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.