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Night Waking from 6 to 18 Months: Why Self-Settling Is the Real Variable

By Leon MoriguchiPublished May 15, 2026Updated May 18, 20265 min read日本語版あり
Audience
Parents of infants aged 6 months to 18 months

TL;DR

  • ·All infants wake repeatedly during the night at every age studied; parents who believe their infant "never wakes up" are accurate that their infant never signals them — not that no arousal occurred
  • ·The primary driver of consolidated nighttime sleep is the development of self-regulated sleep (the ability to re-settle without caregiver assistance), which varies considerably across individuals and is most directly influenced by conditions present at sleep onset
  • ·Many infants who are described as "bad night wakers" fall asleep with help at bedtime and cry in the night to recreate those absent conditions — the mismatch between sleep-onset and middle-of-the-night conditions is the lever, not waking frequency itself

Contents

  1. Lead
  2. Night waking is universal — the "sleeping through" baby is a myth
  3. Why 6–18 months: the developmental context
  4. The self-settling reframe
  5. What to do with this
  6. Summary
  7. References

Lead

Two in the morning. The child cries. You pick up, the crying stops. You put them down, they cry again. After the third round, lying awake at 4 a.m. wondering whether something is wrong, you are not alone.

"Night waking" (yonaki in Japanese, used broadly for any nighttime crying) covers at least two distinct phenomena that are worth separating: the waking itself, and what happens afterward — specifically, whether the infant can return to sleep independently or signals for help. That distinction changes how the problem looks and what, if anything, can be done about it.

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In the memori app

The memori app is built so you can check these patterns against your records instead of your memory.

  • Bedtime sessions: time-to-sleep accumulates separately for each method you try — rocking, lying down beside them, white noise.
  • A per-night tally of how many feeds and wakings there were.
  • White noise and ambient sound, with a caution when the volume climbs too high.
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