The Second-Hand Smoke in Pregnancy and Its Impact Toward Low Birth Weight in District of Aceh Besar, Aceh Province, Indonesia

Background

Tobacco smoke exposure poses risks not only to active smokers but also to non-smokers in their vicinity — a phenomenon known as second-hand smoke (SHS) or passive smoking. Pregnant women who are exposed to SHS face elevated risks of adverse birth outcomes, including low birth weight (LBW), preterm delivery, miscarriage, and stillbirth. LBW, defined as birth weight below 2,500 grams, is a leading cause of neonatal morbidity and mortality in developing countries.

Indonesia has one of the highest male smoking rates in the world, exceeding 65% in many provinces. In the Aceh province, cultural norms around male smoking create environments where pregnant women are routinely exposed to tobacco smoke at home. This study investigated the impact of SHS exposure during pregnancy on birth weight outcomes in the district of Aceh Besar.

Study Design

A case-control study was conducted with 120 neonates: 60 LBW cases (birth weight below 2,500 grams) and 60 normal weight controls, matched on a 1:1 ratio. Data were collected using structured questionnaires completed by parents, covering maternal demographics, knowledge about smoking hazards, attitudes toward smoking, and exposure to SHS during pregnancy. Univariate analysis used percentages, and bivariate analysis employed the Wald-Wolfowitz runs test.

Knowledge, Attitudes, and Exposure

A notable finding was the disconnect between knowledge and cultural attitudes. While 75.8% (91 mothers) demonstrated good knowledge about the dangers of smoking, 60.8% (73 mothers) held positive attitudes toward male smokers — viewing men who smoke as exhibiting normal and socially acceptable behaviour. All 100% of mothers in the study were non-smokers themselves, consistent with the near-zero female smoking rate in Aceh’s conservative Muslim society.

Despite their non-smoking status, many mothers experienced substantial SHS exposure from husbands, fathers, and other male household members who smoked inside the home. The pervasive nature of indoor smoking in Indonesian households means that pregnant women often lack the social authority or physical means to avoid exposure, even when they understand its risks.

Association With Low Birth Weight

The study found that SHS exposure during pregnancy was associated with an increased likelihood of LBW delivery. This finding aligns with a substantial body of international evidence. A meta-analysis of nine studies from multiple countries found that cigarette smoke exposure during pregnancy increased the risk of LBW with an adjusted odds ratio of 2.19 (95% CI: 1.58–3.03). Data from the Indonesian Demographic and Health Survey 2017, encompassing nearly 20,000 mothers, showed that 78.4% were exposed to SHS inside the home, with LBW occurring in 7.2% of exposed versus a lower proportion in non-exposed mothers.

The biological mechanism is well-established: nicotine and carbon monoxide from tobacco smoke cross the placental barrier, impairing cytotrophoblast differentiation and proliferation, reducing uteroplacental blood flow, and creating a pathological hypoxic environment in the womb. These effects are dose-dependent, with daily exposure carrying the highest risks.

Public Health Implications

The findings underscore the urgent need for tobacco control strategies that address indoor smoking in the presence of pregnant women. In Indonesia’s cultural context, where male smoking is deeply normalised, interventions must go beyond individual-level health education to address the social and cultural determinants of smoking behaviour. Spouse-based educational interventions, smokefree home policies, and community-level campaigns that frame SHS exposure as a child protection issue rather than a personal choice may be more effective than traditional approaches.

The WHO recommendations for the prevention of tobacco use and SHS exposure in pregnancy (2013) provide an evidence-based framework that Indonesian health authorities can adapt to the local context. Health workers at the puskesmas (community health centre) level are well-positioned to screen for SHS exposure during antenatal visits and to provide brief counselling to both mothers and their partners.

Limitations

The study relied on self-reported questionnaire data, which may underestimate true SHS exposure due to social desirability bias or poor recall. Without biochemical verification (such as cotinine levels in maternal blood or cord blood), the degree and duration of SHS exposure cannot be precisely quantified. The case-control design is subject to recall bias, and unmeasured confounders — including maternal nutrition, anaemia, and gestational infections — may have influenced outcomes. The relatively small sample size limits statistical power for detecting modest effect sizes.

← Back to MJPHM Homepage