Original Article
Antenatal care, identification of suboptimal fetal growth and risk of late
stillbirth: Findings from the Auckland Stillbirth Study
Tomasina STACEY,
1,2
John M.D. THOMPSON,
3
Edwin A. MITCHELL,
3
Jane M. ZUCCOLLO,
4
Alec J. EKEROMA
1
and Lesley M.E. McCOWAN
1
1
Department of Obstetrics and Gynaecology, University of Auckland, Grafton,
2
Department of Health Sciences, AUT University,
Akoranga,
3
Department of Paediatrics, University of Auckland, Grafton, Auckland, New Zealand and
4
Department of Obstetrics and
Gynaecology, Wellington Medical School, Wellington, New Zealand
Introduction: Stillbirth remains an important public health problem in Australia and New Zealand. The role that
antenatal care plays in the prevention of stillbirth in high-income countries is unclear.
Methods: Cases were women with a singleton, late stillbirth without congenital abnormality, booked to deliver in the
Auckland region and born between July 2006 and June 2009. Two controls with ongoing pregnancies were randomly
selected at the same gestation at which the stillbirth occurred. Data were collected through interview-administered
questionnaires and from antenatal records.
Results: One hundred and fifty five of 215 (72%) cases and 310 of 429 (72%) controls consented to take part in the
study. Accessing <50% of recommended antenatal visits was associated with a more than twofold increase in late stillbirth
(adjusted odds ratio, aOR, 2.68; 95% CI, 1.04–6.90) compared with accessing the recommended number of visits. Small-
for-gestational-age (SGA) babies that had not been identified as SGA prior to birth were significantly more at risk of
being stillborn (aOR, 9.46; 95% CI, 1.98–45.13) compared with SGA babies that were identified as such in the antenatal
period. No relationship was found between type or model of maternity care provider at booking and late stillbirth risk.
Discussion: This study reinforces the importance of regular antenatal care attendance. Identification of SGA may be one
way by which antenatal care reduces stillbirth.
Key words: antenatal care, New Zealand, risk factors, small for gestational age, stillbirth.
Introduction
Stillbirth remains a common and devastating complication
of pregnancy. More than 7 in 1000 births in Australia and
New Zealand result in a stillbirth (fetal death 20 weeks
gestation) with more than 1 in 300 resulting in late stillbirth
(death 28 weeks gestation).
1–3
During the 20th century,
there was a significant reduction in the rate of stillbirths in
high-income countries, in considerable part because of
improvements in antenatal care.
4,5
Unfortunately, the
stillbirth rate has decreased little in the last two decades.
3,6–8
Although antenatal care attendance is associated with
improved perinatal and maternal outcomes, the actual
number of antenatal visits required to make a difference
to perinatal mortality is unclear.
9
No previous studies
have explored the relationship between antenatal care
utilisation and risk of late stillbirth in New Zealand. The
model of maternity care provision in New Zealand altered
significantly in the early 1990s following the Nurses
Amendment Act of 1990, which resulted in a change
from a predominantly doctor-led to a midwifery-led
model of care. However, there have been no studies that
have explored the relationship between type of maternity
care provider or model of care and late stillbirth risk in
New Zealand.
It is unclear what specific aspects of antenatal care
might be associated with reduced risk of stillbirth. A
relationship has long been established between suboptimal
fetal growth and risk of stillbirth.
10,11
A small number of
publications have also reported that the large majority of
stillborn small-for-gestational-age (SGA) infants are not
recognised before birth, but these studies have not had
comparative rates of antenatal SGA recognition in a
control population of live-born infants.
1,12
The primary aim of the Auckland Stillbirth Study was
to identify modifiable risk factors for late stillbirth. The
specific aim of this analysis was to assess the relationship
between antenatal care and late stillbirth risk.
Correspondence: Tomasina Stacey, University of Auckland,
Private Bag 920219, Auckland, New Zealand.
Email: t.stacey@auckland.ac.nz
Received 5 May 2011; accepted 5 December 2011.
242 © 2012 The Authors
Australian and New Zealand Journal of Obstetrics and Gynaecology © 2012 The Royal Australian and New Zealand College of Obstetricians and Gynaecologists
Australian and New Zealand Journal of Obstetrics and Gynaecology 2012; 52: 242–247 DOI: 10.1111/j.1479-828X.2011.01406.x
he Australian and
New Zealand Journal
of Obstetrics and
Gynaecology