What 1,531 parents told us about infant sleep

Summary

Between April and September 2026, 1,531 people used this calculator and chose to share their answers anonymously. Those answers describe the sleep environment of 1,531 infants under a year old. Five things stand out.

1. Most families follow the core guidance. 71.5% reported all four of the central safe sleep practices at once: back sleeping, a firm surface, no soft bedding, and no bed or couch sharing.
2. Almost no one is doing everything wrong. The median household reported a single deviation from guidance, and 23.6% reported none at all.
3. Risk factors travel in packs. Households with one deviation are far more likely to have several. Sleep surface risks in particular move together almost as one behaviour.
4. Adherence falls apart with age. The average number of deviations nearly doubles between two and three months (1.24) and six to twelve months (2.23). Every sleep environment measure got worse with age.
5. The most fragile babies get no extra protection. Infants born preterm, underweight, or as multiples had essentially the same number of deviations as everyone else (1.53 vs 1.49).

What parents are getting right

The most consistent signal in this data is a reassuring one. The messages that public health campaigns have pushed hardest for thirty years are the ones that have landed.

Back sleeping is close to universal. 90.3% reported placing the baby on their back. Firm surfaces are the norm at 86.6%, and bare cribs are the norm at 90.9% with no soft bedding, pillows, bumpers, or head covering reported. Overheating, once a common concern, appeared in only 2.5% of responses.

Taken together, 71.5% of households satisfied all four core sleep environment rules simultaneously, and 54.4% met the stricter definition that also requires room sharing on a separate surface and no overheating.

Where the gaps are

Eleven modifiable factors were measured. They are not equally common, and the ranking is informative: the least followed guidance is not the most famous guidance.

Pacifier use is the single largest gap and it is not close. 45.0% reported no pacifier at sleep. Offering a pacifier at naps and bedtime is a genuine AAP recommendation with a real protective association in the literature, but it has never had a campaign behind it the way back sleeping did, and it shows.

Bed sharing and couch sharing at 20.8% is the most consequential gap, because sharing a sleep surface carries one of the strongest associations with sleep related infant death in the published research, and because a couch is the most dangerous surface of all. Seven responses reported couch or armchair sharing specifically.

The smoking and substance use numbers, at 3.7% and 1.2%, are almost certainly understated. These are the questions people are least willing to answer honestly, even anonymously. Treat them as a floor.

Risk factors arrive together, not alone

If these eleven factors occurred independently, the number per household would follow a predictable bell shape. They do not. Both tails are fatter than chance predicts: more families than expected have a perfectly clean sleep setup, and more families than expected have four or more deviations at once.

The clustering is concentrated in the sleep surface. Non-firm surfaces and bed sharing co-occur with an odds ratio of 33.5, soft bedding and non-firm surfaces at 18.7, and soft bedding and bed sharing at 21.2. These are not three separate lapses. They are one decision, described three ways: the baby is sleeping in the adult bed, which is soft by definition and comes with adult bedding. 21.4% of responses fit this pattern, and 5.2% reported all three at once.

One association runs the other way and is worth naming. Bed sharing families were more likely to breastfeed, not less (odds ratio 0.41 for no breastfeeding). This is well documented elsewhere: breastfeeding and bed sharing reinforce each other, which is exactly why blunt advice to never bed share so often fails to change behaviour.

The six month drift

This is the clearest and most actionable finding in the data. Safe sleep practice does not hold steady through the first year. It erodes, and the erosion is broad.

Practice is stable and good through the first three months, then gives way. Six of the eleven factors worsen significantly with age, and the sleep environment measures worsen most.

The likely explanation is not that parents forget. It is that safe sleep advice is delivered almost entirely at birth, in the hospital and at the earliest pediatric visits, and is rarely repeated afterward. Meanwhile the pressures push the other way: sleep regressions around four months, teething, illness, a bigger and more mobile baby, and parents who are further into cumulative exhaustion. The advice arrives when it is easiest to follow and goes quiet exactly when it gets hard.

The most fragile babies get no extra protection

200 responses, 13.1%, described an infant with at least one non-modifiable vulnerability: born preterm, low birth weight, a twin or higher multiple, or born to a mother under 20. In the published research these infants carry a meaningfully higher baseline risk.

Their sleep environments were no safer. Average deviations were 1.53 against 1.49 for everyone else, a difference indistinguishable from zero (p = 0.88).

The detail is mixed rather than uniformly bad. These families were somewhat more likely to use a pacifier and to room share, both protective. But they reported more than double the rate of smoking in pregnancy (7.5% against 3.2%), which is itself a cause of preterm birth and low birth weight, so the same households carry the exposure twice.

Methods

Where the data came from

Everyone who uses the calculator at sidsrisk.com sees an unchecked box reading "Anonymously share my answers to help improve safe sleep research. No personal information is collected." Only responses where a user actively checked that box are included here. Nothing is collected unless the box is ticked. No name, email, IP address, or any other identifier is stored with a response, and the calculator itself runs in the browser.

Repeat submissions are limited by a timestamp held in the browser's own local storage, which permits one submission per browser per 24 hours. That timestamp never leaves the device. Responses are submitted through Google Forms into a private spreadsheet, with Google acting as data processor. All 1,531 responses between 27 April and 1 September 2026 are included. None were excluded, and there was no missing data: every response had all sixteen fields completed.

What was measured

Sixteen self-reported fields: infant age and sex; sleep position, surface, bedding, and room arrangement; overheating; breastfeeding; pacifier use; preterm birth; low birth weight; smoking in pregnancy; postnatal smoke exposure; caregiver substance use; maternal age; and multiple birth. Eleven were treated as modifiable and four as non-modifiable vulnerabilities.

