More than a third of mums feel they have lost their identity since becoming a mother and one in six have wanted to "disappear" at some point since giving birth.
While the vast majority of women say motherhood has made them happier, most also say that they feel overwhelmed, lonely and/or anxious.
The findings are from a survey of 3,708 mothers carried out by online parenting website www.everymum.ie which reveals women go through a rollercoaster of emotions and adaptations while parenting.
An overwhelming 86% of women said they were happier since becoming a mother, yet 73% said they were overwhelmed by the role. While 83% said they liked who they had become as a mum, 62% felt lonely and 60% suffered anxiety.
Of the women who had become mothers in the past year, 62% said they felt overjoyed but 63% said they doubted themselves. While 31% said they felt like Superwoman, 84% were chronically fatigued.
Just over half of all mums (52%) said motherhood was what they expected but the responses from the other 48% made interesting reading. A fifth of them (or roughly one in ten of all the mums surveyed) were less happy than before they became a mum, more than four-fifths (more than a third of the total) felt they had lost their identity and a third (one in six of all) felt like disappearing at some point.
Sinead O'Moore of everymum.ie said the evidence from the study was that many women "kept mum" about their struggles.
The irony is that it is the majority of mums who at times find it challenging and who feel emotions like self-doubt and anxiety. By not sharing these challenges with each other we can isolate ourselves, compare ourselves negatively to others and lose our confidence.