Before we discuss how modern medical interventions like epidurals and synthetic oxytocin (Pitocin) can interfere with undisturbed birth, we need to understand the hormones of birth.
The natural regulation of hormone balance is an exceedingly sophisticated and complex process. And although we know the basics of how hormone regulation works, there is still much we don’t understand.
I’ve argued against using supplemental hormones to as a first step in treating hormone imbalances for exactly this reason. Whenever we take hormones, we run the risk of disrupting the delicate negative feedback system that regulates our own internal production of these hormones.
The image that comes to mind is a monkey in the cockpit of the space shuttle pushing a bunch of buttons.
Perhaps that’s an exaggeration, but the point is that any intervention that risks disrupting natural hormone balance and regulation is apt to cause problems. And there’s no time that’s more true than during pregnancy and childbirth.
The hormones of birth
The hormones of birth include estrogen and progesterone, oxytocin, beta-endorphins, prolactin and catecholamines (epinephrine/adrenaline and norepinephrine/noradrenaline).
Estrogen and progesterone
Estrogen and progesterone are the main hormones involved in “setting the scene” for birth, including activating, inhibiting and reorganizing other hormone systems. They both play a crucial role in the initiation of labor. For example, the placental production of estriol increases by more than 1,000 times close to the onset of labor, and progesterone production increases 10-18 times higher.
Estrogen has also been shown to increase the number of uterine oxytocin receptors and gap junctions in late pregnancy, which is thought to prepare the uterus for contractions in labor.
Oxytocin is the hormone associated with the contractions of labor and birth in all mammalian species. It has also been referred to as the hormone of love because of its involvement with sexual activity, orgasm, birth and breastfeeding.
In the context of undisturbed birth, Odent refers to oxytocin as the hormone of “forgetting oneself”.1 This is crucial because a fundamental aspect of an undisturbed birth is the sensation of an altered state of consciousness: “being transported” or “going to another world”.
Oxytocin is stored in the anterior pituitary and released in pulses every 3-5 minutes during early labor, becoming more frequent as labor progresses. Keep this in mind when we discuss the differences between natural oxytocin and synthetic oxytocin (Pitocin) used to induce labor in hospitals.
Current research suggests that oxytocin is the initiator of the rhythmic contractions of early labor, while prostaglandins produced locally in the uterus assume that role later in labor.
Some recent studies have found that oxytocin produced by the fetus may directly stimulate the mother’s uterine muscle, suggesting that the baby may be responsible for initiating labor.
Finally, oxytocin plays several important roles after birth. High levels of oxytocin produced as the baby stimulates the mother’s breast help keep the uterus contracted and prevent postpartum hemorrhage. Oxytocin mediates the “milk ejection reflex” which allows for successful breastfeeding. And, as the hormone of love, oxytocin promotes the development of a strong bond between mother and baby.
Beta-endorphin is a naturally occurring opiate that acts to restore homeostasis (internal balance). It is secreted by the pituitary gland in times of pain and stress. It activates the mesocorticolimbic dopamine reward system and produces pleasure in association with sex, birth and breastfeeding.
Studies suggest beta-endorphin increases tolerance to pain and suppresses the immune system, both of which are important during birth.
Beta-endorphin is similar to the addictive opiates morphine and heroin in that it induces feelings of pleasure, euphoria and dependency. Beta-endorphin levels during labor reach similar levels to those found in male endurance athletes during maximal exercise on a treadmill.
High levels of beta-endorphin help the mother to tolerate the pain of labor and nudge the her into the altered state of consciousness that characterizes an undisturbed birth. After the baby has been born, beta-endorphin (like oxytocin) reinforces the mother-infant bond and contributes to ecstatic feelings for both.
Finally, beta-endorphin promotes the release of prolactin during labor, which prepares the mother’s breast for lactation and aids in lung maturation for the baby.
Prolactin is known as the mothering hormone. It’s released by the pituitary during pregnancy and lactation, and it prepares a pregnant woman’s breasts for lactation.
During breastfeeding, prolactin levels influence sucking intensity, duration and frequency. Researchers believe prolactin (together with oxytocin) is responsible for the elevation of mood and feeling of calm mothers experience after breastfeeding.
Prolactin is also believed to play an important role in maternal behavior after birth via its effect on the nursing mother’s brain. It has been referred to as the hormone of “submission” or “surrender”. In the breastfeeding relationship, it may encourage the mother to put her baby’s needs before her own.
According to Sarah Buckley, M.D.2:
There are more than three hundred known bodily effects of prolactin, including induction of maternal behavior, increase in appetite and food intake, suppression of fertility, stimulation of motor and grooming activity, reduction of the stress response, stimulation of oxytocin secretion and opioid activity, alteration of the sleep-wake cycle and increase in REM sleep, reduction of body temperature, and pain relief. Prolactin, along with growth hormone, is one of the hormones of growth and lactation and as such has a crucial influence in the development and function of the immune system.
And those are just the functions we know about!
These are the “fight or flight” hormones epinephrine (adrenaline) and norepinephrine (noradrenaline). They’re produced in response to hunger, fear and cold as well as excitement.
During labor, maternal CA levels gradually rise, peaking right before transition (the contractions which finish dilating the cervix in the first stage of labor).
This tells us the stress hormones are an important part of a healthy birth. However, if a woman’s epinephrine levels are too high (reflecting activation of her “fight or flight” response) early in labor, uterine contractions will be inhibited and labor will be slowed or even stopped completely.
High levels of CA can stimulate uterine contractions, which contribute to what Michel Odent calls the “Fetus Ejection Reflex“. According to Odent this reflex occurs at transition and almost always follows an undisturbed birth, probably because CA levels must be low early in labor for it to happen optimally.
On the other hand, high levels of CA too early in labor (which would be triggered by activation of the woman’s “fight or flight” system in response to fear or perceived danger) have been shown to inhibit uterine contractions.
This is yet another example of the exquisite regulation of hormones by the body and the danger of interfering with this natural process. CA levels must be just right at all stages for an undisturbed birth. If the mother is afraid or feels she is threatened or in danger early on, labor will be inhibited. I suspect this happens fairly often in the hospital setting. On the other hand, if the natural increase of CA levels that should occur later in labor is blocked (by painkillers or other drugs), then the fetal ejection reflex will not be stimulated and delivery may be more difficult.
Now that we have a better understanding of the hormones involved in birth, we can move on to exploring how modern medical interventions disrupt the natural regulation of these hormones and interfere with “undisturbed birth”.
Articles in this series:
- Natural childbirth I: is homebirth more dangerous than hospital birth?
- Natural childbirth IIa: is ultrasound necessary and effective during pregnancy?
- Natural childbirth IIb: ultrasound not as safe as commonly thought
- Natural childbirth III: why undisturbed birth?
- Natural childbirth IV: the hormones of birth
- Natural childbirth V: epidural side effects and risks
- Natural childbirth VI: Pitocin side effects and risks
- Natural childbirth VII: Cesarean risks and complications