Skip to main page content
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

Https

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
. 2012 Jul 4;2(4):e001152.
doi: 10.1136/bmjopen-2012-001152. Print 2012.

Cause-specific infant mortality in a population-based Swedish study of term and post-term births: the contribution of gestational age and birth weight

Maria Altman  1 , Anna-Karin Edstedt Bonamy, Anna-Karin Wikström, Sven Cnattingius
Affiliations

Cause-specific infant mortality in a population-based Swedish study of term and post-term births: the contribution of gestational age and birth weight

Maria Altman et al. BMJ Open. .

Abstract

Objective: To investigate infant mortality and causes of infant death in relation to gestational age (GA) and birth weight for GA in non-malformed term and post-term infants.

Design: Observational, retrospective nationwide cohort study.

Setting: Sweden 1983-2006.

Participants: 2 152 738 singleton non-malformed infants born at 37 gestational weeks or later.

Main outcome measures: Infant, neonatal and postneonatal mortality and causes of infant death.

Results: Infant mortality rate was 0.12% (n=2687). Compared with infants born at 40 weeks, risk of infant mortality was increased among early term infants (37 weeks, adjusted OR 1.70, 95% CI 1.43 to 2.02). Compared with infants with normal birth weight for GA, very small for gestational age (SGA; <3rd percentile) infants faced a doubled risk of infant mortality (adjusted OR 2.13, 95% CI 1.80 to 2.53), and corresponding risk was also increased among moderately SGA infants (3rd to <10th percentile; adjusted OR 1.46, 95% CI 1.26 to 1.68). Sudden infant death syndrome (SIDS) was the most common cause of death, accounting for 39% of all infant mortality. Compared with birth at 40 weeks, birth at 37 weeks was associated with increased risks of death by infections, cardiovascular disorders, SIDS and malignant neoplasms. Very and moderately SGA were associated with increased risks of death by neonatal respiratory disorders, infections, cardiovascular disorders, SIDS and neuromuscular disorders. High birth weight for GA was associated with increased risks of death by asphyxia and malignant neoplasms.

Conclusion: Early term birth and very to moderately low birth weight for GA are independent risk factors for infant mortality among non-malformed term infants.

PubMed Disclaimer

Conflict of interest statement

Competing interests: None.

References

    1. Reddy UM, Bettegowda VR, Dias T, et al. Term pregnancy: a period of heterogeneous risk for infant mortality. Obstet Gynecol 2011;117:1279–87 - PMC - PubMed
    1. Zhang X, Kramer MS. Variations in mortality and morbidity by gestational age among infants born at term. J Pediatr 2009;154:358–62, 62 e1. - PubMed
    1. Mathews TJ, MacDorman MF. Infant mortality statistics from the 2007 period linked birth/infant death data set. Natl Vital Stat Rep 2011;59:1–30 - PubMed
    1. Pulver LS, Guest-Warnick G, Stoddard GJ, et al. Weight for gestational age affects the mortality of late preterm infants. Pediatrics 2009;123:e1072–7 - PubMed
    1. Ludvigsson JF, Otterblad-Olausson P, Pettersson BU, et al. The Swedish personal identity number: possibilities and pitfalls in healthcare and medical research. Eur J Epidemiol 2009;24:659–67 - PMC - PubMed