ACOG Committee Opinion no. 597: Committee on Obstetric Practice: Labor induction or augmentation and autism

[Oxytocin as a neuroprotective strategy in neonates: concept and preclinical evidence]

OBJECTIVE

Prematurity and intra-uterine growth retardation are responsible for brain damage associated with various neurocognitive and behavioral disorders in more than 9 million children each year. Most pharmacological strategies aimed at preventing perinatal brain injury have not demonstrated substantial clinical benefits so far. In contrast, enrichment of the newborn's environment appears to have positive effects on brain structure and function, influences newborn hormonal responses, and has lasting neurobehavioral consequences during infancy and adulthood. Oxytocin (OT), a neuropeptide released by the hypothalamus, may represent the hormonal basis for these long-term effects.

METHOD

This review of the literature summarizes the knowledge concerning the effect of OT in the newborn and the preclinical data supporting its neuroprotective effect.

RESULTS

OT plays a role during the perinatal period, in parent-child attachment and in social behavior. Furthermore, preclinical studies strongly suggest that endogenous and synthetic OT is capable of regulating the inflammatory response of the central nervous system in response to situations of prematurity or more generally insults to the developing brain. The long-term effect of synthetic OT administration during labor is also discussed.

CONCLUSION

All the conceptual and experimental data converge to indicate that OT would be a promising candidate for neonatal neuroprotection, in particular through the regulation of neuroinflammation.

Oxytocin: physiology, pharmacology, and clinical application for labor management

Oxytocin is a peptide hormone that plays a key role in regulating the female reproductive system, including during labor and lactation. It is produced primarily in the hypothalamus and secreted by the posterior pituitary gland. Oxytocin can also be administered as a medication to initiate or augment uterine contractions. To study the effectiveness and safety of oxytocin, previous studies have randomized patients to low- and high-dose oxytocin infusion protocols either alone or as part of an active management of labor strategy along with other interventions. These randomized trials demonstrated that active management of labor and high-dose oxytocin regimens can shorten the length of labor and reduce the incidence of clinical chorioamnionitis. The safety of high-dose oxytocin regimens is also supported by no associated differences in fetal heart rate abnormalities, postpartum hemorrhage, low Apgar scores, neonatal intensive care unit admissions, and umbilical artery acidemia. Most studies reported no differences in the cesarean delivery rates with active management of labor or high-dose oxytocin regimens, thereby further validating its safety. Oxytocin does not have a predictable dose response, thus the pharmacologic effects and the amplitude and frequency of uterine contractions are used as physiological parameters for oxytocin infusion titration to achieve adequate contractions at appropriate intervals. Used in error, oxytocin can cause patient harm, highlighting the importance of precise administration using infusion pumps, institutional safety checklists, and trained nursing staff to closely monitor uterine activity and fetal heart rate changes. In this review, we summarize the physiology, pharmacology, infusion regimens, and associated risks of oxytocin.

An association of intrapartum synthetic oxytocin dosing and the odds of developing autism

A case-control study was performed to determine whether an association exists between exposure to synthetic oxytocin and a subsequent autism spectrum disorder diagnosis; 171 children under age 18 meeting Diagnostic and Statistical Manual of Mental Disorders (5th ed.) autism spectrum disorder criteria were compared to 171 children without autism spectrum disorder diagnosis matched by gender, birth year, gestational age, and maternal age at birth. A conditional logistic regression model was used to examine the association of clinical variables and autism spectrum disorder. Significantly elevated odds ratios for autism spectrum disorder were associated with first-time Cesarean section (odds ratio = 2.56), but not a repeat Cesarean section. Odds ratios were also significantly elevated for subjects whose mother’s body mass index was 35 or higher at birth (odds ratio = 2.34) and subjects in which the reason for delivery was categorized as “fetal indication” (odds ratio = 2.00). When controlling for these and other variables, the odds of developing autism spectrum disorder were significantly elevated in males with long duration of exposure (odds ratio = 3.48) and high cumulative dose of synthetic oxytocin (odds ratio = 2.79). No significant associations of synthetic oxytocin dosing and autism spectrum disorder were noted in female subjects. The association of elevated autism spectrum disorder odds found with high duration and high cumulative dose synthetic oxytocin in male subjects suggests the need for further investigation to fully elucidate any cause and effect relationship.

The oxytocin-CD38-vitamin A axis in pregnant women involves both hypothalamic and placental regulation

OBJECTIVE

Oxytocin, a hypothalamic hormone secreted upon release of ectoenzyme CD38, plays a vital role in interpersonal bonding behaviors. Reduced plasma oxytocin characterizes autistic individuals. CD38 levels, which were found to be low in LBCs derived from autistic patients, is upregulated upon the addition of a vitamin A derivative. During pregnancy, oxytocin is also secreted by placenta. Recent controversial studies have suggested an increased risk for autism when oxytocin is used during induction and augmentation of labor. We aimed to examine the tripartite relationship between oxytocin, CD38 and vitamin A in pregnant women and their newborns.

METHODS

Thirty-one healthy expectant mothers were enlisted for this study. Levels of oxytocin, CD38 and ATRA were measured in both maternal peripheral and newborn cord blood, and the tripartite relationship between these parameters examined. Estrogen and progesterone levels of the mothers were also recorded. Several clinical measures were also noted.

RESULTS

Mean maternal oxytocin and vitamin A levels were approximately 8- and 4-fold higher, respectively, than neonatal levels. CD38 expression, however, was 9 times higher in neonates than in the maternal group. Positive correlation was found between maternal and cord blood for both oxytocin and CD38.

CONCLUSIONS

This establishment of normative values for oxytocin, CD38 and vitamin A in healthy pregnant women and newborns may serve as a reference in the investigation of developing pathologies of disorders such as autism.