الفهرس 
INTRODUCTIONOnly 14 pages are availabe for public view
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Abstract
The theory of fetal origins of adult diseases states that some intrauterine exposures can affect the programming of fetal cells and this is presented by health consequences either at birth or later in life. Environmental tobacco smoke has been proved to be one of these exposures that can influence the fetal development and also the post-natal life.
The gestational period and birth outcomes are considered as crucial determinants of infant`s health and survival for years. Globally, 2.6 million infants die in the neonatal period every year. In 2015, Egypt was one of the 20 countries with the highest number of neonatal mortalities. Prematurity was the leading cause of neonatal death constituting 35% of all causes of neonatal death and congenital anomalies account for 11% of neonatal death. Low birth weight infants constituted 16% of total birth each year (22 million). In 2013, adverse birth outcomes, including low birthweight, small for gestational age (SGA), and preterm birth, contributed to 60%–80% of infant mortality worldwide.
The risk factors for adverse birth outcomes can be either genetic factors, infant related factors, parental factors, or environmental factors. Genetic factors can be determined by family history and presence of adverse birth outcomes in older siblings. Infant related factors include male gender, cesarean delivery, multiple gestation, and presence of any adverse birth outcome that can predispose to other adverse outcomes. Parental factors include maternal socioeconomic state, maternal lifestyle; smoking, alcohol consumption and work-related factors like heavy physical work, maternal drug intake and toxic exposures, medical and obstetric history and lack of medical care during pregnancy, maternal malnutrition and disturbed mental health, and paternal factors. Environmental factors, like pesticides, heavy metals, organic solvents and environmental tobacco smoke.
Tobacco use is the number one preventable cause of death worldwide, contributing to 6 million deaths every year of them more than 890 000 individuals die as a result of exposure to ETS. Globally, 40% of children, 35% of female non-smokers, and 33% of male non-smokers are exposed to ETS. ETS exposure varies widely by country and has a strong socioeconomic gradient, with lower socioeconomic status children having the highest ETS exposure. In Egypt, half of women and half of children are exposed regularly to environmental tobacco smoke from a household member within the dwelling and 53% of women in Egypt exposed to ETS at work.
It is proved that environmental tobacco smoke exposure is associated with deleterious health effects either in adults or in children. In adults, there is a causal relationship between ETS exposure and cardiovascular diseases, COPD, recurrent asthmatic attacks, lung cancer and urothelial carcinoma. In children, ETS exposure is associated with SIDS, various respiratory diseases, neurodevelopmental and psychomotor disorders, obesity, and malignant disorders specially childhood leukemia. Exposure of pregnant women in particular to ETS harbors adverse impacts on the growing fetus including adverse birth outcomes and even affects the future development during childhood and adult life.
The present study aimed at studying the association between exposure to ETS during pregnancy and adverse birth outcomes in Damanhur, El Behera governorate, in order to determine the prevalence of environmental tobacco smoke exposure among pregnant women, the prevalence of adverse birth outcomes, and to recognize the relationship between environmental tobacco smoke exposure during pregnancy and adverse birth outcomes.
In order to fulfill this aim, this cross-sectional study was conducted in Damanhur National Medical Institute (DNMI) in Damanhur, El Behera Governorate. The study Population included all admitted mothers in the postnatal ward of the obstetrics & gynecology department at DNMI, giving birth to viable single neonates with or without adverse birth outcomes (e.g., preterm birth, low birth weight, or congenital anomaly). Smoker mothers, parents with history of consanguinity, mothers with chronic medical conditions, and mothers reporting family history of genetic diseases were excluded from the study.
A pre-designed pre-coded structured interviewing questionnaire was used to collect data from the mothers including socio-demographic characteristics of the mothers, medical, gynecological and obstetric history of the mothers, detailed information on environmental tobacco smoke exposure status at home, in the workplace, in public places and in transportation means, medical history of the neonates and any birth complications. Neonatal birthweight, length and head circumference and maternal height and weight were also measured.
Appropriate statistical procedures were then applied to process the data and the following results were then obtained:
1. The percentages of all the adverse pregnancy outcomes among the sample was 29% of all newborns. Low birth weight was the most prevalent adverse birth outcome constituting about 23% of all newborns. It can be further classified into term low birth weight (62.5 % of all LBWs) and preterm low birth weight (37.5% of all LBWs).
2. Preterm birth was the second most common adverse birth outcome constituting about 11% of the total sample. About 9% of all newborns were small for gestational age, while large for gestational age and congenital anomalies constituted 3.5% and 0.87% respectively.
3. Regarding demographic data, significant differences were detected between mothers of normal neonates and mothers of neonates with adverse birth outcomes concerning paternal age, years of marriage, income sufficiency, and residence.
