Intrapartum Administration of Synthetic Oxytocin and Downstream Effects on Breastfeeding: Elucidating Physiologic Pathways

Research Article

Ann Nurs Res Pract. 2017; 2(3): 1024.

Intrapartum Administration of Synthetic Oxytocin and Downstream Effects on Breastfeeding: Elucidating Physiologic Pathways

Cadwell K* and Brimdyr K

Healthy Children Project, Inc., The Center for Breastfeeding, USA

*Corresponding author: Karin Cadwell, The Center for Breastfeeding, Healthy Children Project, Inc. 327 Quaker Meeting House Road, East Sandwich, MA 02537, USA

Received: November 30, 2017; Accepted: December 18, 2017; Published: December 26, 2017


The importance of breastfeeding as a public health priority has increased as new research reinforces the health benefits to both mother and nursling, even continuing years after weaning. However, many women do not nurse as long as they intend. Birth practices such as labor medications and the routine separation of mother and baby are two of the several intrapartum influences on breastfeeding outcomes. This paper seeks to elucidate the physiologic mechanisms affecting breastfeeding outcomes of the commonly administered intrapartum drug, synthetic oxytocin.

A modified ascending, link tracing methodology was used to identify studies about breastfeeding and human lactation which describe possible physiologic pathways related to the intrapartum use of synthetic oxytocin on breastfeeding outcomes. A cascade model was constructed with the findings of three physiologic pathways: dysregulation of the maternal OT system, crossing of the fetal blood brain barrier, and uterine hyper stimulation. Downstream negative effects related to breastfeeding include decreased maternal endogenous oxytocin, increased risk of negative neonatal outcomes, decreased neonatal rest during the first hour with the potential of decreasing the consolidation of memory, decreased neonatal pre-feeding cues, decreased neonatal reflexes associated with breastfeeding, maternal depression, somatic symptoms and anxiety disorders. No positive relationships between the administration of synthetic oxytocin and breastfeeding were found. Practices that could diminish the nearly ubiquitous practice of inducing and accelerating labor with the use synthetic oxytocin should be considered when evaluating interventions that affect breastfeeding outcomes.

Keywords: Breastfeeding; Oxytocin; Pitocin; Labor; Synthetic oxytocin


The United States’ Healthy People Goals have included measurements of breastfeeding rates since their inception in the late 1970’s. However, only since a United States’ government funded research analysis of breastfeeding’s relationship to maternal and child health outcomes in 2007 [1] was published, have credible cost estimates of the contribution of suboptimal breastfeeding been published [2,3]. The most recent calculation [4] includes not only the money spent on nine pediatric and five maternal diseases, (billions of dollars), but also the calculation that for every 597 women who optimally breastfeed in the United States, one maternal or child death could be prevented.

The recently published document, Recommendations for Preventative Services for Women Final Report to the US. Department of Health and Human Services, Health Resources & Services Administration [5] includes, as one of the preventive measures for improving public health for women, their families and communities, improving access to breastfeeding services and supplies. The 2017 copyright holder is the American College of Obstetrics and Gynecologists (ACOG), although an interdisciplinary team, including government representatives, took part in the process of developing the document. Interventions both at the individual level (education, counseling and mother-to mother support, for example) and system level (such as the Baby-Friendly Hospital Initiative, training of health professionals, practices such as skin-to-skin care and rooming-in) are cited as having been shown to be effective in increasing breastfeeding initiation and intensity.

Of note is the absence from the report of intrapartum interventions (such as continuous labor support by doulas or birth attendants) that have been demonstrated to have a positive influence on breastfeeding outcomes [6]; the recommendations also do not address intrapartum medications that have been shown to have a negative influence on breastfeeding outcomes. This study seeks to identify the physiological pathways and clarify possible downstream effects on breastfeeding of one intrapartum drug, synthetic oxytocin.

Background synthetic oxytocin (synOT) is a manufactured product identical to endogenous oxytocin (OT). After being synthesized by Vincent du Vigneaud, who won the Nobel Prize in chemistry in 1955 in part for this work, Sandoz Pharmaceuticals made the commercial product available. Research studies using synOT were published in the following years and the drug became integrated into clinical practice as an induction and augmentation agent in labor (via continuous IV infusion), to reduce blood loss after birth (via IM injection), and to stimulate milk ejection (as a nasal spray).

