephalopathy (insufficient oxygen and blood flow around the time of birth, sometimes leading to forms of brain damage such as cerebral palsy).
Uterine Hyperstimulation and HIE
In a healthy labor, it is normal for blood flow in and out of the placenta to slow or stop during contractions. However, there should be sufficient time between contractions for the placenta to be “at rest,” during which oxygen-rich blood flows freely to the baby. Without this resting time, the baby’s oxygen will be in short supply.
Pitocin use can cause hyperstimulation of the uterus, meaning contractions are excessively frequent, long, or intense. Hyperstimulation can limit the flow of oxygen through the uterus, placenta, and umbilical cord, resulting in fetal oxygen deprivation.
If a patient’s uterus becomes hyperstimulated, doctors should cease administering Pitocin immediately. If there are signs of fetal distress, such as an abnormally slow or fast heart rate, this is usually an indication that the fetus is deprived of oxygen and medical intervention is necessary. Generally, this takes the form of an emergency C-section.
Uterine Rupture and HIE
One of the most drastic pregnancy complications resulting from hyperstimulation is uterine rupture, which can occur when contractions are too intense. One study found that 77% of mothers who experienced uterine rupture had been given Pitocin. The chance of Pitocin use leading to uterine rupture is especially high in women who are having a vaginal birth after cesarean (VBAC).
Uterine rupture can harm an infant in a few ways:
- Maternal hemorrhaging diverts oxygenated blood away from the baby. It is also very dangerous to the mother.
- The baby is no longer confined to the uterus and begins moving up toward the abdomen, causing the umbilical cord to become stretched, compressed, or torn, and therefore unable to supply an adequate amount of oxygen.
- Uterine rupture can cause the placenta to become partially or completely detached from the uterus (placental abruption), cutting off the flow of oxygenated blood between the two
Uterine rupture can cut off the fetus’s oxygen supply, and, like other complications from uterine hyperstimulation, may lead to hypoxic-ischemic encephalopathy and severe brain damage.
Appropriate and Inappropriate Pitocin Use
There are situations in which induction with Pitocin is an appropriate course of action (mainly, if the risks of continuing with the pregnancy outweigh the risks of artificial induction). However, due to the potential of Pitocin to cause HIE and other serious conditions, it should only be used for medically-necessary inductions. It should also be avoided in women who have a history of premature delivery, genital herpes, C-section, uterine or cervical surgery. Moreover, its use is very dangerous in pregnancies in which the fetus, placenta, or umbilical cord is in an unusual position, or if uterine activity is abnormal. Finally, it should be avoided if the mother’s pelvis is small relative to the infant’s head (cephalopelvic disproportion).
Doctors administering intravenous Pitocin should be aware of its risks, and extremely vigilant for signs of fetal distress during delivery. They should also be prepared for the possibility of an emergency C-section if uterine hyperstimulation occurs and puts the mother and/or baby in jeopardy.
The information presented above is intended only to be a general educational resource. It is not intended to be (and should not be interpreted as) medical advice. If you have questions about Pitocin, please consult with a medical professional.
- Signs of Fetal Distress
- Oxytocin Injection
- Oxytocin (By injection)
- Risk factors associated with uterine rupture during trial of labor after cesarean delivery: A case-control study