Week 4: 6 — The First Real Smile

The Quick Brief

Somewhere between week 4 and 6, your baby will look at your face and smile on purpose. Not gas. Not a reflex. An actual social response to you. This moment is evolution's reward for the brutal weeks behind you. Also arriving: the peak of the "purple crying" period, which tests everything you thought you knew about patience.

What's Happening with Baby

The social smile is a genuine developmental milestone. Baby's brain has developed enough to recognize faces, process that recognition, and respond with intentional facial movement. This is the first real evidence that your baby sees you as a person, not just a feeding/comfort source. When it happens—and it will—you'll feel something shift.

Baby is also more alert during wake windows, tracking objects with their eyes, and starting to show preferences for high-contrast patterns and faces. They're developing head control, though it's still wobbly. Tummy time becomes more important now for building neck and shoulder strength.

Here's the hard part: this is also when crying typically peaks. The "Period of PURPLE Crying" is a research-based term describing normal infant crying that peaks around 2 months. PURPLE stands for: Peak of crying, Unexpected, Resists soothing, Pain-like face, Long-lasting, and Evening clustering. This is not colic as a diagnosis—it's normal development. Crying can last hours. It can feel like something is wrong. Usually, nothing is wrong except that babies cry, a lot, at this age.

What's Happening with Mom

By week 4-6, some physical healing has occurred, but exhaustion is often at its worst. The initial adrenaline and visitor support have faded. The accumulated sleep debt is profound. If she's breastfeeding, she's still the primary food source, which means she's never truly "off duty."

The risk for postpartum depression and anxiety increases during this period. Beyond the baby blues, about 1 in 8 women experience postpartum depression. Signs include: persistent sadness lasting more than two weeks, loss of interest in the baby, severe anxiety or panic attacks, difficulty bonding, and intrusive thoughts. If you're seeing these signs, encourage her to talk to her OB or a mental health provider—this is treatable.

If breastfeeding is established, she may be starting to build a pumping routine or freezer stash, especially if return-to-work is on the horizon. This adds another logistical layer to already stretched days.

What Dad Should Do Now

1. Master one soothing technique completely. The 5 S's (swaddle, side-lying, shush, swing, suck) work because they simulate the womb. Pick one and own it. Harvey Karp's approach suggests layering them. Maybe you become the swaddle expert, or you figure out the exact swing rhythm that works. When she's at her limit, having your one reliable technique ready is invaluable.

2. Take the crying shifts intentionally. Don't just help when asked—schedule it. "I've got 7-10 PM, go to another room with headphones." Crying triggers stress responses in both parents, but if she's been with baby all day, her nervous system is fried. Fresh ears help.

3. Protect her sleep aggressively. This is not just "let her sleep in." This is actively creating the conditions for sleep: darkened room, baby handled, no interruptions. One 4-5 hour uninterrupted stretch does more than eight fragmented hours.

4. Watch your own mental health. Paternal postpartum depression is real and affects about 10% of new dads, often peaking 3-6 months after birth. Irritability, withdrawal, anger, and feeling disconnected are warning signs. You can't support her if you're drowning too.

5. Document the first smile. When it happens, try to capture it—you'll want that later. But also, put the phone down and be present for some of them. Those first smiles are specifically for familiar faces and voices. Yours.

The Relationship Check-In

This is often the hardest point in a new relationship with a baby. You're both running on empty. Resentment can build silently—she may feel unsupported even when you're trying; you may feel unappreciated for efforts that go unnoticed.

Try this: once per day, before sleep, each person says one thing the other did that helped. Not a big production, just acknowledgment. "Thanks for handling the 4 AM change." "Thanks for getting groceries." This tiny ritual can prevent the resentment loop from taking hold.

Don't try to solve relationship issues during the crying peak. Just survive together.

What's Coming Up

The 2-month pediatrician visit brings first vaccines—a big milestone. You'll want to attend. Crying typically starts decreasing after the 8-week peak. You're approaching the light at the end of the fourth trimester tunnel. By week 8-10, baby will start cooing and making vowel sounds—your first "conversations."

Quick Reference Box

Sources:

• CDC Milestones: https://www.cdc.gov/act-early/milestones/index.html
• NIH Postpartum: https://www.ncbi.nlm.nih.gov/books/NBK565875/
• CDC Parent Info (Infants): https://www.cdc.gov/parents/infants/milestones-and-schedules.html

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