ifstudies.org/blog/measuring-the-long-term-effects-of-early-extensive-day-care
Canadian study - Quebec offered free full-working-day child care for ALL under 5s back in 1997 - 2 decades on the results are quite clear - those children that were put into long-hours care from their early months for most of the week “revealed significant increases in anxiety, hyperactivity and aggression” compared to those that weren’t. Crucially - this long term study shows that these adverse effects persist into adolescence and beyond.
Basically - IF, as a parent(s)/prospective parent(s) you have a choice - cut down work- do a day each separately at home, get relatives in to help if you can and minimise the time your 0-3 yr old spends in ALL DAY 9-5+ childcare.
I know there will be a flurry of “my child is fine...” responses but the point of this study is that they have a large sample size. Much more objective than one parent’s view. This is an overall trend when looking at thousands of children over many years.
I understand many truly don’t have a choice (single parents might well often fall into this category) and must use this kind of extensive child care but if you do have a choice - this makes for sobering reading.