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Fourth Trimester: Navigating The Post-Partum Period

10/09/2025

Key summary

  • The fourth trimester, the first 12 weeks post-birth, is crucial for both your recovery and for your baby's transition to the world outside. 
  • Newborns in the fourth trimester need familiar sensations like rocking, swaddling, and closeness to their caregivers to feel secure. 
  • A mother's body undergoes significant healing in the fourth trimester; full recovery can take 12 weeks or longer. 
  • Rest and self-care are vital for mothers during this period. 

When you’re pregnant, there’s a lot of focus on the first, second and third trimesters. But the fourth trimester – the first 12 weeks after your baby is born – is an equally important transition period, with babies adjusting to life on the ‘outside’ and mum is recovering after birth.

“During the fourth trimester, your baby is transitioning from the womb into the world. Parents are adapting to new routines, as well as physical changes and the emotional shift that comes with parenthood,” explains clinical midwife specialist Monique Maitland.

What is the fourth trimester?

The term ‘fourth trimester’ was coined by US paediatrician Harvey Karp in 2002. “It stems from the fact that humans birth very immature infants,” explains sleep coach Claire Fair.

“While some mammals have babies that can walk and feed themselves, human babies are unable to survive on their own [after birth]. They have no way to meet their own needs, so they are biologically wired to want to be in close proximity to their mum during the first 12 weeks of their life.”

What’s happening with my baby in the fourth trimester?

After nine months in the womb, everything is different for your baby. "In the uterus, they're used to a warm, dark, undisturbed environment with constant nutrition and familiar sounds like your heartbeat," says Monique. "When they're born, they have to adjust to light, different sounds, and new sensations."

Because of this, "one of their main priorities is creating attachment to their caregiver through the senses," says Claire. "They want to see, hear, smell and touch you to feel safe and secure."

Ways to help them adjust:

  • Swaying or rocking - helps settle fussy babies
  • Swaddling - mimics the secure feeling of the womb
  • Baby wearing - lets them smell you, hear your heartbeat, and feel your warmth

What's happening with my body in the fourth trimester?

Growing a baby and giving birth put significant stress on your body. "Most women have to heal from birth in some way," says Monique. Whether from vaginal birth tears, episiotomy, C-section, or internal uterine healing, recovery takes time.

"Many people think they'll feel 'normal' after six weeks, but this is rarely the case," says Monique. "Most women take at least 12 weeks to recover physically." Many take longer.

Common symptoms include:

  • Low energy from blood loss
  • Sensitive breasts and nipples from breastfeeding
  • Fatigue from broken sleep


"Rest as much as you can," advises Monique. "Don't pressure yourself to exercise or socialize. Give your body time to heal. If you're worried about symptoms, talk to your midwife or GP."

What's happening with my emotions in the fourth trimester?

Your hormones are in for a wild ride. "Immediately after birth, oestrogen and progesterone levels drop," explains Monique. "This can result in fatigue, mood swings and feelings of sadness - often called the 'baby blues’." Feeling tearful is normal and should level out.

You also release oxytocin, the 'love hormone,' which helps counter fluctuating hormones and supports bonding with your baby.

There's also the emotional adjustment of having your life completely changed. "Dealing with this identity shift can be very challenging," says Monique.

When to seek help:
"These feelings might be particularly strong during the first three to five days after birth, but nobody should go through this alone," says Monique. If you're worried about postnatal depression or anxiety, contact your midwife, GP, or call the PANDA national helpline on 1300 726 306.

The Final Word

The fourth trimester is a profound period of adjustment that deserves attention and care. Be patient with yourself as you navigate this transition – there's no "right" way to experience it. Trust the process, accept help when offered, and remember that this challenging but precious time will pass.

Frequently Asked Questions

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