There is not enough talk about what happens to your hormone levels after you have given birth. As postnatal women we are often left in the dark not fully understanding the immediate changes that occur after labor and the dramatic affect this has on us.

When you are pregnant we talk a lot about hormones and that for the most part they increase in production for many wonderful reasons:

  • changing and preparing our bodies for the pregnancy ahead
  • efficient development of our growing babies
  • they are particularly important before and during labor

Let’s now examine the relevant postnatal hormones - how the levels changed and what effect this can have.

ESTROGEN

DURING PREGNANCY

  • Estrogen is produced in large amounts by the ovaries
  • It strengthens and prepares the womb for implantation of the fertilized egg
  • It prepares the breasts for breastfeeding by enlarging the nipples and encouraging the development of milk glands
  • It regulates the development of the fetus and maintains the endometrium during pregnancy

WHEN YOU ARE POSTNATAL

  • The high level of estrogen falls immediately after the birth
  • It usually takes around 6 – 8 weeks for these levels to increase enough again to initiate menstruation
  • Breastfeeding mums may not menstruate again until they begin weaning

PROGESTERONE

DURING PREGNANCY

  • Progesterone is produced in large amounts
  • It stimulates the thickening of the uterine lining in anticipation of implantation of a fertilized egg
  • It relaxes the smooth muscle of the uterus to prevent muscle contractions that could otherwise trigger miscarriage
  • Importantly to note - It inhabits the production of monoamine oxidase (MAO) in the brain, which usually produces depressive reactions. This is one of the big reasons you feel almost euphoric during pregnancy, particularly in your 2nd trimester when the exhaustion and sickness of the first trimester has passed. *This massive shift in progesterone can have the opposite effect and pregnancy depression can occur
  • It also increases body temperature, dilates blood vessels and relaxes muscle in the bladder, bowel and veins so that they are more flexible

WHEN YOU ARE POSTNATAL

  • Progesterone levels drop within hours of birth and is most likely the cause of the ‘baby blues.”
  • The large amounts have been suppressing the production of MAO in the brain so when this drops - the MAO will increase. This can be more extreme in some women and can develop, along with other factors, into post-partum depression
  • It also helps in the production of breast milk

RELAXIN

DURING PREGNANCY

  • Relaxin is produced by the placenta
  • The high levels cause joint and ligament laxity - softening not only the cervix and tissue of the birth canal throughout the entire body

WHEN YOU ARE POSTNATAL

  • Relaxin release is stopped immediately after birth but the effects can continue into the postnatal period and stability should remain a focus when working out
  • It also widens blood vessels, lowering blood pressure and so can contribute to a feeling of dizziness

4. OXYTOCIN

DURING PREGNANCY

  • Oxytocin is the pleasure or ‘love’ hormone of the body and is naturally secreted when you have sex
  • It causes contractions of the uterus and stimulates the labor process, continuing to be released throughout delivery

WHEN YOU ARE POSTNATAL

  • Oxytocin is stimulated during breastfeeding and is responsible for the “let-down of milk” reflex
  • It is associated with bonding and attachment of mother and child – which often first occurs when breastfeeding your baby.
  • Oxytocin continues to cause uterine contractions after birth to help the uterus reduce back to its pre-pregnancy size

PROLACTIN

DURING PREGNANCY

  • Prolactin is not produced in large amounts during pregnancy and is more sIgnificant during the postnatal period

WHEN YOU ARE POSTNATAL

  • Prolactin is closely associated with the breastfeeding process.
  • It is produced on a supply and demand basis after estrogen levels fall after birth
  • It is the hormone responsible for milk production
  • It aids in the stabilization the mother’s mood
  • It helps promote the bond between mother and baby