When it comes to early elective C-sections, there are many harmful effects on the fetal-newborn transition, and the implications for care of the mother-newborn dyad are far-reaching, says retired neonatologist Professor Suzanne Delport.
Newborns are increasingly being delivered by C-section before their expected date of delivery. This scenario is particularly common in the South African private sector with around 80% and more of newborns being delivered in this way. It is concerning that these infants have not been exposed to labour, as this puts them in a vulnerable position for a complicated fetal-newborn transition and adaptation to extra-uterine existence. The fetal-newborn transition remains the most profound physiological feat in human life and should be approached with the respect that it deserves.
Midwives, nurses and paediatricians who manage these infants after birth should anticipate complications related to extra-uterine adaptation and parallel this anticipation with a policy of increased vigilance and surveillance. Even though the infant may seem robust as judged by the birth weight, an element of immaturity prevails because exposure to labour was absent. This is in stark contrast to a normal vaginal delivery where the mother and newborn infant are healthy and can fend for themselves immediately after the birthing process. Attachment and suckling occur effortlessly in most instances and the mother-infant dyad becomes a self-sustaining unit.
An early elective caesarean delivery, on the other hand, which bypasses the natural birth process and the intra-uterine physiological preparation which precedes it, places more responsibility on healthcare personnel because the mother-newborn dyad is prone to a prolonged recovery: the mother from major surgery and the infant from ‘iatrogenic prematurity’ because of an early elective delivery by caesarean section.
In a normal pregnancy, the unborn baby initiates labour at the point of organ maturity. Although the precise physiologic stimulus which heralds the end of pregnancy and the initiation of labour remains elusive, cortisol has been identified as being the most important hormone that drives the secretion of the catecholamines comprising the flight-or-fight reaction of birth. Cortisol is secreted by the fetal adrenal gland and starts to increase at around 30 weeks of gestation. The concentration increases three-fold by the end of pregnancy and another five-fold during labour. The most important effect of cortisol is to convert a system in anticipation of birth from one meeting the needs of fetal life, to a system meeting the needs of extra-uterine life, and as such to facilitate a seamless fetal-newborn transition and survival.
An elective C-section denies the unborn baby the final cortisol and catecholamine surges associated with labour. These hormonal surges are essential for the final prenatal adaptation of organs and enzymes before delivery and in their absence, oxygenation, temperature regulation, glucose production, suckling and attachment do not fall into place at the very moment of birth, with potential life-threatening consequences.
The unborn baby’s lungs are not vital organs and as such are under-perfused. Blood is oxygenated in the placenta and reaches the fetal vital organs such as the brain and heart via several shunts (e.g. ductus arteriosus). Fluid in the fetal lungs is secreted by the lung epithelium and fulfils an essential role in lung development. In anticipation of delivery, and before labour, a shift from fluid secretion to fluid absorption starts to occur. This process, which is facilitated by cortisol and catecholamines, reaches completion during labour and enhances adaptation to air-breathing after birth.
Following the first breaths after birth, more oxygen enters the blood, which stimulates dilation of the pulmonary arteries and blood flow to the lungs increases. Oxygenation can now occur in the lungs because fluid has been cleared during labour and vasodilation of the pulmonary arteries has been achieved. This dilation, however, opens up a vascular space that had been a potential space in the unborn baby and must now be perfused with blood from the placenta via the umbilical vein. This process is facilitated by means of delayed cord clamping. It stands to reason that in the absence of labour and delayed cord clamping, the lungs of the newborn infant are fluid-filled and under-perfused.
The clinical presentation is that of an infant who has a fast breathing rate and needs supplemental oxygen. The cause for respiratory maladaptation may be:
- Transient tachypnea of the newborn (TTN)
- Respiratory distress of the newborn (RDN) because of a surfactant deficiency
- Persistent pulmonary hypertension of the newborn (PPHN)
- A combination of all three conditions
A normal fetus becomes an ill newborn because of an iatrogenic intervention (early elective C-section), and admission to a specialised neonatal unit for respiratory support becomes mandatory.
At birth the oxygen saturation of every baby should be measured by pulse oximetry (SpO2) in the right arm (preductal) and documented, in combination with the pattern of breathing and respiratory rate after birth. From a preductal SpO2 of 60% at one minute, an increase to 85%–95% at 10 minutes should occur. At this time documentation of a successful transition relating to oxygenation and respiratory function can be made if the respiratory rate (non-crying) is 50–60 breaths per minute, no evidence of accessory respiratory muscle activity is present and the SpO2 is ≥95% without supplemental oxygen. These observations should be repeated at regular intervals during the first 24 hours of life to confirm that adaptation has indeed been successful, since a deterioration may still occur.
The fetal temperature is maintained at 0.5⁰C higher than the mother. Heat is generated by fetal metabolism, the uterus and placenta. Brown adipose tissue starts to appear at 29 weeks and increases throughout the third trimester but is metabolically inactive in utero. At birth, the metabolism of brown adipose becomes active and facilitates heat production. Increased sympathetic activity during labour releases catecholamines within the brown adipose tissue and produces heat via non-shivering thermogenesis. Hypothermia can lead to hypoxaemia and hypoglycaemia and is thus a potential life-threatening complication. Its occurrence should be prevented at all costs.
