In the study period, from 2006 to 2010, 13 of the 57 maternal deaths were from suicide.
Ms Farquhar said as well as implementing tighter policies for treating pregnant women with a history of mental illness, a specialist mother and baby unit was needed in the North Island to supplement New Zealand's sole unit, in Christchurch.
"There also needs to be better coordination between existing services in the primary and specialist sectors and processes for sharing information between providers,'' she said.
Other most frequent causes of maternal death in the study period were pre-existing medical conditions (11 cases) and amniotic fluid embolism (nine cases).
The leading cause of perinatal deaths in 2010 were congenital abnormality (211 cases), pre-term birth (111 cases) and haemorrhage during pregnancy (78 cases).
"Every one of these deaths is a tragedy. While some were not preventable, we can learn from others to help reduce deaths in the future,'' Ms Farquhar said.
"The report aims to identify where maternity and neonatal services should focus to make the greatest difference.
"New Zealand has very good maternity services but there is always scope to learn and improve.''
She said the most common factors contributing to the avoidable deaths of babies and mothers were not being able to access the necessary health services, such as not booking for pregnancy care, issues with the skills of healthcare professionals and organisational factors like a lack of protocols or delays in procedure.
"Maternity providers need to consider the recommendations from this report and seek to implement them,'' Ms Farquhar said.
Maori and Pacific mothers are more likely to have stillbirths and neonatal deaths compared to New Zealand European and non-Indian Asian mothers.
Teenage mothers are at a higher risk of perinatal-related mortality compared to mothers aged between 20 and 39. Mothers of 40 years and older are also at an increased risk.
Nine per cent of mothers reported using alcohol and 3.4 per cent using marijuana during pregnancy.
Support services
* Mental Health Services: 0508 625 662
* Lifeline: 0800 543 354
* Youthline: 0800 376 633, text 234, email talk@youthline.org.nz
* The Lowdown: text 5626, email team@thelowdown.co.nz
* Depression helpline: 0800 111 757