Dad's hormones mirror their partner’s during pregnancy

Ever heard the myth that women’s periods sync up? Well, it's bollocks. Sorry to burst that bubble.

But there is something else involving hormonal synchrony that might surprise you.

^{(never thought I’d say that line in a million years).}

It's called ‘Prenatal Hormonal Synchrony’, and it happens between couples expecting a baby.

What does the science say?

A recent study explored this “physiological synchrony,” where hormones like cortisol (the stress hormone) and testosterone in both men and women tend to align as they prepare for parenthood.

The study reviewed 13 cases and found that expectant parents often experience synchronized hormonal shifts. Cortisol, testosterone, prolactin, and oxytocin showed linkages, particularly around childbirth, influencing behaviours that can strengthen parenting instincts and deepen partner bonds.

Is parental hormonal synchrony good or bad?

So, is prenatal hormonal synchrony all positive? It’s a bit of both. On the plus side, aligned hormones can create a supportive dynamic—more connection, empathy, and shared excitement as both partners transition into new roles.

However, when stress levels (cortisol) rise, this shared intensity can also amplify, meaning one partner’s stress may elevate the other’s, adding tension during challenging moments. It doesn’t really matter if you were the chill one in the relationship and she was the fiery one (or vice versa), that all goes out the window when you’re expecting.

It might even explain why you’ve been getting a bit teary-eyed over rom-coms lately. Don’t deny it.

Signs of Prenatal Hormone Synchrony

Wondering if you’re riding the hormonal wave alongside your partner? Here are some signs that you might be experiencing prenatal hormonal synchrony:

1. Mood swings that feel out of character
   Suddenly snapping at the TV or tearing up at commercials? Emotional highs and lows might be your hormones echoing hers.

2. Heightened sensitivity to stress
   That work email feels heavier than usual, or the thought of assembling the nursery gives you a knot in your stomach? Your cortisol levels could be mirroring the stress your partner feels.

3. A surge of protectiveness
   Feeling extra watchful about your partner’s comfort or wellbeing? Testosterone shifts might be nudging you to step into protector mode.

4. Cravings and appetite changes
   She’s craving pickles and ice cream, and suddenly you can’t stop thinking about doughnuts? Synchrony doesn’t just stop at emotions—your body might join the cravings club.

5. Increased affection or need for closeness
   If you find yourself wanting to hold hands more or just be in the same room as your partner, oxytocin, the bonding hormone, could be at play.

6. Physical symptoms (yes, really!)
   Feeling bloated, queasy, or unusually tired? These sympathy symptoms, sometimes called couvade syndrome, might be more than coincidence.

If these sound familiar, don’t sweat it—these hormonal shifts are just part of your body’s way of preparing for fatherhood. Embrace the ride, even if it means keeping tissues handy for those unexpected teary moments.