Try not to focus too much on wonder weeks or growth spurts because you might get frustrated when your baby's actions don't line up with what the "experts" say.
Try to go into each day knowing that your baby is going to be different. Feeding, sleeping, temperament, everything. It changes constantly. Unless your LO seems to be in pain or uncomfortable, losing weight or your gut tells you something is wrong, then most likely all is well and your baby is just growing and changing.
Re: Growth spurts?
5 weeks
8-9 weeks
12 weeks
15-19 weeks
23-26 weeks
29-30 may be fussy but not a leap.
Theres more...
But as for your question my book says 3-4 weeks dramatic increase in head circumference. Glucose metabolism also changes in brain.
Try not to focus too much on wonder weeks or growth spurts because you might get frustrated when your baby's actions don't line up with what the "experts" say.
Try to go into each day knowing that your baby is going to be different. Feeding, sleeping, temperament, everything. It changes constantly. Unless your LO seems to be in pain or uncomfortable, losing weight or your gut tells you something is wrong, then most likely all is well and your baby is just growing and changing.