What is the fourth trimester?

Last reviewed June 19, 2026 by Dr. Sapna Jadhav, General Physician. Sources from ACOG, NHS, Mayo Clinic, CDC, NICE, NIH, Cochrane, and peer-reviewed journals.

Bottom lineThe fourth trimester is the first 12 weeks after birth - a recognized transition period when your baby adjusts to life outside the womb and you recover physically and emotionally.

The fourth trimester is the first 12 weeks after your baby is born. It's the name given to this intense period of transition - for the baby, who is adjusting to life outside the womb, and for you, who is recovering physically and emotionally from pregnancy and birth.

Why it matters

For a long time, postpartum care focused on a single check-up at 6 weeks. The idea of a fourth trimester reframes recovery as an ongoing process that deserves attention and support across the whole period, not just one appointment.

What happens for the baby

Newborns sleep, feed, and cry around the clock. They are learning to regulate temperature, digestion, and sleep. Lots of holding, feeding on demand, and skin-to-skin contact help them settle.

What happens for you

• Your body heals and your hormones rebalance.
• You may feel joyful, exhausted, anxious, or all of these.
• Feeding, whether breast or bottle, gets established.
• Your relationships and routines shift.

Getting support

ACOG recommends postpartum care be an ongoing process with contact in the first few weeks, not just a single visit. Reach out to your provider sooner if you have physical or emotional concerns.

Femora supports you through the fourth trimester with cycle, mood, and symptom tracking.