The effect of antenatal steroid treatment on fetal autonomic heart rate regulation revealed by fetal magnetocardiography (fMCG)

Maternal cortisol during pregnancy is related to infant cardiac vagal control

“…Greater exposure to maternal cortisol during gestation may reduce infant ability to develop the physiological reserve capacity that is needed to regulate responses to physical and social environments; and this reduced capacity may help to explain the association between lower basal CVC and reduced socio-emotional competence (Liew et al, 2011) and effortful control of attention (Taylor et al, 2015) in children with elevated cortisol exposure. These results are also consistent with previous reports of an inverse association between exposure to synthetic glucocorticoids in utero and fetal basal CVC (Lunshof et al, 2005;Schneider et al, 2010;Senat et al, 1998). Our findings suggest that the effects of exogenous glucocorticoids on fetal CVC are similar to the effects of endogenous maternal cortisol on infant CVC.…”

“…Fetal CVC was reduced following the administration of betamethasone delivered during the third trimester to 8 pregnant mothers at risk of preterm labor (Schneider et al, 2010). Further, shortterm variability in fetal HR increased transiently after the administration of betamethasone followed by a significant reduction that spanned 2-7 days (Lunshof et al, 2005;Senat et al, 1998).…”

The Influence of Corticosteroids on Fetal Heart Rate Variability

“…As shown in Table 3, a decrease in mfHR was found after betamethasone administration on day 1 in 8 of the included studies, 15,21Y27 of which 7 showed a significant result. However, this effect was relatively small, with a 3% to 5% decrease in mfHR.…”

“…Therefore, fHR is the primary variable for controlling cardiac stability and is primarily regulated by the ANS. 15 It is known that fHRV is a reliable marker of fetal well-being. 16,17 In 1963, Hon and Lee 18 observed that, in cases of fetal distress, changes in beat-to-beat heart rate interval occur before changes in heart rate itself.…”

Antenatal corticosteroids for fetal lung maturation in threatened preterm delivery: indications and administration

“…Fetal heart rate as determined by cardiotocography shows marked reduction of variability, 2-3 days after betamethasone administration. These changes are thought to due to a shift in the sympatho-vagal balance [27]. Similarly, fetal body movements and breathing activity are reduced.…”