Letting your baby cry briefly, particularly during sleep training, is generally considered safe and does not cause lasting harm. Most major pediatric organizations support structured approaches to sleep training that involve some crying, and the best available evidence shows these methods do not raise stress levels in babies over time. That said, there’s an important distinction between short, purposeful periods of crying during sleep learning and leaving a baby to cry for extended stretches with no response to their needs.
How Much Crying Is Normal
All babies cry. It is their only way to communicate hunger, discomfort, tiredness, or overstimulation. A healthy baby typically has one to two hours of unexplained crying each day, meaning crying that happens even when nothing obvious is wrong. Some babies are harder to comfort and cry more than three hours a day, which is often labeled colic. This kind of crying tends to peak around six to eight weeks of age and usually improves significantly by three to four months.
So if your baby is crying and you’ve checked all the basics (fed, clean diaper, comfortable temperature, not in pain), some crying is simply part of being a baby. It does not mean you’re doing something wrong.
What Sleep Training Research Actually Shows
The most common concern parents have is about “cry it out” methods of sleep training, where you put your baby down awake and allow them to cry for a set period before checking in. A study conducted through the American Academy of Pediatrics divided infants into two groups: one that went through sleep training and one that did not. Researchers measured cortisol, a hormone the body produces under stress. By the end of the training period, babies in the sleep training group actually had decreased cortisol levels compared to before, suggesting their stress was going down, not up.
This finding runs counter to the fear that sleep training floods a baby’s system with stress hormones. Babies who learn to fall asleep independently often settle faster, wake less frequently, and appear less distressed overall within a matter of days or weeks.
The Case Against Extended, Unresponsive Crying
The debate gets more complicated when you look beyond structured sleep training. Some developmental researchers argue that leaving babies to cry without any caregiver response can disrupt how their stress systems develop. The concern is that when an infant repeatedly signals distress and gets no answer, they don’t learn to “self-soothe” so much as they learn to shut down. Over time, the argument goes, this can undermine a child’s sense of trust, affect emotional regulation, and shape how they handle stress into adulthood.
Erik Erikson’s classic framework on child development placed the first year of life as a critical window for building trust. When a baby’s needs are consistently met, they develop confidence that the world is safe and that relationships are reliable. When those needs are repeatedly ignored, the opposite pattern can take hold. Research on caregiver responsiveness broadly supports this: babies whose caregivers respond to their needs tend to show better outcomes across intelligence, empathy, emotional regulation, and social skills.
It’s worth noting that this body of work is largely about chronic, pervasive neglect of an infant’s needs, not about a ten-minute stretch of crying at bedtime while a baby learns to fall asleep. The distinction matters enormously. A parent who uses a graduated sleep training method, checks in at intervals, and is warm and responsive during waking hours is in a completely different category from a caregiver who routinely ignores a distressed baby.
Your Mental Health Is Part of the Equation
One factor that often gets left out of this conversation is what happens to you. Sleep deprivation is one of the strongest predictors of postpartum depression, anxiety, and stress. A study published in BMJ Open tracked mothers before and after implementing an infant sleep intervention. The results were striking: the proportion of mothers with any degree of depression dropped from 32.5% to just 5%. Anxiety fell from 25% to 15%, and stress from nearly 49% to 20%. Depression scores specifically showed a 66% mean reduction.
These are not small numbers. A parent who is severely sleep-deprived, depressed, or overwhelmed is less able to be the responsive, attuned caregiver their baby needs during the other 23 hours of the day. If allowing some crying at bedtime means you can function, bond, and be present when your baby is awake, that trade-off can be a net positive for the whole family.
How to Tell If Crying Signals a Problem
Normal crying, even loud and persistent crying, looks like a baby who is otherwise healthy between episodes. Their fingers, toes, and lips stay pink and warm. They breathe without difficulty. They feed well and have normal wet and dirty diapers.
Crying that warrants immediate medical attention looks different. Watch for fever, vomiting, diarrhea, rash, or any difficulty breathing. Check for physical causes like swelling, redness, cold extremities, twisted limbs, a folded earlobe, or a hair wrapped around a finger or toe (called a hair tourniquet, and more common than you’d expect). If your baby’s cry suddenly changes in pitch or intensity, sounds unusually high-pitched, or if your baby becomes inconsolable in a way that feels distinctly different from their usual fussiness, that’s worth a call to your pediatrician.
A Practical Way to Think About It
The question isn’t really whether any amount of crying is acceptable. Crying is inevitable. The real question is whether your baby’s needs are being met overall, and whether your approach to crying fits within a broader pattern of warmth and responsiveness.
If you’re using a sleep training method where your baby cries for short, predictable intervals while learning to fall asleep, the evidence suggests this is safe and can benefit both of you. If you’re responding to your baby’s hunger, discomfort, and need for connection throughout the day, brief crying at bedtime is not going to erode their trust or damage their development. Babies are resilient, and secure attachment is built across thousands of interactions, not undone by a few minutes of protest at lights-out.