Pathogenesis of oxytocin-induced neonatal hyperbilirubinaemia

Clinical Experiences and Mechanism of Action with the Use of Oxytocin Injection at Parturition in Domestic Animals: Effect on the Myometrium and Fetuses

Oxytocin is a key hormone for parturition and maternal traits in animals. During the peripartum period, the levels of endogenous oxytocin dictate physiological events such as myometrial contractions, prostaglandin production with the subsequent increase in oxytocin receptors, and the promotion of lactation when administered immediately after birth. While this hormone has some benefits regarding these aspects, the exogenous administration of oxytocin has been shown to have detrimental effects on the fetus, such as asphyxia, meconium staining, ruptured umbilical cords, and more dystocia cases in females. This review aims to analyze the main effects of oxytocin on myometrial activity during parturition, and its potential favorable and negative administration effects reflected in the fetus health of domestic animals. In conclusion, it is convenient to know oxytocin's different effects as well as the adequate doses and the proper moment to administrate it, as it can reduce labor duration, but it can also increase dystocia.

Factors associated with extreme hyperbilirubinaemia in neonates at the University Hospital of the West Indies

AIM

To determine factors associated with extreme hyperbilirubinaemia in neonates at the University Hospital of the West Indies.

METHODS

A retrospective review of all neonates with hyperbilirubinaemia requiring medical intervention at the University Hospital of the West Indies between 1 January 2006 and 30 June 2007 was performed. Factors associated with extreme hyperbilirubinaemia were determined using multiple logistic regression models.

RESULTS

A total of 170 neonates fulfilled the inclusion criteria for the study and 15 (9%) of them had extreme hyperbilirubinaemia. The majority (97, 57%) were term infants and 103 (61%) were male. Exclusively breastfed neonates were more likely to have extreme hyperbilirubinaemia (OR 2.6, 95% CI 0.01-0.6). Neonates whose mothers received oxytocin during labour (OR 2.7, 95% CI 0.02-0.3) and those who were G6PD-deficient (OR 2.6, 95% CI 0.01-0.5) were more likely to have extreme hyperbilurubinaemia.

CONCLUSION

Exclusive breastfeeding, oxytocin use in the mother during labour and G6PD deficiency in the infant were found to be factors associated with extreme hyperbilirubinaemia.

¿Pinzamiento precoz o tardío del cordón umbilical? Una revisión sistemática de la literatura médica

INTRODUCTION

There is wide variability in clinical practice in the moment of clamping the umbilical cord. Opinions in the medical community differ on the harm and/or benefits, both for the mother and for the newborn, of early versus late cord clamping. Currently, the debate among those who defend and/or criticize one or other of these practices continues. The aim of this study was to evaluate the effects of early versus late clamping of the umbilical cord in full-term newborns on maternal and neonatal outcomes.

MATERIAL AND METHODS

A literature search of randomized clinical trials was carried out in the Cochrane Library, MEDLINE and Lilacs. It was completed with a hand search of references in relevant articles. All randomized controlled clinical trials of good methodological quality that compared early versus late cord clamping in term newborns were selected.

RESULTS

Of seven identified studies, four had the required characteristics for inclusion in this systematic review. Comparison of early versus late clamping in these studies revealed that late clamping could diminish the prevalence of children with low iron reserves at 3 months of age by 50%, but this result comes from a study that lost more than 40% of the patients during follow-up. The results concerning anemia at 3 months of age showed statistical heterogeneity since the two studies that analyzed this outcome had opposite results. For other outcomes such as birth weight, Apgar < 5, and tachypnea the studies were too small for significant differences to be detected.

CONCLUSIONS

This review shows that there is no clear evidence for defending any of the modalities of cord clamping in full-term newborns. Further research is needed to identify the best moment for cord clamping.

Could oxytocin administration during labor contribute to autism and related behavioral disorders?--A look at the literature

This literature review summarizes recent potential evidence, most of which is at the molecular/mechanistic level, in support of Hollander's hypothesis that excess oxytocin (OT), possibly through OT administration at birth, could contribute to the development of autistic spectrum disorders and related syndromes by proposed down regulation of the OT receptor (OTR). In this review, recent molecular evidence for OTR internalization by excess OT is related to OT's reported effects on animal social behavior, favoring social bondage, notably in sheep, voles, rats and especially mice. Adding indications for OT's capability of crossing the maternal placenta and OT's possibility of crossing an underdeveloped or stressed infantile blood brain barrier at birth, a causal connection between OT excess and behavioral disorders such as autism can be supported from a molecular perspective. Possible strategies such as a thorough statistical analysis of numerous birth records as well as molecular studies such as radiotracing using labeled OT are proposed to test this hypothesis.

Pulsatile oxytocin for induction of labor: a randomized prospective controlled study

In a prospective randomized study, 20 patients with term pregnancies underwent induction of labor with either continuous or pulsed (every 8 minutes) intravenous oxytocin infusion. There were no significant differences with respect to induction-labor interval, induction-delivery interval, cesarean section rates, need for pain relief and Apgar scores. Sixty percent of patients receiving continuous oxytocin infusion developed uterine hyperstimulation but only 10% receiving pulsed oxytocin did so. However, the difference was not significant. The mean +/- SEM total amount of oxytocin given by continuous infusion was 4237 +/- 1066 mU which was 70% more than by pulsatile infusion (2454 +/- 808 mU). The highest rate of oxytocin infused was significantly lower by pulsatile administration (5.2 +/- 0.8 mU/min) than by continuous infusion (9.2 +/- 1.8 mU/min, p = less than 0.05). Our study demonstrates that pulsed administration of oxytocin every 8 minutes is as effective and safe as continuous intravenous infusion of oxytocin for induction of labor, requires less oxytocin with therefore, a wider margin of safety and is consistent with the pulsatile release of oxytocin during normal labor.

