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Independent risk factors for infants who are small for gestational age by customised birthweight centiles in a multi‐ethnic N ew Z ealand population
Author(s) -
Anderson Ngaire H.,
Sadler Lynn C.,
Stewart Alistair W.,
Fyfe Elaine M.,
M Lesley M.E.
Publication year - 2013
Publication title -
australian and new zealand journal of obstetrics and gynaecology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.734
H-Index - 65
eISSN - 1479-828X
pISSN - 0004-8666
DOI - 10.1111/ajo.12016
Subject(s) - medicine , small for gestational age , odds ratio , population , obstetrics , placental abruption , gestational age , body mass index , gestational hypertension , gestational diabetes , birth weight , eclampsia , pregnancy , preeclampsia , gestation , environmental health , genetics , biology
Background Infants born small for gestational age ( SGA ) by customised birthweight centiles are at increased risk of adverse outcomes compared with those SGA by population centiles. Risk factors for customised SGA have not previously been described in a general obstetric population. Aim To determine independent risk factors for customised SGA in a multi‐ethnic N ew Z ealand population. Methods We performed a retrospective cohort analysis of prospectively recorded maternity data from 2006 to 2009 at N ational W omen's H ealth, A uckland, N ew Z ealand. After exclusion of infants with congenital anomalies and missing data, our final study population was 26,254 singleton pregnancies. Multivariable logistic regression analysis adjusted for ethnicity, body mass index, maternal age, parity, smoking status, social deprivation, hypertensive disease, antepartum haemorrhage ( APH ), diabetes and relevant pre‐existing medical conditions. Results Independent risk factors for SGA included obesity (adjusted odds ratio 1.24 [95% CI 1.11–1.39] relative to normal weight), maternal age ≥ 35 years (1.16 [1.05–1.30] relative to 20–29 years), nulliparity (1.13 [1.04–1.24] relative to parity 1), cigarette smoking (2.01 [1.79–2.27]), gestational hypertension (1.46 [1.21–1.75]), pre‐eclampsia (2.94 [2.49–3.48]), chronic hypertension (1.68 [1.34–2.09]), placental abruption (2.57 [1.74–3.78]) and APH of unknown origin (1.71 [1.45–2.00]). Gestational diabetes (0.80 [0.67–0.96]) and type 1 diabetes (0.26 [0.11–0.64]) were associated with reduced risk. Conclusions We report independent pregnancy risk factors for customised SGA in a general obstetric population. In contrast to population SGA , obesity is associated with increased risk. Our findings may help identify pregnancies that require increased fetal growth surveillance.