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Background

Low birth weight (LBW) is considered as a major multifaceted public health concern. Seventy-two percent of LBW infants are born in Asia.

An estimation of 8% LBW infants has been reported for Eastern Mediterranean region including Iran. This study investigated contributory factors of LBW in singleton term births in Tehran, Iran.

Tehran is a multicultural metropolitan area and a sample from the general population in Tehran could be regarded as a representative sample of urban population in Iran.

Methods

This was a retrospective study using data from 15 university maternity hospitals in Tehran, Iran.

Data on all singleton term births in these hospitals were extracted from case records during a one calendar year.

Study variables included: maternal age, maternal educational level, history of LBW deliveries, history of preterm labor, cigarette smoking during pregnancy, number of parities, chronic diseases and residential area (Tehran versus suburbs of Tehran).

In order to examine the relationship between LBW and demographic and reproductive variables the adjusted logistic regression analysis was performed.

Results

In all, data for 3734 term pregnancies were extracted.

The mean age of women was 25.7 (SD = 5.3) years and 5.2% of term births were LBW.

In addition to association between LBW and maternal age, significant risk factors for LBW were:

• history of LBW deliveries [adjusted odds ratio (OR) = 2.53, 95% confidence interval (CI) = 1.06–6.03],
• smoking during pregnancy (OR = 4.64, 95% CI = 1.97–10.95)
• and chronic diseases (OR for hypertension = 3.70, 95% CI = 2.25–6.06, OR for others = 2.04, 95% CI = 1.09–3.83).

Conclusion

The findings indicate that in addition to maternal age, history of LBW deliveries; smoking during pregnancy and chronic diseases are significant determinants of LBW in this population.

This is consistent with national and international findings indicating that maternal variables and risk behaviors during pregnancy play important roles on LBW.

Abstract

Background Methods Results Discussion Conclusion Abbreviations Competing interests Authors' contributions Pre-publication history References 

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INTRODUCTION

Low birth weight (LBW) is a reliable indicator in monitoring and evaluating the success of maternal and child health programs and has been defined as a birth weight less than 2500 gr [1].

It is estimated that worldwide 15.5% of all live births per year are LBW and more than 95 percent of LBW infants are born in developing countries.

Seventy-two percent of LBW infants are born in Asia, although large differences exist in WHO Asian regions and its sub-regions.

It is estimated that there are 8% of LBW infants in Eastern Mediterranean region including Iran [2].

A baby's low weight at birth is either the result of preterm birth or of intrauterine growth retardation (IUGR) [2].

The latter implies that fetus's growth has been inhibited and thus the fetus has not attained the potential growth.

The diagnosis of IUGR is usually based on small size for gestational age (SGA).

However, IUGR is not completely equal to SGA and there is need to develop standardized and population-specific growth charts to well differentiate these clinical terms in practice [3].

The evidence suggests preterm birth as a main cause of newborn mortality and morbidity [4].

Indeed, LBW due to IUGR as a poor birth outcome affects the person throughout life course and is associated with a higher risk of developmental impairments including cognitive development [5], medical and health outcomes in adulthood [6,7].

Giving birth to a LBW infant is influenced by several determinants including maternal variables [8-10], socio-economic status [11] and environmental factors [12].

This study investigated the contribution of socio-demographic and reproductive-obstetrical risk factors on LBW in all singleton term births that referred from Tehran and its suburbs to the main general and teaching hospitals in Tehran during a one calendar year (2005).

BMC Pregnancy Childbirth. 2008; 8: 12.

Mariam Vahdaninia,¹ Sedigheh Sadat Tavafian,¹ and Ali Montazeri¹

¹Iranian Institute for Health Sciences Research, Tehran, Iran

Corresponding author.

• Mariam Vahdaninia: vahdaninia@acecr.ac.ir
• Sedigheh Sadat Tavafian: stavafian@ihsr.ac.ir
• Ali Montazeri: montazeri@acecr.ac.ir 

This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

SEE FULLTEXT

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