3- and 9-Month Sleep Regressions Explained: Advice from a Baby Sleep Consultant in Marin County

Just when you think you’ve got the hang of it, your baby’s sleeping more easily, maybe even sleeping longer stretches—something changes. Naps are unpredictable, night wakings return, and everyone’s a little more tired (and confused). If that sounds like you, you might be experiencing one of the most common issues I see in my practice: the 3- or 9-month sleep regression.

These regressions aren’t just random phases—they’re real developmental shifts in your baby’s brain and body. As a baby sleep consultant in Marin County, I help parents understand what’s going on and give them the tools to get through it with more ease and less stress.

What Is a Sleep Regression?

A sleep regression is a period when a baby who had been sleeping relatively well suddenly starts waking more often, resisting naps, or having trouble falling asleep. While the timing can vary, the regressions around 3 months and again around 9 months are some of the most noticeable and disruptive.

They’re also signs of progress. These changes often happen when your baby is going through a growth spurt or learning new skills. So while they might feel like setbacks, they’re connected to healthy brain and body development.

What’s Happening at 3 Months?

The first big sleep shift happens between 8-16 weeks. Around this time, your baby’s sleep cycles mature. Instead of drifting into deep sleep and staying there, babies start having lighter and deeper stages of sleep, like adults do.

That’s good long term, but short term, it means your baby will wake up fully at the end of each sleep cycle (every 45 minutes or so during naps and every couple of hours at night). If they haven’t learned to self-settle yet, they’ll need help getting back to sleep.

You might notice:

• Shorter naps

• Frequent night wakings

• Fussiness or clinginess

• More night feedings, even if they weren’t needed before

As a newborn sleep specialist in Marin County, I guide families through this transition gently. It’s not about strict “sleep training” at this age—it’s about understanding your baby’s cues, creating consistent routines, and building a foundation for better sleep down the road.

What Happens Around 9 Months?

The 9-month regression usually shows up between 8 to 10 months. It’s driven by two big developmental leaps: physical mobility and emotional awareness.

Your baby may be crawling, pulling up, or cruising around furniture. Their brain is also working on things like object permanence—so they now realize when you leave the room… and they don’t always love it.

Signs of this regression often include:

• Nap refusal (especially second naps)

• Wakeups that seem to come out of nowhere

• Practicing new physical skills in the crib

• Separation anxiety at bedtime

At this age, we’re looking more seriously at gentle infant sleep training in Marin County—teaching your baby to link sleep cycles and self-settle without feeling abandoned or anxious. It’s about finding that balance between offering support and building independence.

What Can You Do?

There’s no one-size-fits-all answer, but here are strategies I regularly use with families in Marin County:

• Stick to a consistent bedtime routine. Even if sleep is rocky, the predictability helps your baby feel secure.

• Watch your baby’s wake windows. At 3 months, babies often need to rest every 90 minutes; by 9 months, wake windows stretch to 2.5–3 hours.

• Create a calm sleep environment. Think dim lights, white noise, and minimal distractions.

• Respond to your baby, but don’t rush in. Sometimes they just need a minute or two to find their way back to sleep.

• Avoid creating new habits you’ll need to undo. (Like rocking or feeding back to sleep every time.)

• If you’re breastfeeding, know that sleep and feeding are closely linked. As a lactation specialist in Marin County, I often support parents in adjusting feeding schedules alongside sleep needs.

Most importantly, give yourself grace. These phases are challenging but temporary. Your baby isn’t broken—and neither are you.

When to Ask for Help

Sleep regressions are a normal part of development, but can try even the most patient parents. If your baby’s sleep is chaotic for more than a couple of weeks or you’re exhausted and don’t know what else to try, it’s time to reach out.

As a baby sleep consultant in Marin County, I offer personalized sleep plans that take into account your baby’s age, temperament, and feeding needs, along with your family’s unique routine and values. Whether you prefer a home visit, a virtual session or a single call to get pointed in the right direction, we’ll find a solution that fits.

Let’s Create a Plan That Works

If your baby is stuck in the 3- or 9-month sleep regression and you're ready to get things back on track, I’m here to help.

I work one-on-one with families in Marin County to create gentle, practical sleep strategies that support your child’s development and your own peace of mind. There’s no one-size-fits-all method – just real support, rooted in experience.

Let’s get a plan that works for your baby and you. Contact me today to schedule your consultation with a trusted baby sleep consultant in Marin County.