Mother and newborn adaptations after birth : influence of administration of oxytocin and epidural analgesia during labour

Abstract

Aims: This thesis explores postpartum physiological and psychological adaptations in mothers and newborns in the short-and long-term perspective. The thesis further explores the influence of labour ward interventions, such as epidural analgesia (EDA) and exogenous administration of oxytocin on these adaptations.

Material and methods: An explorative longitudinal design was used. 72 healthy, non-smoking Swedish-speaking primiparae with a normal singleton pregnancy and birth and their healthy full term newborns were consecutively enrolled in the study. Mothers and newborns stayed together at the labour-and maternity wards and the newborns had been exclusively breastfed on demand. The mother-newborn dyads had been exposed to different labour ward routines: 1) mothers who had received intravenous oxytocin during labour (OT iv group, n=10), 2) mothers who had received oxytocin intramuscularly after birth to prevent postpartum haemorrhage but no other treatment (OT im group, n=15) and 3) mothers who had received EDA during labour (EDA group, n=24). 4) Mothers who had not received any form of oxytocin or EDA during labour (control group, n=23).

The EDA group was divided into two separate groups: EDA with (EDAOT group, n=17) or without oxytocin infusion (EDAnon-OT group, n=7). Data were collected two days postpartum in connection with a morning breastfeed. Maternal blood samples were drawn with an interval of 30 seconds during the first 7.5 minutes and at 10, 20, 30, and 60 minutes after start of suckling. These samples were analysed for oxytocin and prolactin using ELISA (I). Blood pressure was recorded by a wrist blood pressure monitor before and at 10, 30, and 60 minutes after start of breastfeeding. 33 mothers continued to measure their blood pressure once per week in connection with a breastfeed during a 6-month follow up (II). The women s personality profile was assessed at two days, two and six months postpartum by the Karolinska Scales of Personality (KSP) (III). The newborn interscapular skin temperature was recorded with an electronic thermometer before and at 5, 10, 20, and 30 minutes after start of the breastfeed (IV).

Results: Breastfeeding two days postpartum. Breastfeeding induced an immediate pulsatile release of oxytocin and prolactin levels rose significantly after 20 minutes. There was a positive correlation between oxytocin and prolactin levels (I). Maternal systolic and diastolic blood pressure fell during the breastfeed by 9 and 8 mmHg, respectively (II). At two days postpartum, according to the KSP, the maternal personality profile was changed towards reduced anxiety and aggression and increased socialisation when compared to a normative sample of women (III). The interscapular skin temperature of the newborns rose during the breastfeed (IV). Follow up study. Blood pressure fell in response to breastfeeding episodes and basal systolic and diastolic blood pressure fell by 15 and 10 mmHg, respectively, during the 6-month follow up period (II). KSP ratings showed that the breastfeeding women exhibited lower scores on anxiety and aggression and higher scores on socialisation at two and six months postpartum, when compared to the normative sample of women (III).

Medical interventions during labour. Median oxytocin levels were lower in the group of women having received EDA with oxytocin infusion (EDAOT group) than in the EDAnon-OT, OT iv and OT im groups. In addition, median oxytocin levels were decreased in a dose-dependent manner in women having received oxytocin infusion in connection with labour (OT iv and EDAOT groups). Prolactin levels did not rise in women belonging to the EDAnon-OT group, but rose more and at an earlier time point in mothers having received oxytocin infusion (OT iv and EDAOT groups) than in controls (I). The administration of EDA attenuated changes in the KSP towards less anxiety and more socialisation at two days post partum as seen in the control, OT iv, and OT im groups. At two and six months postpartum, however, the KSP scores of the EDA group had approached the KSP scores of the other groups. Exogenous oxytocin infusion (OT iv and EDAOT groups) dose-dependently reinforced the KSP changes in some anxiety and aggression subscales (III). Newborns to mothers who had received EDA during labour did not show a rise in interscapular skin temperature in response to breastfeeding, but the response was reinforced in newborns to mothers belonging to the OT iv group, when compared to controls (IV).

Conclusion: This study confirms the existence of physiological and psychological adaptations in breastfeeding mothers and their newborns in the short-and long-term perspective. Administration of exogenous oxytocin and EDA during labour influenced these adaptations.