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. 2018 Aug 8:4:15.
doi: 10.1186/s40748-018-0084-2. eCollection 2018.

Recent trends, risk factors, and disparities in low birth weight in California, 2005-2014: a retrospective study

Anura W G Ratnasiri  1   2 , Steven S Parry  1 , Vivi N Arief  2 , Ian H DeLacy  2 , Laura A Halliday  3 , Ralph J DiLibero  1 , Kaye E Basford  2   4
Affiliations

Recent trends, risk factors, and disparities in low birth weight in California, 2005-2014: a retrospective study

Anura W G Ratnasiri et al. Matern Health Neonatol Perinatol. .

Abstract

Background: Low birth weight (LBW) is a leading risk factor for infant morbidity and mortality in the United States. There are large disparities in the prevalence of LBW by race and ethnicity, especially between African American and White women. Despite extensive research, the practice of clinical and public health, and policies devoted to reducing the number of LBW infants, the prevalence of LBW has remained unacceptably and consistently high. There have been few detailed studies identifying the factors associated with LBW in California, which is home to a highly diverse population. The aim of this study is to investigate recent trends in the prevalence of LBW infants (measured as a percentage) and to identify risk factors and disparities associated with LBW in California.

Methods: A retrospective cohort study included data on 5,267,519 births recorded in the California Birth Statistical Master Files for the period 2005-2014. These data included maternal characteristics, health behaviors, information on health insurance, prenatal care use, and parity. Logistic regression models identified significant risk factors associated with LBW. Using gestational age based on obstetric estimates (OA), small for gestational age (SGA), appropriate for gestational age (AGA) and large for gestational age (LGA) infants were identified for the periods 2007-2014.

Results: The number of LBW infants declined, from 37,603 in 2005 to 33,447 in 2014. However, the prevalence of LBW did not change significantly (6.9% in 2005 to 6.7% in 2014). The mean maternal age at first delivery increased from 25.7 years in 2005 to 27.2 years in 2014. The adjusted odds ratio showed that women aged 40 to 54 years were twice as likely to have an LBW infant as women in the 20 to 24 age group. African American women had a persistent 2.4-fold greater prevalence of having an LBW infant compared with white women. Maternal age was a significant risk factor for LBW regardless of maternal race and ethnicity or education level. During the period 2017-2014, 5.4% of the singleton births at 23-41 weeks based on OE of gestational age were SGA infants (preterm SGA + term SGA). While all the preterm SGA infants were LBW, both preterm AGA and term SGA infants had a higher prevalence of LBW.

Conclusions: In California, during the 10 years from 2005 to 2014, there was no significant decline in the prevalence of LBW. However, maternal age was a significant risk factor for LBW regardless of maternal race and ethnicity or education level. Therefore, there may be opportunities to reduce the prevalence of LBW by reducing disparities and improving birth outcomes for women of advanced maternal age.

Keywords: Advance maternal age; Health behavior; Low birth weight; Maternal health; Prenatal care; Preterm birth; Small for gestational age.

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Conflict of interest statement

The study was approved by the California Committee for the Protection of Human. Subjects (Protocol ID: 16–10-2759) and the California Department of Public Health Vital Statistics Advisory Committee. Patient consent was waived by the Human Subjects committee.Permission for publication was included when requesting approval from both California Committee for the Protection of Human Subjects (Protocol ID: 16–10-2759) and the California Department of Public Health Vital Statistics Advisory Committee. We are to provide published materials to both institutes.The authors declare that they have no competing interests.Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.

Figures

Fig. 1
Fig. 1
Unadjusted prevalence and adjusted odds ratios of low birth weight of singleton births by maternal age in California for the period 2005–2014
Fig. 2
Fig. 2
Unadjusted prevalence of low birth weight by maternal age and maternal race and ethnicity in California for the period 2005–2014
Fig. 3
Fig. 3
Unadjusted prevalence of low birth weight by maternal education level and maternal race and ethnicity in California for the period 2005–2014
Fig. 4
Fig. 4
Distribution of singleton births at 23–41 weeks of gestation with respect to birth weight and gestational age based on obstetric estimates (OE) in California for the period 2007–2014. SGA: small for gestational age; AGA appropriate for gestational age, LGA large for gestational age, LBW low birth weight (< 2500 g)
See this image and copyright information in PMC

References

    1. Battaglia FC, Lubchenco LO. A practical classification of newborn infants by weight and gestational age. J Pediatr. 1967;71:159–163. doi: 10.1016/S0022-3476(67)80066-0. - DOI - PubMed
    1. Malin GL, Morris RK, Riley R, Teune MJ, Khan KS. When is birthweight at term abnormally low? A systematic review and meta-analysis of the association and predictive ability of current birthweight standards for neonatal outcomes. BJOG. 2014;121:515–526. doi: 10.1111/1471-0528.12517. - DOI - PMC - PubMed
    1. Lee AC, Kozuki N, Cousens S, Stevens GA, Blencowe H, Silveira MF, et al. CHERG small-for-gestational-age preterm birth working group. Estimates of burden and consequences of infants born small for gestational age in low and middle income countries with INTERGROWTH-21st standard: analysis of CHERG datasets. BMJ. 2017;j3677:358. - PMC - PubMed
    1. Baer RJ, Rogers EE, Partridge JC, Anderson JG, Morris M, Kuppermann M, et al. Population-based risks of mortality and preterm morbidity by gestational age and birth weight. J Perinatol. 2016;36:1008–1013. doi: 10.1038/jp.2016.118. - DOI - PubMed
    1. Ray JG, Park AL, Fell DB. Mortality in infants affected by preterm birth and severe small-for-gestational age birth weight. Pediatrics. 2017; 10.1542/peds.2017-1881. - PubMed

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