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Differences in risk factors for incident and recurrent small‐for‐gestational‐age birthweight: a hospital‐based cohort study
Author(s) -
Hinkle SN,
Albert PS,
Mendola P,
Sjaarda LA,
Boghossian NS,
Yeung E,
Laughon SK
Publication year - 2014
Publication title -
bjog: an international journal of obstetrics and gynaecology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.157
H-Index - 164
eISSN - 1471-0528
pISSN - 1470-0328
DOI - 10.1111/1471-0528.12628
Subject(s) - medicine , small for gestational age , relative risk , population , obstetrics , underweight , pregnancy , risk factor , incidence (geometry) , pediatrics , cohort , confidence interval , birth weight , body mass index , overweight , genetics , physics , environmental health , optics , biology
Objective Examine whether small‐for‐gestational‐age ( SGA ) risk factors differed by prior SGA birth. Design Hospital‐based cohort study. Setting Utah, USA . Population Electronic medical record data from 25 241 women who were nulliparous at study entry with ≥2 subsequent consecutive singleton deliveries (2002–2010). Methods Estimated adjusted relative risks ( RR ) and 95% confidence intervals (95% CI ) for the association between second pregnancy characteristics and SGA risk. Tested for risk factor differences between recurrence and incidence ( P difference ). Main outcome measures Second pregnancy incident ( n = 1067) and recurrent SGA ( n = 484) determined using a population‐based reference. Results SGA complicated 20.3 and 4.5% of deliveries to women with and without a prior SGA birth, respectively. Young maternal age ( P difference = 0.01) and pregnancy hypertensive diseases ( P difference = 0.03) were associated with incident but not recurrent SGA . Significant risk factors for incidence and recurrence were smoking (incident RR = 1.64 [95% CI 1.22–2.19]; recurrent RR = 1.59 [95% CI 1.17–2.17]), short stature (incident RR = 1.34 [95% CI 1.16–1.54]; recurrent RR = 1.54 [95% CI 1.31–1.82]), prepregnancy underweight (incident RR = 1.32 [95% CI 1.07–1.64]; recurrent RR = 1.30 [95% CI 1.03–1.64]), and inadequate weight gain (incident RR = 1.41 [95% CI 1.22–1.64]; recurrent RR = 1.33 [95% CI 1.10–1.60]). Race‐ethnicity, marital or insurance status, alcohol, diabetes, asthma, thyroid disease, depression, or interpregnancy interval were not associated with incidence or recurrence. Conclusion There was considerable overlap in the risk factors for SGA recurrence and incidence. Recurrence and incidence risk factors included smoking, short stature, underweight, and inadequate weight gain. Maternal age and hypertensive diseases increased the risk for incidence only. Regardless of the SGA definition, some potentially modifiable risk factors for recurrence were identified.