One in five mothers experience mental health problems during pregnancy and within the first two years after childbirth.
University of Wollongong researchers however found that only a small percentage of women struggling with mental health difficulties receive treatment, and this can have long-term negative effects for both mother and baby.
Their study highlights the need for further research to enable at-risk mothers and babies to be identified early and accurately.
Lead researcher and PhD candidate Josie McNamara examined 25 studies involving almost 6000 women aged 16-45 years across Australia, Asia, Europe and North America.
"We wanted to determine whether a relationship exists between pregnant women's mental health and maternal fetal attachment - essentially, the emotional bond between mum and baby," Ms McNamara said.
"It was a shock to realise how much researchers still don't know about pregnancy and mother-to-baby bonding."
One of the problems Ms McNamara identified was that researchers can't agree on how to define MFA, or how it should be measured.
"We found seven different names being used to describe the concept of MFA, and 12 different screening tools for assessing it within our review," she said.
"More studies are also needed that span pregnancy and postpartum so that we can better understand the role maternal mental health plays in the developing relationship between mother and baby."
The findings were published in the prestigious open-access journal PLOS ONE, on July 26.
Her paper was co-authored by Associate Professor Jane Herbert from UOW's School of Psychology and Early Start Research, and Dr Michelle Townsend from the School of Psychology and the Illawarra Health and Medical Research Institute.
Ms McNamara is determined to help fill the knowledge gaps revealed by her systematic review.
She is conducting her PhD research at the Wollongong Infant Learning Lab (WILL), under the supervision of Prof Herbert and Dr Townsend.
For the past year, Ms McNamara has been working to better understand the pregnancy and early parenting journey of a diverse group of 122 local women recruited from the Wollongong Hospital Antenatal Clinic.
"When it comes to pregnancy, pregnant women are the real experts. So we've been taking time to ask women about their experiences of pregnancy - the rewarding parts, the difficult parts, and everything in between," Ms McNamara said.