How it was analysed

• Proportions are reported with 95% Wilson score intervals, which behave properly for the small percentages here where the normal approximation does not [8].
• Co-occurrence used chi-square tests, or Fisher's exact test where any expected cell fell below five. Odds ratios use the Haldane-Anscombe correction for stability.
• Trends across the four ordered age bands used the Cochran-Armitage test.
• All families of tests were corrected for multiple comparisons using Benjamini-Hochberg false discovery rate at q < 0.05 [9]. Fifty-four co-occurrence tests were run and 15 survived correction.
• Bed sharing and separate room are derived from the same question and are mutually exclusive by construction, so that pair was excluded rather than reported as a finding.
• The expected distribution in figure 2 is a Monte Carlo simulation of 200,000 households drawing each factor independently at its observed rate.

Checks we ran against ourselves

Infant sex was used as a negative control. There is no reason sleep practice should differ by whether the baby is a boy or a girl, so a difference would suggest something wrong with the data or the analysis. Across all eleven factors, nothing approached significance (smallest q = 0.21), which is the expected result.

Reported practice was also stable month to month across the collection window, with only a slight decline in average deviations over time (rho = −0.08). We do not read anything into a trend that small.

Limitations

These constraints are real and they bound every number above. They are listed in roughly descending order of how much they should change your reading.

• No outcomes, so no risk measurementNot a single SIDS case was observed or recorded, because the people answering are parents of living infants using a planning tool. Nothing here measures risk. Every causal claim about these factors comes from the external research cited below, not from this data.
• A self-selected group, twice overThese are people who sought out a SIDS risk calculator, and then chose to share their answers. Both filters likely select for above-average safety awareness. Real world adherence is probably worse than the 71.5% here, and these figures should not be read as national rates.
• Self-reported and unverifiedNothing was observed or confirmed. The sensitive items (smoking, substance use, bed sharing) face the strongest pressure to under-report, even anonymously, so those prevalences are best treated as floors rather than estimates.
• 1,531 submissions, not 1,531 confirmed infantsThe 24 hour limit is a timestamp in the browser's own storage, so it stops casual repeat entries from the same browser and nothing more. It does not deduplicate across devices or browsers, it resets if someone clears their site data, and it cannot tell two caregivers in one household apart. The true number of distinct infants is unknown and is lower than 1,531.
• Cross-sectional, not longitudinalThe age pattern compares different families at different ages at one moment. It does not follow the same family over time. A cohort effect cannot be ruled out, though the size and consistency of the gradient across six independent measures makes drift within families the more plausible reading.
• Association only, and inside a narrow sliceCo-occurrence is not causation. No socioeconomic, geographic, ethnicity, or household composition data was collected, so none of it could be adjusted for.
• Not independently reviewedThis analysis was run and published by the operator of the calculator. It has not been peer reviewed or reviewed by an ethics board. The underlying counts are available on request so anyone can check the arithmetic.

What we would do with this

Three things follow from the data, stated as what it suggests rather than what it proves.

1. Repeat the advice at four months, not just at birth. The drift begins precisely where the standard delivery of safe sleep guidance has already stopped. A single reminder at the four month visit would land where the gap opens.
2. Talk about the adult bed as one decision. Surface, bedding, and bed sharing move together so tightly they are effectively one behaviour. Advice that treats them as three separate rules is arguing with a decision that has already been made. Families who will bed share regardless are better served by the harm reduction conversation than by a rule they have already declined.
3. Say the pacifier part out loud. It is the largest single gap here at 45%, and the likeliest reason is simply that nobody has run a campaign on it.

Sources

Every causal statement about risk on this page rests on the sources below, not on our data. These are the same references behind the calculator itself.

1. Moon RY, Carlin RF, Hand I; AAP Task Force on SIDS. Sleep-Related Infant Deaths: Updated 2022 Recommendations. Pediatrics. 2022;150(1):e2022057990.
2. Centers for Disease Control and Prevention. Sudden Unexpected Infant Death and SIDS: Data and Statistics.
3. Carpenter R, McGarvey C, Mitchell EA, et al. Bed sharing when parents do not smoke: is there a risk of SIDS? BMJ Open. 2013;3(5):e002299.
4. Hauck FR, Omojokun OO, Siadaty MS. Do pacifiers reduce the risk of sudden infant death syndrome? A meta-analysis. Pediatrics. 2005;116(5):e716-23.
5. Hauck FR, Thompson JM, Tanabe KO, et al. Breastfeeding and reduced risk of sudden infant death syndrome: a meta-analysis. Pediatrics. 2011;128(1):103-10.
6. Anderson TM, Lavista Ferres JM, Ren SY, et al. Maternal smoking before and during pregnancy and the risk of sudden unexpected infant death.
7. Eunice Kennedy Shriver National Institute of Child Health and Human Development. Safe to Sleep: Known Risk Factors, covering prematurity, low birth weight, soft bedding, and head covering.
8. Wilson EB. Probable inference, the law of succession, and statistical inference. Journal of the American Statistical Association. 1927;22(158):209-212. Method used for all confidence intervals here.
9. Benjamini Y, Hochberg Y. Controlling the false discovery rate: a practical and powerful approach to multiple testing. Journal of the Royal Statistical Society Series B. 1995;57(1):289-300. Method used for all multiple-comparison correction here.
10. U.S. Consumer Product Safety Commission. CPSC Cautions Consumers Not to Use Inclined Infant Sleep Products. 2020.