by Rachel Gardner, founder and Chief Executive of Forging Families

Did you know that the Mum isn’t the only one who has hormonal changes during pregnancy and birth?

Dad Hormones

Researchers at the University of Michigan have done a really interesting study into the hormonal changes of men in the later stages of their partner’s pregnancy, birth and the first 12 weeks of their newborns life outside the womb. The study was published in the peer-reviewed American Journal of Human Biology.

“Wynne-Edwards and colleagues propose that paternal behavior involves the activation of the same neuroendo-crine pathways generally associated with maternal care (Wynne-Edwards, 2001; Wynne-Edwards and Reburn,2000).

It is widely known that women go through huge hormonal changes when they are pregnant, during birth and whilst breast feeding but what a great surprise to find out that Dads also experience hormonal changes to help prepare them for birth and Fatherhood.

“As expected, women showed large prenatal increases in all four hormones. Men showed significant prenatal declines in testosterone and estradiol”

For me, this is indeed a wonderful way to show men that yes, of course they should be at the birth of their baby but more than that they should be awesome at the birth of their baby. Some critics would argue that the study was very small and the suggestion that these hormonal changes affect behaviour is, as yet, unproven. We do, however know the effects these same hormones have on Mums and as Wynne-Edwards states “Male and female brains are remarkably similar”

I think it’s an exceptionally exciting avenue of study and one that absolutely makes sense for me, having seen Dads in the later stages of a pregnancy, birth and after.

So what are these hormonal changes and how might they affect Dads?


Testosterone is the hormone that can be linked to heightened aggression and competitiveness; it is thought to be a component of the mating process and testosterone levels rise dramatically during sex, sports or competition. It is not known for promoting caring and nurturing feelings. After birth it has been found that men’s testosterone levels drop dramatically. Psychologist, Ross Parke, from the University of California, states that this drop in testosterone could “let the nurturing side of men come to center stage.”

The study by Wynne-Edwards of Michigan clearly states:

“Cross-sectional research consistently demonstrates that fathers have lower testosterone than non-fathers (Grayet al., 2006; Perini et al., 2012).”

Wynne-Edwards agrees with psychologist Ross Parke when she says:

“Post-birth declines in testosterone are thought to support paternal care by reducing aggression toward infants, focusing attention away from mating effort, and/or facilitating paternal attachment (Wynne-Edwards, 2001).”

So what is known is that testosterone levels do drop after birth for up to seven weeks and it is widely considered that this is to facilitate the bonding and nurturing process of being a Daddy.


Estrogen (in this case estradiol) promotes caring and bonding in humans and mammals. Mums have a significant rise in estrogen throughout pregnancy and the early months after birth. Mileva-Seitz and Fleming said that “Estradiol is associated with caregiving and bonding in humans and other mammals (Mileva-Seitz and Fleming,2011).”

This study has found that Dads too, experience an increase in estrogen/estadiol for approximately 4 weeks before birth and continuing for up to 12 weeks after birth; these higher levels of estrogen induce much more caring and nurturing feelings in new Dads.

“New fathers also had higher estradiol levels than a comparison sample of menwithout children (Berg and Wynne-Edwards, 2001), again suggesting an increase in estradiol as a function of fatherhood.”


“Higher levels of postpartum maternal cortisol have been associated with affectionate … behaviour toward infants (Fleming et al., 1987), suggesting that cortisol may facilitate maternal behaviour by preparing mothers for the challenge of caregiving (Mileva-Seitz and Fleming, 2011).”

In a cross-sectional study of expectant new Fathers it was found that Dads experienced more cortisol as their partner’s pregnancy developed and “there is some evidence that expectant fathers’ cortisol levels may increase close to the delivery, perhaps in preparation for caregiving (Storey and Walsh, 2011)”

These are not the only hormones that a new Dad benefits from. Raised vasopressin levels cause a new Dad and expectant Dad to want to protect his family and increases loyalty. Vasopressin makes Dads more aware and in tune with their partner, and is of great use to Dads during birth.

Oxytocin (the “love hormone”) is released in large quantities during skin to skin and is a must for all new Dads.


The Wynne-Edwards study and cross-sectional studies show that there is a drop in testosterone, a rise in estrogen and a rise in cortisol. It is known that these changes promote bonding and nurturing, and that it can be presumed that the same happens within Dads not just towards their new baby but also towards their partners.

We also know that vasopressin promotes the want to protect and look after and oxytocin again promotes feelings of love and bonding.

All these hormones play their part in preparing Dads for their new journey of Fatherhood and help them be the best birthing companion they can be.