4. As regards maternal medical and obstetric parameters and its relation to adverse birth outcomes, maternal medical conditions (anemia/ hypotension) had significant association with adverse birth outcomes (X2=6.9, P=0.03). Moreover, pregnancy related problems (placental problems/ accidental hemorrhage) were significantly associated with adverse birth outcomes (X2=6.8, P=0.002, & X2=24.3, P=0.000) respectively. Primigravidae and primiparous women had significantly higher risk for having babies with adverse birth outcomes than multigravidas and multiparous (OR=1.58, 95% CI:1.01, 3.73) & (OR=1.87, 95% CI:1.09, 3.19) respectively.
5. Occupational exposure to chemical agents like organic solvents, insecticides and pesticides was significantly associated with adverse birth outcomes (X2=6.11, P=0.03), Also mothers who reported standing for long hours during work had 12.5 times more risk to have a baby with adverse birth outcomes than mothers who didn`t report standing for long hours (95% CI= 1.34-116.8).
6. With regard to environmental pollutants, there was a significant association between the use of cleaning products containing chlorinated solvents and the adverse birth outcomes (X2=3.99, P= 0.04), also there was a significant association between eating fish (which may contain heavy metals and PCBs) for 3 times per week or more and the adverse birth outcomes (X2=7.23, P=0.007).
7. Regarding maternal exposure to environmental tobacco smoke during pregnancy, the majority of the study sample (81%) reported exposure to ETS either at home, in the workplace, in transportation means or in public places. Regular exposure was reported in home and workplace exposed mothers constituting about 73% of the total sample. Mothers who reported regular exposure to ETS had two times more risk to experience adverse birth outcomes than mothers who reported no exposure (95% CI= 1.13-3.58).
8. About three quarters the mothers were exposed to ETS at home. According to the type of smoke, 65.7% were exposed to cigarettes and 16.5% were exposed to shisha. Exposure to ten cigarettes or more per day was significantly associated with more than two times risk of adverse birth outcomes. The risk increases with the increase in the number of cigarettes.
9. Home exposure to ETS was significantly associated with adverse birth outcomes (X2=5.13, P= 0.02). The source of ETS at home was either cigarettes, shisha or both. Mothers exposed to both cigarettes & shisha had the highest risk to have adverse birth outcomes (OR=2.57, 95% CI= 1.08-6.07) followed by those who were exposed to cigarettes alone (OR=1.89, 95% CI= 1.06-3.41). There was a dose dependent effect between the risk of adverse birth outcomes and the number of cigarette smokers at home and also the number of cigarettes smoked at home.
10. As regards exposure to ETS in the workplace, 26% of the working mothers in the study sample (19 working mothers) were exposed to ETS in their workplace. Exposure to ETS in transportation means was reported in 31.5% of the study sample & more than half of them (about 55%) reported exposure in the bus/ microbus. Regarding the frequency of exposure to ETS in transportation means (in hours), mothers who reported exposure for more than 20 hours in the whole current pregnancy had 5.35 times more risk for having adverse birth outcomes than mothers who reported exposure for less than 20 hours in the current pregnancy (95% CI= 1.19-24.03).
11. Concerning exposure to ETS in public places, 11% of the study sample reported exposure in public places & 60% of this exposure was in the markets. Exposure to ETS in public places was significantly associated with adverse birth outcomes (X2 =4.93, P=0.02).
12. There was a dose dependent effect between the number of sources from which mothers exposed to ETS (home, workplace, transportation means, or public places) and the risk for adverse birth outcomes (X2 for trend for OR =3.99, P=0.04).
13. Regarding the individual adverse birth outcomes, birth weight was the only birth outcome significantly associated with gestational exposure to ETS (t =3.23, P=0.001) and low birth weight was the adverse birth outcome most affected by ETS exposure (OR=2.74, 95% CI= 1.38-5.46). Gestational exposure to ETS was also associated with high risk of preterm birth (OR=1.36, 95%CI: 0.59-3.09) and small for gestational age (OR=1.97, 95%CI: 0.73-5.3) but these risks were not significant.
Based on the findings of this study, the following recommendations can be suggested:
- Preconception care, or antenatal care visits should include screening of all high risk through standardized questionnaires on environmental tobacco smoke exposures.
- Enrolling environmental tobacco smoke topic and its health effects in the health education sessions that pregnant women have during antenatal care visits.
- Routine screening for urinary cotinine level in pregnant women as a non-invasive method indicating ETS exposure which is a prevalent environmental contaminant with deleterious effects on birth outcomes.
- Implementation of legislations banning smoking in public places, public transportation, and in workplaces and enforcement of strict penalties on the outlaws.
- Epidemiologic studies that explore environmental exposures in general and environmental tobacco smoke in particular and their association with adverse birth outcomes in Egypt are needed. These studies should be improved to include epigenetic impacts and biological markers for better understanding of the pathophysiology of the environmental origin of different diseases.
In conclusion, Egypt has one of the highest rates of tobacco consumption levels in the Eastern Mediterranean region. With the weak enforcement of the tobacco control laws, more women and children are involuntarily exposed to environmental tobacco smoke. Gestational exposure in particular carries triple risk; for the mother herself, for the fetus affecting the intrauterine development, and for the infant during his postnatal period and later in life. Hence, we should spare no effort to protect this vulnerable group and provide a healthy environment for the children to grow in.