South Africa, being one of the first countries to put into place strict laws, which limited SHS exposure in public places, should be benefiting from less of a burden of disease from smoking and SHS.
However, what about pregnant women in their homes and in the workplace? If there are high exposure rates, the women and unborn babies involved are at a significant risk for the negative health effects of SHS exposure. It is therefore important to obtain local data on SHS exposure rates in pregnancy, to inform further tobacco control measures with regard to home and workplace exposure by non-smokers. The pregnant population of Soweto, which is served by Chris Hani Baragwanath Maternity Hospital as its
pregnancy referral centre, seemed an ideal starting point to explore the extent of SHS exposure in South African pregnant women, to find out how pregnant women regard and deal with smoking in their immediate environment.
4. OBJECTIVES OF THE STUDY
1. To determine Soweto pregnant women’s exposure rate to SHS.
2. To describe the demographic characteristics of pregnant women exposed to SHS.
3. To describe, Soweto pregnant women’s knowledge, attitudes and practices regarding SHS exposure.
5. METHODS
5.1 Study design
This was a hospital-based, prospective, cross sectional study.
5.2 Study Setting
The study was carried out at Chris Hani Baragwanath Academic Hospital. This is one of the hospitals affiliated with the University of Witwatersrand and is situated in Soweto, South Africa. This hospital has a large number of deliveries (in excess of 23 000 per annum) and as a referral centre it delivers women with high-risk pregnancies, and also low-risk pregnancies transferred from Soweto clinics because of problems arising during antenatal care or in labour. About 10 000 low-risk births are conducted in seven clinics in Soweto, Orange Farm and Lenasia. In accordance with national guidelines on antenatal care, smoking in pregnancy is included in a check-list on the antenatal card, but SHS exposure is not recorded routinely on any document.
5.3 Study population
The study population was women aged 18 years and above who were delivered by primary caesarean section (no previous caesarean section) at Chris Hani Baragwanath Academic Hospital, as representing pregnant women from Soweto. There were two
reasons for choosing women who had primary caesarean sections: 1) they were
hospitalized for more than 48 hours after delivery and therefore provided the opportunity for interviews; and 2) women with primary caesarean sections are likely to reflect the overall population of pregnant women throughout Soweto.
The choice of women with primary caesarean section as the sample supposes that the risk of primary caesarean section is not related to SHS exposure. Choosing women after vaginal birth would have sampled mostly high-risk pregnancies having vaginal births in the referral unit at Chris Hani Baragwanath. High-risk pregnant women may modify their exposure to SHS. If the participants had had a previous caesarean section they would have been referred as high-risk for part of their antenatal care and therefore may have had received additional antenatal education including advice regarding smoking. This may have made them more careful in the pregnancy, in terms of self-education, and healthy practices, including avoidance of SHS. Sampling women with primary caesarean sections probably resulted in less selection bias than sampling women with hospital vaginal births. Salmasi et al. found from their meta analyses, there was no significant difference between pregnant women exposed to SHS and those who had a caesarean section (OR 1.10; 95% CI 0.88–1.39, four studies) [80]. Therefore, the data collected from the post-caesarean participants should not be viewed as a limitation of the study and be deemed an acceptable population sample to determine SHS smoke exposure rates.
Given the referral system in Soweto, it is impossible to avoid selection bias in choosing participants for community-based research from users of Chris Hani Baragwanath Academic Hospital for community-based research.
5.4 Inclusion criteria
Women over 18 years of age, who had a primary caesarean section.
5.5 Exclusion criteria
Participants would have previously had a caesarean section. All high risk pregnancies resulting from maternal or fetal causes were excluded. Examples of such exclusions were maternal medical conditions such as hypertension, diabetes, epilepsy, asthma or any other chronic medical conditions. Fetal intrauterine growth restriction diagnosed antenatally was also an exclusion criterion.
5.6 Sampling
Sampling was done in the postnatal caesarean section ward, which consists of 10 cubicles, each with six beds. Women were selected from the cubicles using bed
numbers, with the occupants of individual beds selected using a random number list. On days that the researcher was available to collect data, she started at the selected bed
and sampled in ascending number order from that bed until sufficient, eligible women had been selected and agreed to participate, as time permitted.
5.7 Sample size
The researcher interviewed 100 individuals who met the criteria of the study population.
This sample size gives 95% confidence intervals at most within ±10% of the observed sample percentage. The study was not powered to test hypotheses on factors
associated with SHS exposure.
5.8 Control group
A control group was not applicable to this study.
5.9 Data collection
A prospective questionnaire using a face-to-face interview was conducted on the
women who fulfilled the criteria (Appendix 1). A pilot study on 10 women was carried out to test the questionnaire. The researcher personally interviewed each participant. Three women were unable to answer the questions due to language and communication difficulties and declined the interview.
Questions included the pregnant woman’s demographic data, use of tobacco products and exposure to SHS in the household and at work. Where possible, questions were
used from pre-existing validated survey tools: Global Tobacco Surveillance System, Tobacco Questions for Surveys, A subset of Key Questions from the Global Adult Tobacco Survey [61], 2000 US National Health Interview Survey [97] and the Smoke-Free Families Screening Form [98]. Questions were also included from the Centers for Disease Control’s the health consequences of involuntary exposure to tobacco smoke:
a report of the Surgeon General, Atlanta, GA: 2006 [40]. Some of the questions were adapted from the study by Bloch et al [58] to assess pregnant women’s use of tobacco and SHS exposure and to allow for direct comparison to the nine developing nations’
pregnant women’s SHS exposure rate. The two most important questions asked were tobacco use status and SHS exposure.
5.10 Tobacco use status
Participants were asked, “have you ever tried cigarette smoking, even one or two puffs?” If the answer was “yes”, the participant was considered to have experimented with cigarettes. Following on from experimentation, questions were asked to determine if the participant was a regular smoker or had ever been a regular smoker. If she answered “yes” to smoking every day or to have smoked more than 100 cigarettes in her lifetime, the participant was considered to have been a regular smoker. To
determine if she was a current smoker, the participant was asked if she currently smoked cigarettes every day.
5.11 SHS exposure
All participants were asked, “how often are you indoors and around people who are smoking cigarettes or other types of tobacco products?”. Response options included always, frequently, sometimes, rarely or never. Those that responded with either always or frequently were considered to be exposed to SHS using the self-reporting method.
5.12 Data analysis
The data were entered onto a Microsoft Excel spreadsheet (Appendix 2), and then exported for analysis in Stata 11 software (Statacorp, College Station, Texas, USA).
With the assistance of a statistician within the department, descriptive statistics were performed using frequencies with percentages and 95% confidence intervals, means with standard deviations, and medians with ranges where appropriate.
Comparison of characteristics between groups employed the following techniques. For categorical data, the chi-squared test or Fisher’s exact test was used, whichever was appropriate. For continuous (numerical) data, Student’s t-test or Wilcoxon’s ranksum test was used, whichever was appropriate. Statistical significance was accepted at P<0.05.
5.13 Ethics
All participants were counselled about the reason for the study. Informed consent was obtained following the patient agreeing to the interview. Each participant was assured that all data collected would remain anonymous on the data sheets (Appendix 3).
Permission to conduct the study was sought from the University of the Witwatersrand’s Human Research and Ethics Committee (approval number M150503, Appendix 4) The designated representative of the Chief Executive Officer at Chris Hani Baragwanath Academic Hospital was approached for permission to conduct the study. Permission was granted (Appendix 5).