Infants born by a pre-labour elective C-section are prone to hypothermia for the following reasons:
- The ambient temperature of an operating theatre is often <26⁰C and therefore colder than a delivery room. Maternal hypothermia before delivery occurs commonly, which has a cooling effect on the unborn baby.
- The newborn is exposed to the low ambient temperature of the operating theatre after birth
- Skin-to-skin contact immediately after birth may lead to further heat loss due to conduction, should the mother be hypothermic.
- Brown adipose tissue is decreased in infants delivered before the expected date of delivery.
- Non-exposure to labour leads to a blunted activity of the sympathetic nervous system and suboptimal stimulation of the metabolic activity in the brown adipose tissue leading to heat production.
Meticulous monitoring of the temperature of an infant after an elective C-section is of the essence to diagnose and manage hypothermia early and effectively.
Blood glucose homeostasis
Transfer of nutrients occurs by diffusion from the placenta to the unborn baby. Glucose is the most important fetal energy source and stimulates insulin secretion by the fetal pancreas, which induces lipogenesis. Glucose meets the metabolic needs of the unborn baby and a certain amount is converted to glycogen and stored in the liver as well as in cardiac and skeletal muscle.
At birth, the glucose and nutrient supply from the mother ceases abruptly. As expected, the blood glucose level in the newborn drops after birth, reaching a nadir around one hour after birth. Normal adaptation facilitates a rapid response with a steady rate of glucose production at 4–6mg/kg/min, related to a glycogen surge resulting from sympathetic stimulation and catecholamine release in response to the cortisol surge associated with labour. Glucose production is sustained by glycogenolysis and glyconeogenesis (production of glucose from lactate and amino acids). Early initiation of breastfeeding stabilises the blood glucose level in the majority of healthy newborns.
In the event of a pre-labour delivery by C-section, a cortisol surge induced by labour is absent before birth. Continuous endogenous glucose production is ineffective and the risk for hypoglycaemia increases. Glucose monitoring is of the essence in order to diagnose and treat hypoglycaemia timeously.
Attachment and breastfeeding
After a vaginal delivery, the newborn is alert because of the surge of catecholamines during labour. This facilitates a strong sucking reflex and effective suckling immediately after birth, which are essential for the initiation of successful short- and long-term lactation, as well as attachment. Maternal oxytocin secretion, which was initiated during labour, is continued during suckling to facilitate the let-down reflex and the contraction of the uterus.
Hormonal effects are absent in a pre-labour elective C-section. The unborn baby is ‘taken by surprise’ because labour did not ‘alert’ the fetus. If the delivery is scheduled before full term (39–40 weeks), immaturity may complicate adaptation, disempowering the newborn from suckling effectively because of an immature sucking reflex. The mother – on the other hand – is recovering from major surgery and is not roomed in with her infant immediately after birth. Valuable time for attachment and breastfeeding is lost during this sensitive period because of separation. At this time, nursing personnel must be highly diligent in assisting with breastfeeding. Discharge of the mother-newborn dyad should be delayed until such time that breastfeeding is well established and the mother is confident.
Transition to motherhood
Endogenous oxytocin is a neuroendocrine hormone that rises dramatically during and after a normal birth as an adaptive response in the transition to motherhood. An important effect of endogenous oxytocin is to buffer maternal stress reactivity during the perinatal period – a time which is characterised by intense stress. It supports a positive mood and regulates healthy mothering behaviour such as bonding, synchronicity in mother-newborn interaction, lactation and breastfeeding.
A depressed mood suppresses positive mothering behaviour and impacts negatively on the quality of the mother-infant interaction, which places babies at risk for a poor neurodevelopmental outcome.
Labour may be augmented with synthetic oxytocin as part of modern obstetrics. The effect of this substance on the levels of endogenous oxytocin is of concern and is currently being investigated. Preliminary results show that synthetic oxytocin depresses the levels of endogenous oxytocin in some scenarios such as epidural analgesia. Maternal consequences may result that last beyond the birth experience. Until such time that definitive evidence is available, healthcare workers should maintain a policy of minimal interference in the biologically regulated process of childbirth.
Healthcare personnel should be aware of the postnatal negative effects of a pre-labour early elective C-section on the mother-newborn dyad. Complications such as respiratory distress, hypothermia, hypoglycaemia and feeding difficulties should be anticipated in the newborn infant. Continual support should be rendered to the mother since difficulties with transition to motherhood may have a negative impact on attachment and lactation, and ultimately on the neurodevelopmental outcome of the newborn.
Professor Suzanne Delport is a retired neonatologist, but she is probably busier now than when she was in fulltime employment! Prof Delport worked at Kalafong Hospital in conjunction with the University of Pretoria for most of her illustrious career. She has a particular interest in the wellbeing of the mother-infant dyad during the perinatal period, and is a very strong breastfeeding supporter.
This article was originally published in Sensitive Midwifery Magazine in October 2016.
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