Experts on preliminary results from new longitudinal study
The first results from the new Auckland-based longitudinal study "Growing Up in New Zealand" were released today at Parliament.
The study will follow more than 7000 Kiwi families over two decades, through pregnancy, birth, childhood and
adolescence, until participating children reach adulthood. This first report presents data from extensive interviews
with expectant mothers and their partners before the birth of the child.
It addresses a wide range of topics, from plans for immunisation, breastfeeding and parental leave from work, through to
ethnic identity, family relationships, economic status and diet, tobacco and alcohol use during pregnancy.
Gathering data before children are born -- instead of relying on parents to recall their experiences during pregnancy
months or years later -- is a unique aspect of this study's design. Also unique is the involvement of fathers and
partners throughout the study, which has not been typical in previous longitudinal studies.
The SMC approached a number of local scientists to look more closely at the various aspects of the report, which can be
downloaded here.
Dr Nikki Turner, director of the Immunisation Advisory Centre at Auckland University, comments on parents' plans for
immunisation, and their sources of information on the subject:
"The trends are consistent with what we're seeing in our other research, which is that immunisation coverage in New
Zealand is currently improving and continuing to improve.
"There's some really good news: the majority of parents are keen to immunize and are expressing a decision to immunise,
which is very positive.
"There are some concerning aspects of it. I think that the underpinning is that we know that nearly 90% of parents make
their decision in the antenatal period, so the antenatal period is really important and it's crucial to get that right.
Some of the concerns that come out of this, particularly, are that about 12% of mothers are still undecided, and more so
with the partners. Our antenatal services should be able to offer good clear information and decision-making support
tools for parents, and clearly, for a significant minority of parents, it's still not happening.
"I think the other piece of concern is that parents had expressed that they had been given discouraging information,
from various sources, which is no surprise because there's a huge amount of information out there in the world. However,
it's particularly concerning if they're picking up discouraging information from health professionals or from antenatal
classes, considering that immunisation is probably the strongest evidence-base we have in all of child medicine
currently. We have immunization programmes in every country in the world, strongly supported by all international health
authorities.
"Finally, there is a significantly higher percentage of people undecided if it's their first child. It is really
important that parents having their first child are clearly informed of the issues around immunization with good
information and good decision-making tools. We clearly do need to do more in the antenatal arena to support parents in
decision-making."
Dr Murray Skeaff, Professor of Human Nutrition at the University of Otago, comments on the intake by mothers of folic
acid:
"For women to benefit from the protective effect of folate on neural tube defects (eg Spina Bifida), folic acid must be
consumed before and through the first month of pregnancy. Folic acid taken after the first month of pregnancy will not
prevent neural tube defects. Thus, by the time most women know they are pregnant it is too late. The results of the
"Growing Up in New Zealand" study showed that slightly more than half of women (58%) who planned a pregnancy took folate
at the correct time before pregnancy. Thus, even amongst women planning a pregnancy, 40% of them were not getting the
benefit of folic acid. Of greater concern is that amongst women with unplanned pregnancies, which represented 40% of all
pregnancies, only 9% of them took folic acid before pregnancy.
"These results reinforce those from previous smaller surveys of pregnant women, that only about 1/3 of New Zealand women
who become pregnant benefit from the NTD protective effects of folic acid supplements. The advantage with folic acid
supplementation is that women can receive the optimum daily dose, 400 µg; however, the obvious disadvantage, for which
the "Growing Up in New Zealand" study provides convincing evidence, is that the vast majority of women do not use folic
acid supplements at the correct time. A proven alternative exists, mandatory folic acid fortification of bread.
Programmes have been implemented recently in Australia and more than ten years ago in the USA and Canada. Mandatory
fortification of bread in New Zealand will deliver about 140 µg/d of folic acid - the amount in three slices of bread -
to women of childbearing age. This amount has dropped NTD rates by almost 50% in Canada."
Lisa Houghton, of the Department of Human Nutrition at the University of Otago, comments on the use of folic acid
supplements:
"In addition to the presentation of the data in the planned and unplanned sub-categories, it would also be useful to
summarise and/or at least highlight in the text, the total number of women who took a folic acid supplement before
pregnancy ie, overall, only 39% of mothers took a folic acid supplement before pregnancy
"This is really the most important aspect of neural tube defect prevention. With respect to the closure of the neural
tube (complete within 28 days postconception), it would be useful to know how many (total) pregnancies have been exposed
to folic acid supplementation prior to pregnancy since post-conception supplementation likely has little preventative
impact with regard to NTDs.
"This overall exposure statement would be quite meaningful in light of the recent deferral of the mandatory folic acid
bread fortification program, which would serve to increase the exposure of all pregnancies (planned and unplanned) to
folic acid prior to conception."
Dr Marewa Glover, Senior Research Fellow at School of Population Health at The University of Auckland, comments on
aspects relating to maternal smoking:
"The report says about half the women quit smoking by last trimester, except for Maori women. However, it should be
pointed out that the percentage amongst European was only 16%, dropping by 8%. Maori women, while not halving, saw a
higher total drop in smoking (13%) from 47% to 34%.
"As the majority of partners are men, there are 2 key important findings (given that it is very rare that information is
collected on partner smoking):
1. "It appears that smoking among Pacific women in the sample is the same or greater than Pacific male smoking (but
was ethnicity the ethnicity of the partner or mother?) .. this is very concerning. I have been speaking out, trying to
warn people that smoking among Pacific women is on the rise and risks imitating what's happened to Maori women.
2. "It is fantastic that so many partners [changed their smoking habits]! This must be one of the most effective
cessation triggers around. It points to the potential for a lot more to be made of this - by the quit campaigns, health
promotion etc."
Susan Pullon, Senior Lecturer at Primary Care and General Practice at the University of Otago, (Wellington) comments on
the maternal nutrition, proportion of unplanned pregnancies, and maternal care:
"This is a comprehensive and good quality report that will be of great use, and further reports will be welcome.
"Specifically, it highlights the need to get more mothers taking folic acid whenever they are not using a reliabel
method of contraception - as opposed to actively planning a pregnancy.
"40 % unplanned sounds a lot but in practice there is a difference between unintended and unplanned - which could be
made clearer in the report.
"I would have liked to see more data as to the timing of enrolment with an LMC (lead maternity carer): the figures for
enrolment by third trimester only tell part of the story. What care did women receive in first trimester? First
trimester care is best practice, whether by enrolment with LMC or other care, yet this data is not presented in the
report."
ENDS