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  • Writer's pictureEmma Armstrong

Hormones: Catecholamines


  • The fight-or-flight hormones adrenaline and noradrenaline (epinephrine and norepinephrine in US literature) are part of the group of hormones known as catecholamines (CAs) and are produced by the body in response to stresses such as hunger, fear, and cold, as well as excitement. Together they stimulate the sympathetic nervous system for fight or flight. (AIMS)

  • During labour, maternal CA levels slowly and gradually rise, peaking around transition. However, high adrenaline levels in early labour, which reflect activation of the woman's fight-or-flight system in response to fear or a perception of danger, have been shown to inhibit uterine contractions, therefore slowing or even stopping labour. Noradrenaline also acts to reduce blood flow to the uterus and placenta and therefore to the baby. (AIMS)

  • After the birth, the new mother's CA levels drop steeply. If she is not helped to warm up, the cold-related stress will keep her CA levels high, which will inhibit her uterine contractions and therefore increase her risk of postpartum haemorrhage. (AIMS).

  • In the late-labour stage if you perceive danger or stress, they may paradoxically stimulate contractions so you give birth more quickly. A rise in epinephrine when you’re in the later stages of labour increases your levels of prostaglandin and cortisol to help with contractions. This will make you feel a sudden rush of energy and will cause several strong contractions and will help you push.(NCT)

Too much adrenaline can cause problems in labor and birth by:

  • Causing distress to the baby before birth.

Causing contractions to stop, slow or have an erratic pattern, and lengthening labor.

  • -Creating a sense of panic and increasing pain in the mother.

  • Leading health care providers to respond to these problems with cesarean surgery and other interventions.

You can keep adrenaline down during labor and birth by:

  • Staying calm, comfortable and relaxed.

  • Being informed and prepared.

  • Having trust and confidence in your body and your capabilities as a woman.

  • Having trust and confidence in your care providers and birth setting.

  • Being in a calm, peaceful and private environment and avoiding conflict.

  • Being with people who can provide comfort measures, good information, positive words and other support.

  • Avoiding intrusive, painful, disruptive procedures.


  • For the baby also, labour is an exciting and stressful event, reflected in increasing CA levels. In labour these hormones have a very beneficial effect, protecting the baby from the effects of hypoxia (lack of oxygen) and subsequent acidosis by redistributing cardiac output (blood supply) and by increasing the capacity for anaerobic glycolysis (metabolism of glucose at low oxygen levels). (AIMS)

  • The baby experiences a marked surge in CA hormones, especially noradrenaline, close to the time of birth, probably triggered by pressure on the head. This surge plays a very important role in the baby's adaptation to extrauterine life. It aids newborn metabolism by increasing levels of glucose and free fatty acids, which protect the newborn's brain from the low blood sugar that can occur in the early newborn period when the baby loses the placental supplies of glucose.(AIMS).

  • Early in second stage, when the cervix is fully open but the urge to push is not yet strong, a woman can feel the need to rest for some time. This is sometimes known as the “rest and be thankful” time. After this, she may quite suddenly experience the dry mouth, dilated pupils and sudden burst of energy that are all characteristic of high levels of CAs. This burst of CA gives a mother the energy to to push her baby out. (SBuckley)


-Catecholamines enhance respiratory adaptation to life outside the womb by increasing the absorption of amniotic fluid from the lungs and stimulating surfactant release. Surfactant is essential for smooth inflation of the newborn lungs. CAs also assist with the necessary newborn shift to nonshivering thermogenesis (heat production), increase cardiac contractility, stimulate breathing, and enhance responsiveness and tone in the newborn. (AIMS).

  • High CA levels at birth also ensure that the baby is wide-eyed and alert at first contact with the mother. The baby's CA levels also drop steeply after an undisturbed birth, being soothed by contact with the mother, but noradrenaline levels remain elevated above normal for the first twelve hours. High newborn noradrenaline levels, triggered by a normal birth, have been shown to enhance olfactory learning during this period, helping the newborn to learn the mother's smell. (AIMS)

  • CA levels drop quickly after the birth, which can make a mother may feel cold or shaky. (SBuckley)

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