It also highlighted how children in creches are more than twice as likely to suffer poor health compared to those minded by a parent.
The latest Growing Up in Ireland study — which focuses on mothers’ return to work and childcare choices — found only one in five childcare employees had HETAC or third-level qualifications in childcare.
The report which is carried out by the ESRI, said the level of professional qualifications, although highest in childcare centres, was still relatively low by international standards.
It also found more than 50% of child minders and more than 80% of relatives had no childcare-related qualifications.
The study revealed that 39% of infants were in regular non-parental childcare at the age of nine months. Of these 42% were cared by relatives (predominantly grandparents), 31% by non-relatives (mostly childminders) and 27% in centre-based care.
The research, which is part of the first national longitudinal study of Irish children, examined more than 11,000 infants and the patterns of paid employment among mothers following the birth of their baby and the extent and nature of non-parental childcare for infants in their first nine months.
The study found children in centre-based setting for childcare received less one-to-one interaction but had more opportunities for active learning.
They were also at a higher risk of suffering health problems. Infants in a childcare centre were 2.7 times more likely to be rated as “less healthy” than infants in parental care, 2.5 times more likely to have a chest infection, over twice as likely to have an ear infection and twice as likely to have a gastrointestinal infection.
The research found that just 8% of mothers returned to work before their child was six months old — a factor believed to be strongly linked to their entitlement to six months paid maternity leave.
However, a significant proportion of mothers returned to employment over the following months with 30% after seven months and 45% after nine months.
The study found that 85% of mothers who worked prior to birth took their full entitlement to six months paid maternity leave.
“The findings suggest that in Ireland, as in other countries, the duration of paid maternity leave plays a strong role in mothers’ employment patterns after childbirth,” said one of the report’s authors, Frances McGinnity.
The study also found that mothers who returned to work before six months were more likely to be self-employed, young or lone mothers.
The report recommends consideration of introducing regulatory requirements and training supports for childminders as those currently caring for three or fewer pre-school children are exempt from regulation.
Launching the study, Minister for Children Frances Fitzgerald said it provided critical information on the complexity of factors involved in decisions over childcare and when mothers returned to employment.
Ms Fitzgerald acknowledged that although Ireland has the fourth highest rate of child benefit of the 27 EU member states, it did not have the same level of affordable and accessible childcare as other countries.