Causes and Consequences of Maternal and Fetal Sympathoadrenal Activation During Parturition

Abstract

The sympathoadrenal system is activated in both the mother and fetus during parturition. The fetal plasma catecholamines may reach extremely high levels during deliveries complicated by asphyxia.Increased maternal sympathoadrenal activity during labour or caesarean section may negatively affect uteroplacental blood flow with possible adverse effects on the fetus. Such an increase may be avoided by adequate maternal pain relief and by the sympathetic blockade which follows epidural anaesthesia.Fetal sympathoadrenal activation during parturition seems on the contrary to be of positive functional importance both for fetal circulatory regulation in utero a well as for the neonatal adaptation in terms of pulmonary function and metabolic stimulation.

Effects of labor contractions on catecholamine release and breathing frequency in newborn rats.

“…These changes include pulmonary and respiratory variables (Cohen & Carson, 1985;Faxelius et al, 1983;Irestedt et al, 1984;Levine et al, 2001;van den Berg et al, 2001;Zanardo et al, 2004), blood flow (C. T. Jones, 1980;Irestedt et al, 1984), resistance to oxidative stress (Buhimschi et al, 2003), neonatal neurological condition (Otamiri et al, 1990(Otamiri et al, , 1991, and complex global electroencephalogram patterns (Kim et al, 2003). Perinatal olfactory cues guide breast preferences (Varendi, Porter, & Winberg, 1994), and learning about olfactory cues is enhanced in neonates that experience labor contractions, possibly mediated by norepinephrine (Varendi, Porter, & Winberg, 2002).…”

“…Apparently, the birth-related catecholamine surge confers upon newborns a number of important protections. As compared with babies exposed to a trial of labor, babies delivered by elective cesarean section (even near term) show (a) an increased risk of respiratory morbidity (Cohen & Carson, 1985;Zanardo et al, 2004); (b) a fivefold increase in the likelihood of persistent pulmonary hypertension (Levine, Ghai, Barton, & Strom, 2001); (c) lower dynamic lung compliance (Faxelius, Hagnevik, Lagercrantz, Lundell, & Irestedt, 1983) and higher functional residual capacity, possibly as an adaptation to elevated lung water content (Hagnevik, Lagercrantz, & Sjoqvist, 1991); (d) increased incidence of postpartum respiratory distress (Irestedt, Lagercrantz, & Belfrage, 1984); (e) decreased protection from oxidative stress (Buhimschi, Buhimschi, Pupkin, & Weiner, 2003); and (f) delayed neurodevelopmental status (Otamiri, Berg, Ledin, Leijon, & Lagercrantz, 1991;Otamiri, Berg, Ledin, Leijon, & Nilsson, 1990). Animal studies of labor's effects on the fetus and newborn, conducted almost exclusively in the precocial sheep fetus, have revealed important roles of birth-related catecholamines, including stimulating lung liquid absorption (reviewed by Barker & Olver, 2002), sustaining metabolic and cardiac homeostasis (Padbury et al, 1987), and providing protection from hypoxia (C. T. Jones, 1980).…”

Fetal catecholamines and the Apgar score

“…The catecholamines increase every component of the Apgar score except skin color. The heart rate is augmented, respiration is stimulated as well as reflex irritability and muscle tone [4]. In order to further elucidate the association between fetal catecholamines, fetal pH and Apgar score the present investigation was initiated.…”

Intravenous patient-controlled analgesia with remifentanil in early labour

“…This may therefore have a profound effect on the neonate in case of a very short delay from the last maternal dose to delivery. A strong exposure to opioids could also blunt the foetal sympathoadrenal activation associated with vaginal delivery which has been suggested as an important factor in respiratory adaptation in the neonate (Irestedt et al 1984).…”