When does colic start in babies? Usually around 2 to 3 weeks of age, with crying that peaks near 6 weeks and eases for most babies by 3 to 4 months. If your baby screams inconsolably every evening and nothing you try seems to reach her, you are not failing as a parent. What you are describing has a name, a predictable arc, and next steps for colic you can take.
When Does Colic Start in Babies? How Long Does it Last?
Most parents notice it arrive almost overnight in the second or third week. The long-standing definition is the 3-3-3 rule, first described by pediatrician Morris Wessel: crying for 3 or more hours a day, 3 or more days a week, for 3 or more weeks, in an otherwise healthy, well-fed baby.
Crying typically peaks around 6 weeks and settles for most babies by 3 to 4 months. You are also in very common company. According to StatPearls via the NCBI Bookshelf, one study found colic in 17% to 25% of newborns and infants under 6 weeks old, dropping to 11% by 8 to 9 weeks and under 1% by 10 to 12 weeks. That last number matters: the crying does end.
The National Center on Shaken Baby Syndrome describes this stretch as the Period of PURPLE Crying, a normal developmental phase that begins around 2 weeks and fades by about 5 months, with crying at its heaviest near the two-month mark. It is a phase, not a verdict on your baby or on your parenting.
Signs of Colic in Newborns and What it Actually Looks Like
The signs of colic go well beyond ordinary fussiness. Parents describe inconsolable crying that builds through the afternoon, a flushed face, clenched fists, an arched back, legs drawn up toward the belly, and a tense abdomen.
The crying also clusters. It tends to land in the late afternoon and evening, which is the window many parents call the witching hour, when nothing in your usual toolkit seems to work. As Tu Mai, MD, and colleagues put it in the journal Gastroenterology Clinics of North America, colic is a characteristic group of behaviors seen in young infants, with prolonged crying as its most prominent feature.
Colic vs. Reflux in Babies: How to Tell the Difference
Colic vs. reflux in babies is one of the most common points of confusion for new parents, and understandably so. Both involve persistent, distressing crying.
Here is a simple way to sort it out. Does the crying happen at roughly the same time each day, whether or not your baby just ate? That points toward colic. Does it spike right after feeds, with spitting up or visible discomfort while swallowing? That points more toward reflux.
Colic follows a time-of-day pattern with no clear trigger. Reflux follows a feeding pattern tied to swallowing and digestion. Plenty of babies show signs of both. It is also worth knowing that tension in the mouth and jaw, including oral ties, can change how a baby latches and swallows, which can look like either one. Start with your pediatrician. Colic is a diagnosis of exclusion, which means other causes should be ruled out first.
Why Colic Happens: The Nervous System Angle
Research still describes the cause of colic as multifactorial and not fully understood. Gut microbiome differences, feeding difficulties, immature digestion, and normal variation in infant crying are all part of the current picture. There is one more layer worth understanding, and it is the one we spend the most time on in our office.
Birth places real physical demands on a newborn’s neck and upper spine, even when everything goes smoothly. For some babies, tension in that area may contribute to a nervous system that stays on high alert instead of settling. When a baby is stuck in that state, especially after experiencing birth trauma, self-soothing is genuinely harder, and the signs of nervous system dysregulation can look a lot like colic from the outside.
Think of a smoke alarm that keeps sounding after the smoke has cleared. Colic’s heaviest weeks also fall in the same early window when a baby’s nervous system is least equipped to regulate on its own. That timing is worth paying attention to.
How to Soothe a Colicky Baby, and When to Look Further
Most families start with the same short list: rhythmic motion, white noise, skin-to-skin contact, upright holding after feeds, gentle tummy massage, and feeding adjustments. Our guide to natural approaches for a colicky baby walks through nine of these in the order we suggest trying them.
These are worth a fair, consistent trial. Give them about two weeks. If your baby’s crying is getting worse, weight gain has stalled, or symptoms line up more with reflux or a food sensitivity, that is your cue to loop your pediatrician back in.
If you have worked the list and nothing has held, a look at nervous system function is a reasonable next step. At Adjusted Living Chiropractic in Chesterton, Indiana, we start with INSiGHT scans, which measure heart rate variability, surface EMG, and rolling thermography, so we can see how a baby’s nervous system is actually functioning before anyone touches her. Adjustments use the Torque Release Technique: light, sustained fingertip pressure, nothing like the twisting or popping adults picture.
This works alongside your pediatrician, your lactation consultant, and any therapist your family already sees. It is not a substitute for any of them.
Dr. Ryan Angelo, DC, has more than seven years of experience in pediatric chiropractic care and practices at the only PX Docs-certified pediatric chiropractic office in Chesterton and Porter County. If your baby’s colic has not responded to the usual approaches, you can read stories from other families in Chesterton or request an appointment to talk it through with Dr. Ryan.
Key Takeaways
- Colic usually starts at 2 to 3 weeks old, peaks around 6 weeks, and eases for most babies by 3 to 4 months.
- One study cited by StatPearls found colic in 17% to 25% of infants under 6 weeks, falling to under 1% by 10 to 12 weeks.
- Signs include inconsolable evening crying, a tense belly, an arched back, and clenched fists, which is different from routine gas or fussiness.
- Colic follows a time-of-day pattern; reflux follows a feeding pattern. Knowing which you are seeing helps you describe it clearly to your provider.
- Nervous system tension after birth may be one overlooked reason a colicky baby struggles to settle, and it is worth assessing with a pediatric chiropractor in Chesterton when home strategies have not helped after about two weeks.
