Oxytocin in pregnancy and the postpartum: relations to labor and its management

• Main Authors: Marie ePrevost, Phyllis eZelkowitz, Togas eTulandi, Barbara eHayton, Nancy eFeeley, C. Sue eCarter, Lawrence eJoseph, Hossein ePournajafi-Nazarloo, Erin eYong Ping, Haim eAbenhaim, Ian eGold
• Format: Article
• Language: English
• Published: Frontiers Media S.A. 2014-01-01
• Series: Frontiers in Public Health
• Subjects: Oxytocin; Pregnancy; epidural; Postpartum; labour; syntocinon
• Online Access: http://journal.frontiersin.org/Journal/10.3389/fpubh.2014.00001/full

The purpose of this study was to examine variations in endogenous oxytocin levels in pregnancy and postpartum state. We also explored the associations between delivery variables and oxytocin levels. A final sample of 272 mothers in their first trimester of pregnancy were included for the study. Blood samples were drawn during the 1st trimester and 3rd trimester of pregnancy and at 8 weeks postpartum. Socio-demographic data were collected at each time point and medical files were consulted for delivery details. In most women, levels of circulating oxytocin increased from the 1st to 3rd trimester of pregnancy followed by a decrease in the postpartum period. Oxytocin levels varied considerably between individuals, ranging from 50 pg/mL to over 2000 pg/mL. Parity was the main predictor of oxytocin levels in the 3rd trimester of pregnancy and of oxytocin level changes from the 1st to the 3rd trimester of pregnancy. Oxytocin levels in the 3rd trimester of pregnancy predicted a self-reported negative labor experience and increased the chances of having an epidural. Intrapartum exogenous oxytocin was positively associated with levels of oxytocin during the postpartum period. Our exploratory results suggest that circulating oxytocin levels during the 3rd trimester of pregnancy may predict the type of labor a woman will experience. More importantly, the quantity of intrapartum exogenous oxytocin administered during labor predicted plasma oxytocin levels 2 months postpartum, suggesting a possible long-term effect of this routine intervention, the consequences of which are largely unknown.