Over time, synOT came to be understood not just as a drug to be administered in cases of obstetric crisis, but also as an elective management tool, useful in conforming women’s bodies to a predetermined timeline. The use of synOT in obstetrics integrated smoothly into the US. Post-World War II medicalized concept of birth and breastfeeding; it could make women’s non-compliant physiologic processes fit into an industrial model [7]. In this model, the clock and calendar are used to dictate the precise duration of pregnancy (the expected date the baby should be born, the due date”), the tolerable length of each stage of labor, the total number of allowable hours of labor, how long each breastfeeding should last, the number of breast feedings each day, how much time there should be in-between feedings and when weaning should occur.

The Institute for Safe Medication Practices (ISMP) has listed IV oxytocin (synOT) as one of the 12 medications most implicated in harmful errors in acute care hospitals [8]. According to a survey of liability cases, approximately 50% of paid liability claims affecting maternity services involve alleged misuse of oxytocin” [9]. In addition, synOT has received a Black Box” or Boxed” warning (the strongest caution the United States Food and Drug Administration (FDA) can give) which reads “Not for Elective Labor Induction: not indicated for elective labor induction since inadequate data to evaluate benefit vs. risk; elective induction defined as labor initiation without medical indications’ [10]. In spite of cautions, labor induction rates in the United States have been increasing since the early 1990s to 23.8% nationally [11], however in a study of 19 US. hospitals, the induction rate was reported to be 42.9% for first time mothers and 31.8% for multiparas [12]. The rate of synOT used for augmentation is estimated to be between 50 and 60% [13], with highest use in conjunction of an epidural for pain management. In addition, women in the United States are to be administered an IM injection of synOT after the baby is born if they do not have an IV in place, according to the Association of Women’s Health, Obstetric and Neonatal Nurses’ (AWHONN) guidelines [14], suggesting that there is a near universal exposure to synOT for birthing women in the United States.

The hormone oxytocin (from the Greek meaning swift birth”) has several functions beyond the obvious one: the mediation of uterine contractions. Oxytocin is predominantly produced in the hypothalamus, stored and secreted in a periodic bolus fashion [15] or pulses from the posterior pituitary. Oxytocin receptors (OTRs) are found on the smooth muscle cells in the uterus and the breast, where they work to contract the uterine muscles during labor and birth and the myoepithelial cells in the breast to eject milk. The central nervous system, including the spinal cord and the brain, also has OTRs; the hippocampal clusters of OTRs in the brain are thought to be integral in facilitating social learning, memory consolidation and bonding.


A prior study [16] demonstrated that synOT administration during labor was related to a decreased probability that the newborn would self-attach to the breast and suckle while in skin to skin contact with the mother within the first 60 minutes after birth when compared to non-synOT exposed neonates. Videotape analysis showed that the exposed neonates had significantly fewer minutes of rest.

In order to further understand these prior findings and to seek the physiological pathways affected by synOT related to breastfeeding, a modified ascending link tracing methodology was utilized. The ascending, link tracing method (also called chain referral” or snowball” method) has been primarily used in sociology to find hidden or elusive populations and has proven to be effective [17]. The technique involves finding one member of the population and seeking referral to others. In this case, the process was modified to begin with one research study (instead of one human member of a population) and snowball” to additional research studies using relevant references until saturation is reached. This method was chosen in the hope of capturing the widest possible range of physiologic pathways.

Beginning with one citation used in a prior study [18], relevant studies were linked by locating any cited references that could refer to physiologic pathways which might be affected by synOT or the physiologic relationship of synOT to breastfeeding. The references cited in the new article were accessed to continue the link tracing. The PubMed feature similar articles” for each article was also used to access the maximum possible number of articles. This referral linking process was continued until reaching saturation, when no new physiologic pathways with downstream breastfeeding implications were identified. The collection and analysis was performed between May 15 and November 13, 2017.


Three pathways related to physiologic effects on breastfeeding by synOT administration were identified: dysregulation of the maternal OT system, the crossing of the fetal blood brain barrier by synOT, and hyper stimulation of the uterus. Six downstream outcomes that could possibly affect breastfeeding include decreased maternal endogenous oxytocin, increased risk of negative neonatal outcomes, decreased neonatal rest during the first hour with the potential of decreasing the consolidation of memory, decreased neonatal pre-feeding cues, and decreased neonatal reflexes associated with breastfeeding, and in the long term, increased maternal OT levels possibly related to the observed increased risk of maternal depression, somatic symptoms and anxiety disorders. A cascade model was constructed in order to demonstrate the findings (Figure 1).

Citation: Cadwell K and Brimdyr K. Intrapartum Administration of Synthetic Oxytocin and Downstream Effects on Breastfeeding: Elucidating Physiologic Pathways. Ann Nurs Res Pract. 2017; 2(3): 1024.