12-Month Sleep Regression
The short answer
The 12-month sleep regression is driven by major developmental changes - many babies are learning to walk, experiencing separation anxiety, and developing a stronger will. Your baby may start fighting bedtime, waking more at night, refusing naps, or waking earlier than usual. This regression typically lasts 2-6 weeks. The most common mistake is dropping to one nap too early - most 12-month-olds still need two naps. Maintain consistent routines and this phase will pass.
By Age
What to expect by age
The regression often begins around 11-12 months as babies approach their first birthday. They may be pulling up to stand in the crib, cruising, or taking first steps. These exciting motor milestones make it hard to settle down. Your baby might stand in the crib and cry instead of lying down. Separation anxiety also peaks around this time, making it harder for baby to let you leave the room. Practice the new motor skills during the day so they are less compelling at night.
This is the heart of the regression. Common symptoms include: refusing one or both naps, taking much longer to fall asleep at bedtime, waking 1-3 times at night when they previously slept through, and early morning waking. Many parents assume this means it is time to drop to one nap, but this usually makes things worse. Most babies are not ready for one nap until 14-18 months. Keep offering two naps and push through. The regression is temporary.
Most babies come through the regression by 13-14 months and return to their previous sleep patterns if parents maintained consistent routines. If sleep has not improved after 6 weeks, reassess the schedule - ensure wake windows are appropriate (about 3-4 hours between sleeps) and bedtime is not too late. If your baby seems to genuinely not need two naps anymore (consistently taking 30+ minutes to fall asleep for the second nap), it may be time to cautiously trial one nap.
What Should You Do?
When to take action
- Your 12-month-old was sleeping well and suddenly started waking at night or fighting sleep
- The sleep disruption coincides with learning to walk, talk, or other developmental milestones
- Your baby is otherwise healthy, eating well, and developing normally
- Sleep disruption lasts 2-6 weeks and then gradually improves
- Sleep disruption has lasted more than 6 weeks without any improvement
- Your baby seems to be in pain when lying down (pulling at ears, arching back) suggesting possible illness
- Your baby is snoring, mouth breathing, or having pauses in breathing during sleep
- Chronic sleep deprivation is significantly affecting your or your baby's daily functioning
- Your baby has stopped breathing during sleep or has turned blue
- Your baby is extremely lethargic, unable to wake fully, or has a high fever alongside the sleep changes
Sources
Related Resources
Related Sleep Concerns
8-Month Sleep Regression
The 8-month sleep regression is usually driven by major developmental leaps in mobility, cognition, and attachment. Your baby is learning to sit, crawl, pull up, and is developing object permanence and separation anxiety. These exciting milestones can temporarily disrupt sleep, but most babies settle within 2-4 weeks.
18-Month Sleep Regression
The 18-month sleep regression is driven by explosive language development, increasing independence, separation anxiety resurgence, and possibly the transition from two naps to one. Your toddler's vivid imagination may also lead to new nighttime fears. This phase typically lasts 2-6 weeks with consistent routines.
Baby Separation Anxiety
Separation anxiety is a completely healthy sign that your baby has formed a strong attachment to you. It typically begins around 6-8 months, peaks between 10-18 months, and gradually eases by age 2-3. It means your baby's brain has developed enough to understand that you exist even when they cannot see you, but not yet enough to understand that you will always come back.
Dropping from Two Naps to One
Most babies transition from two naps to one between 12-18 months. Signs include consistently fighting or skipping the second nap, taking very long to fall asleep for naps, or bedtime becoming a battle. The transition usually takes 2-4 weeks and some crankiness is normal during the adjustment.
Baby Only Napping 30 Minutes
Short naps of 30-45 minutes are extremely common in babies under 6 months. Your baby is waking at the end of a single sleep cycle and has not yet learned to link cycles together during the day. This is developmentally normal and typically improves on its own between 5-7 months as the brain matures.
Baby Cries Every Time You Put Them Down to Sleep
Many babies cry when placed in the crib because they have learned to associate falling asleep with being held, rocked, nursed, or bounced. This is called a sleep association, and while it is not harmful, it means your baby needs that same condition to fall back asleep each time they wake during the night. Gradually teaching your baby to fall asleep in their sleep space - at whatever pace works for your family - is the foundation of independent sleep. This does not mean you are doing anything wrong; you are meeting a developmental need while gently building a new skill.