Have you heard that when mothers return to work within the first year of life, sending their child to daycare, this can result in later attachment issues, disobedience, and aggression? Don’t panic. It is not that straight forward.

I began researching this based on a subscriber email I received:

I just bumped into an article claiming that many hours of nursery in children under the age of two lead to aggression and insecurity later in life. I googled it and all the articles I found suggested the same thing. Is this all based on one study or are the majority of (good quality) studies suggesting it? It got me really worried and wondering whether I should try to reduce my hours drastically until she is at least two years old?” – Kat

Here is my response:Daycare 400

The big scale US National Institute of Child Health and Human Development (NICHD) studies seem most trustworthy because they measure the quality of care. Better quality care was when care givers were more sensitive (even to non-distress), provide cognitive stimulation, positive regard, foster exploration, and show less negative regard, detachment, flatness of affect, and intrusiveness (1, 2, 3).

Better quality care (and especially centre-based care) in the first four years was related to better cognitive outcomes (language, memory and pre academic skills) at 4.5 and early primary school, though effects got smaller with age (2, 3).

More hours of care, controlling for quality, was associated with more behavioural problems at 4.5 and in early primary school as rated by the teachers (the same effect was not found for parent-ratings). Hours of care was measured in hours per week averaged from 6 months to 4.5 years. It is therefore hard to distinguish children who started daycare at 6 months with moderate hours of care, from children who started later with high hours of care. Behavioural Problems included internalising problems such as anxiety and withdrawal, and externalising problems, such as rule-breaking and aggressive behaviour based on the Child Behaviour Checklist.

Other studies raise concerns about children starting daycare early, with recommendations ranging from no earlier than 9 months to no earlier than 18 months. However, most of these don’t measure the quality of childcare or problems are limited to cases where parents return to work early and the quality of childcare is poor.

How and why could daycare cause behavioural problems?

Children form a primary attachment to their mother and secondary attachments to other familiar caregivers. Attachment forms primarily in the first year but the first 3 years is thought to be a sensitive time for attachment. Insecure attachment is a major risk factor for a whole lot of problems throughout life and relationships. Two major concerns, which have not been validated empirically are:

  1. Disrupted Attachment: The attachment to the mother might be compromised because it is not given the necessary time to form, or the child has to endure so many sustained absences, that it is no longer felt to be a secure or safe relationship (insecure attachment).
  2. Stress: When young children don’t have access to an attachment figure, they have an “attachment seeking response”. The theory is that if no attachment figure is available they may disengage from that response and seem outwardly OK, but still be feeling heightened stress due to the unavailability of an attachment figure. Even if childcare staff are extremely sensitive, they are effectively strangers at first, not attachment figures.

What does the evidence say?

Disrupted Attachment

Disrupted Attachment was primarily found when young children spent days and weeks in hospital with limited parental contact. This is quite different from a situation where the mother can be trusted to return every afternoon and be around all night. A 2004 paper found that attachments remained or became secure if mothers spent more days adapting their 11-20 month old to childcare (4). A 1997 NICHD study found mother-child attachment was not affected by the return to work unless mothers were also insensitive to their child and the childcare was poor-quality or unstable or extended hours (1).

Based on the research, daycare itself doesn’t seem to be a risk factor for insecure attachment.


A 2004 study found that children did have increased stress hormone (cortisol) during adaptation and separation phases at preschool (not surprisingly). The level of cortisol had decreased 5 months later, but was still somewhat higher than when they were at home. These were toddlers who started childcare between 11 and 20 months of age. Children who already had a secure attachment with their Mum had lower levels of cortisol during adaptation (mother and child at the childcare centre) and fussed and cried less during the separation than children with an insecure attachment.

Based on this research it seems stress levels are higher at daycare (as you would expect just from the level of activity and excitement). A secure attachment with Mum may act as a protective factor by lessening the stress level somewhat. We know that adults suffer all sorts of mental and physical health problems as a result of chronic stress (stress that persists for a long time). The longer children are at daycare, per week, the longer they experience this heightened stress. We do not know what the short or long term effects are. Studies show the stress level in the morning at daycare is higher than home-life, but is it higher than a playdate in the park? Shopping with the kids? Family meltdowns at home? We do not know.

Based on the research, daycare is more stressful (could also mean exciting/fun/active) than home life. In small doses this is unlikely to be a problem. For long hours, we just don’t know.

Other Factors

So many other factors are likely to come into play here. A big one is how happy Mum and Dad are with the work-life balance. How well they cope with the work demands, keep up with the family demands, manage to schedule in time with their kids, and switch off from work for long enough to make kid-time into quality time. The longer the daycare hours, the harder this is to achieve, but that doesn’t mean it can’t be done.

When to start Daycare: Take home messages

I agree with Belsky’s comments from this Guardian article. The effects are small enough, that it is hard to translate to recommendations for your child. If your child is in high hours of daycare from 6 months of age, there is an increased risk of behavioural issues down the track. There may be major behavioural issues, minor behavioural issues, no behavioural issues. We can’t predict for individual cases and it depends on a whole lot of other family and child factors also. One important factor is how happy the parents are and this is likely to be affected by the experienced work-family balance. It’s the governments, looking at the effects on society as a whole, who need to consider these effects seriously.

How much is too much?

Your best indicator will be your own family functioning. Are you coping with the workload? Are you able to switch off from work when you are with your kids? Are you getting quality time with your kids and your partner? Are interactions more positive than negative (aiming for about a 5:1 ratio)?

I can’t afford to work any less!

Some families cannot afford to work less than they do. Don’t let this be another source of guilt. When you see your kids, be there for them 100%. Increase the quality of time together, and let go of the worry about lack of quantity.