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Should parity be included in customised fetal weight standards for identifying small‐for‐gestational‐age babies? Results from a French multicentre study
Author(s) -
Ego A,
Subtil D,
Grange G,
Thiebaugeorges O,
Senat MV,
Vayssiere C,
Zeitlin J
Publication year - 2008
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/j.1471-0528.2008.01855.x
Subject(s) - parity (physics) , small for gestational age , medicine , obstetrics , singleton , caesarean section , birth weight , gestational age , pregnancy , pediatrics , physics , particle physics , biology , genetics
Objective Parity is one of several parameters used to customise fetal growth norms. However, it is uncertain whether the lower birthweight of babies born to primiparous women reflects physiological or pathological variation. Our aim was to assess the impact of adjusting for parity in identification of small‐for‐gestational‐age (SGA) births. Design Comparison of two customised definitions of SGA with and without parity. Setting Routinely collected data in five tertiary maternity hospitals in France. Population A total of 51 126 singleton births without malformations from 1997 to 2002. Methods Characteristics of mothers and babies and adverse pregnancy outcomes for SGA and non‐SGA births were compared using customised definitions with and without parity. Main outcome measures Neonatal morbidity and mortality. Results SGA births among primiparas increased from 14.9 to 18.0% when parity was excluded. Overall rates of SGA rose from 14.4 to 15.0%. Newly defined cases of SGA were babies of primiparas. They had higher rates of admission to a neonatal unit and caesarean section than babies reclassified as non‐SGA. Perinatal mortality was 9.1‰ (parity included) and 9.7‰ (parity excluded) and did not differ significantly from babies classified as non‐SGA by both standards (5.4‰). Conclusions Adjustment for parity markedly decreased the proportion of primiparas diagnosed with SGA babies but did not appear to improve the identification of high‐risk babies. Removing parity would simplify the customised definition of SGA and would eliminate the need for the assumption that lower birthweight for primiparous women is normal.