Tamati Cameron, 29, father of three and soon four, is a supportive kind of guy.
So when his wife Tessa, 28, is pregnant he does what he can to make things smooth for her.
"I try to give her sleep-ins. Three kids [aged 2 to 5], they get up pretty early. If I can get up and give her a bit more time in bed, more time to re-energise."
This sensitive, supportive practice even extends to eating and drinking.
Mr Cameron, an after-school care manager for the YMCA, says he doesn't drink much alcohol, but cut back for his wife's pregnancy. The baby is due next month.
Mrs Cameron, a former high-school teacher, says she was usually a light drinker, but quit when she found she was pregnant.
From the six-month point she started drinking an occasional half glass of wine.
She also avoided cold meats and other deli foods, especially in the early weeks, to minimise the risk of listeria, a food-poisoning bug that can seriously harm a fetus.
And she took folic acid supplements after finding she was pregnant.
She said her husband's drink abstinence and eating more fruit and vegetables had helped her. "He has been great at making it a team thing."
He is part of a trend. The study found that around 40 per cent of the two-thirds of partners who took part modified their diet.
The study says that while a partner changing his diet is unlikely to affect the child study participant's health and wellbeing, "behaviourally it may be easier for a mother to change her own diet if her partner does likewise."
The Camerons' 2-year-old, Isaac, is one of the "leading lights", early entrants to the study who will be used to test the questionnaires.
The Mt Maunganui family also illustrate other trends, such as young families living in rental accommodation and ethnic diversity.
Mrs Cameron is a New Zealand European and Mr Cameron a Maori, of Te Rarawa.
They would like to own their own home eventually, but have put it off while their children are young.
"The priorities for us are the children and making sure that we don't put too much financial stress on the family," Mr Cameron said.
Their expected fourth child may test this resolution, but Mrs Cameron has an answer.
"I've always liked the idea of a bigger family," she says.
* 60 per cent of pregnancies were planned.
* In planned pregnancies, mothers' average age 32; unplanned, 28.
* Planned-pregnancy mothers were two to three times more likely than those in the unplanned group to have a tertiary degree.
* 11 per cent of mothers smoked during pregnancy. Of these, 2 per cent had tertiary qualifications and 43 per cent left school without formal qualifications.
* 76 per cent of planned-pregnancy mothers did not drink during pregnancy; unplanned, 66 per cent.
* 81 per cent of all mothers intended that their children would be fully immunised.
* 90 per cent of mothers intended to breastfeed.
* 87 per cent of mothers avoided some foods or drinks during pregnancy.
* Nearly 16 per cent of mothers did not take folic acid during or immediately before pregnancy.