'Idiopathic' jaundice in Sardinian full-term newborn infants: a multivariate study

'Idiopathic' hyperbilirubinaemia in the first 4 days of life was studied in 431 unselected healthy full-term (gestational age > or = 37 weeks) singleton Sardinian infants with birthweight > or = 2500 g. All infants were free from malformations or any disease requiring treatment other than jaundice, they were ABO and Rh compatible with their mothers and were not G6PD deficient. The serum bilirubin level was > 11.9 mg/dl (204 mumol/l) and > 14.9 mg/dl (256 mumol/l) in 37.1% and 15.3% of the study subjects. The vast majority of the infants (94%) were breast fed; no difference in the incidence of jaundice was found between breast-fed and bottle-fed infants. A logistic regression analysis indicated that high alpha-fetoprotein concentrations in cord blood, history of neonatal jaundice in previous full-term siblings, delayed first meconium passage and weight loss were associated with jaundice, defined as a serum bilirubin level > 11.9 mg/dl. These results suggest that the high rate of neonatal hyperbilirubinaemia in Sardinia is mostly related to constitutional and possibly hereditary factors.

A study of the relationship between the delivery to cord clamping interval and the time of cord separation. Oxford Midwives Research Group

A randomised controlled trial of 554 women was carried out to compare the effects of late and early umbilical cord clamping on the time of cord separation. In addition data were collected on maternal and neonatal outcomes. There were no significant differences between the two groups in the duration of cord adherence and neonatal and maternal outcomes. There appeared to be a higher rate of jaundice in the late clamped group which did not reach statistical significance. There was an unexpectedly higher rate of breast feeding at home in the late clamped group which did reach statistical significance. Overall the trial provides no clear evidence for the benefit of early cord clamping (the current policy as part of the active management of the third stage in the UK) on the outcomes considered.

Oxytocin induction of labour: hyponatraemia and neonatal jaundice

To determine the effects of fluid restriction in induced labour with oxytocin in 5% dextrose solution, maternal venous blood and fetal cord venous blood were examined in 164 mothers in induced labour and 29 mothers with a spontaneous onset of labour. After satisfactory uterine activity was induced either the oxytocin infusion was managed according to routine delivery unit practice (n = 36), or infusion rates were halved (n = 45), or quartered (n = 43), or discontinued (n = 40). Despite fluid restriction during labour the mean sodium concentration in maternal blood or cord blood had fallen to a similar extent in all four induced groups at delivery. Potassium, urea, creatinine, total protein, and albumin in maternal blood or cord blood were affected differently by induced labour as compared with sodium. The fall in sodium concentration in maternal blood was a more consistent reflection of the total volume of fluid received, mean infusion rates and cord blood sodium after infusion rates were quartered or discontinued. The incidence of hyponatraemia was 5% in mothers and 8% in infants. A comparison of hyponatraemic and normonatraemic cord blood showed no significant differences in serum bilirubin levels or red cell counts, but more hyponatraemic infants developed neonatal jaundice. It is suggested that in induced labour fluid restriction alone does not prevent hyponatraemia and neonatal jaundice.

Intrapartum infusion of aqueous glucose solution, transplacental hyponatraemia and risk of neonatal jaundice

Cord serum sodium levels in three groups of 278 singleton infants, born vaginally at term, were correlated with the incidence of jaundice (serum bilirubin greater than or equal to 85 mumol/1) in the first 3 days of life. Of the 278 infants, 87 were born to mothers who were given infusions of 5% or 10% glucose in water during labour (group I), 90 were born to mothers who received glucose solution as a vehicle for oxytocin (group II), and 101 to mothers who did not receive any intravenous fluid therapy (control group). Jaundice was seen significantly more frequently in groups I (28/87, 32%) and II infants (30/90, 33%) than in the control group (12/101, 12%) (P less than 0.01), but when analysed in relation to cord serum sodium levels, the prevalence of jaundice in the normonatraemic infants (serum sodium greater than or equal to 131 mmol/1) was similar in the three groups. On the other hand, in groups I and II jaundice occurred about 3.5 times more frequently in the hyponatraemic infants [group I (17/32, 53%) and II (20/39, 51%)] than in the normonatraemic infants (P less than 0.01). The difference was not associated with any other perinatal or neonatal characteristic.

Neonatal jaundice after labour induced or stimulated by prostaglandin E2 or oxytocin

In a prospective study of neonatal jaundice 739 infants, delivered vaginally, in the vertex presentation, and without major complications, were examined. Labour was induced or stimulated after random allocation of the mothers to one of three oxytocics (prostaglandin E2 orally, oxytocin intravenously, or demoxytocin buccally). Oxytocics were unnecessary after primary amniotomy in 91 women. A linear logistic statistical analysis showed that gestational age has a highly significant influence on the risk of jaundice (defined by maximum serum level of bilirubin greater than or equal to 205 mumol/l). An apparent influence of birthweight could be explained by the correlation between birthweight and gestational age. The influence of the three oxytocic agents was not significant, although they may have had a slight effect; however, any such effect could be a consequence of the infants of mothers given oxytocics being less mature than those whom mothers did not receive oxytocics. The duration of labour and the mother's age also had no effect on risk of jaundice. Thus, neonatal jaundice after induced and stimulated labour seems to be primarily associated with fetal maturity; the pharmacological side-effect, if any, of oxytocics is of no importance.