Today, we are going to talk about Pitocin.
Pitocin is the most popular drug used to stimulate contractions of the uterus to induce or quicken labor. Many providers also use it to reduce bleeding after delivery.
In order to understand Pitocin, we need examine the history of the hormone oxytocin.
The word oxytocin comes from the Greek term oxytocic, meaning “quick birth”. In 1906 by Sir Henry Hallett Dale discovered that oxytocin was vital to uterine contractions.1 but was not sequenced or synthesized until the 1950s by Vincent du Vigneaud. Du Vigneaud received a Noble Prize for his work2.
Up to that point, in order to use oxytocin to start or quicken labor you must harvest it from cattle at the slaughterhouse. This practice had been going on since 1909. Oxytocin harvested from cattle, called Pituitrin, was a safer alternative to Ergot at the time. Ergot at certain concentrations is toxic to humans. It also produces irregular and severely intense contractions. These contractions caused tearing simply from the immense strength of them.
Pituitrin could produce contractions that were more predictable than Ergot. At the time, the only way to administer Pituritrin was via injection, instead of intravenously. As a result, contractions were still irregular and hard to control. Common negative side effects included reactions to the animal proteins, uterine rupture, embolism and even maternal and/or fetal death. Still, Pituitrin was now favored over Ergot and the very common use of forceps (yes more common even then today!)
Pitocin hits the market.
Fast forward to 1928, and the pharmaceutical company Parke Davis introduced the drug Pitocin. This separated it from the negativity that had built surrounding Pituitrin. In 1928, Pitocin, like Pituitrin, was still harvested from cattle, but the chemical formula had been refined. The outcome was better, but not by much. This is where du Vigneaud’s discovery in 1953 becomes important. Not only was he able to synthesize it, but so were others.
This was the turning point. Now they could produce synthesized oxytocin in larger quantities and hold it to a quality standard. No more animal proteins. Dosages were much easier to calculate. The biggest change however was administering Pitocin intravenously. Now the synthesized hormone was coming in waves, increasingly similar to the body’s natural flow. This easier than in the past to predict and adjust to control contractions.3
Is Pitocin different then oxytocin?
Pitocin, while synthetically made, is identical to the oxytocin made by the body. However, many women report that contractions are more painful, more intense, and/or closer together in contrast to contractions produced without augmentation. Studies have shown that the physiology of the contractions is the same. Many professionals postulate that because Pitocin cannot pass easily through the blood brain barrier contractions produced from it are more intense because the body does not build up the same amount of endorphins in response. Endorphins help reduce the perception of pain 4.
Other explanations for the difference include the inability of the body to regulate the Pitocin as it naturally does with oxytocin. Pitocin, given continuously at a steady dosage, cannot adjust to changes in other hormones in the body. A steady IV is still the preferred method because the synthesized hormone is only active in the body for around three to six minutes.5
Knowing all of this, what are some reasons your care provider might encourage induction with Pitocin?
- Past Term – this varies by OB/midwife but ACOG recommends after 41 weeks
- High Blood Pressure – High BP is not good for you or baby and can come with a diagnosis of preeclampsia. The only cure for preeclampsia is to deliver baby.
- Your water breaks but labor does not start within 12 hours – Your amniotic sac acts as a cushion and barrier for baby.
- Once the sac has broken the risk of infection increases.
- Gestational Diabetes
- Fetal Growth Restriction – there are times that for various reasons baby is not receiving the nutrients that it needs in order to continue growing.6
Side effects of Pitocin can include, but are not limited to, headache, nausea, blood pressure spikes, difficulty breathing, dizziness, and weakness in the mother.7 Side effects for newborns are not as clearly studied. A recent study has suggested that use of Pitocin to start or quicken labor correlates with an increased liklihood of NICU stays in full term babies and lower initial APGAR scores. Dr. Tsimis, who conducted the study concluded “we don’t want to discourage the use of Pitocin, but simply want a more systematic and conscientious approach to the indications for its use.”8
What does this mean for you?
Make sure to talk through the suggestion to induce or augment labor with Pitocin, the reasons for the suggestion, any alternatives, and any concerns you have about side effects with your provider. Only you and your provider can determine what is best in each individual situation.
1. “On some physiological actions of ergot” by H. H. Dale. Published: J Physiol. 1906 May 31; 34(3): 163–206.
2. “The Synthesis of Oxytocin” by Vincent du Vigneaud, Charlotte Ressler, John M. Swan, Carleton W. Roberts, Panayotis G. Katsoyannis. Published: J. Am. Chem. Soc., 1954, 76 (12), pp 3115–3121
3. “Managing Labor with Pitocin: Medical Discourse and Decision-Making in Contemporary Clinical Settings” by Anna Hermann PDF
4. “Induction, A Step by Step Guide” by Midwife Thinking.
5. “Oxytocin and vasopressin: linking pituitary neuropeptides and their receptors to social neurocircuits” by Danielle A. Baribeau and Evdokia Anagnostou.
6. “Optimizing Protocols in Obstetrics: Oxytocin for Induction” by The American Congress of Obstetricians and Gynecologists. PDF
8. “Study Finds Adverse Effects of Pitocin in Newborns” by The American Congress of Obstetricians and Gynecologists.