Study design and setting
The current study analyses are part of the study titled “A Pilot Study of Improving Outcomes in Teenage Pregnancy Using a Combined Tailored M- Health Program and Motivational Interviewing Intervention” with trial registration number PACTR201912734889796. In this study, pregnant adolescents and young women were recruited to be enrolled in a pilot randomised controlled trial (RCT) that tested a behavioural intervention to improve their health care seeking and general health behaviours during pregnancy. Data were collected at baseline upon being recruited into the study as well as at follow-up after giving birth. This study reports on the baseline data which was collected during May – December 2018. A cross-sectional study design was used in the baseline survey. The study follows the STROBE Statement for reporting observational studies [27]. A sample of 200 (100 participants per group) was decided upon for the pilot RCT. However, given the high expected drop-out rate in adolescent public health longitudinal studies and that participants with missing information on contact details and pregnancy characteristics would be excluded from registration onto the mobile intervention, it was decided to recruit three times the planned sample size for the baseline survey.
In the South African primary healthcare system, which serves the majority of the population, pregnant girls and women receive antenatal care and maternity services at outpatient clinics, community health centres (CHC) or Midwife Obstetric Units (MOUs). The study was conducted in Cape Town in the Western Cape province of South Africa, which is predominantly urban. In 2019/20, 9.5% of the 67 485 in-facility deliveries in Cape Town were among adolescents aged 10-19 years. This was slightly lower than the 13.2% national adolescent in-facility delivery rate [12].
Recruitment of participants
Pregnant women and girls aged 13-20 years were eligible to be included and were recruited to participate in this study. Recruited women and girls who did not consent to participation were excluded from the study. Discussions were held with the Western Cape Provincial Department of Health to identify priority areas and clinics from which to recruit pregnant girls and young women. Based on these discussions, 16 community facilities that provided ANC (comprising public health clinics, CHCs and MOUs) were identified from which to recruit participants. These facilities were located in four of the eight health sub-districts in Cape Town; namely, Cape Town Eastern, Cape Town Northern, Mitchells Plain and Tygerberg. Participants were recruited while attending ANC at the facilities. Facility managers were contacted to inform them about the study and to engage them in discussions about recruitment and data collection activities. Researchers introduced the study to the ANC attendees in the waiting areas. In some cases, facility staff referred the researchers to groups of potential participants. Participants were also recruited from communities through social networks. The research assistants explained the study to potential participants in their language of choice. The research assistants were fluent in English, and either Afrikaans or isiXhosa, which are the three predominant official languages spoken in Cape Town.
Questionnaire development and data collection
Questionnaire development was guided by the RAA [25] and the I-Change model for understanding health behaviour [28]. The questionnaire items were informed by a literature review that identified psychosocial and socioeconomic factors associated with ANC attendance behaviours in young women and adolescents. The key thematic areas in the questionnaire were demographic characteristics, previous pregnancies, mental health status, knowledge of HIV and TB, knowledge regarding appointment attendance, risk perceptions; peer, partner and family support and attitudes regarding appointment attendance, and participant attitudes, self-efficacy and intention towards attending ANC appointments. The questionnaire was developed in English and then translated and back-translated into Afrikaans and isiXhosa by post graduate students proficient in each language who were working as part of the study’s research term.
Twenty research assistants were trained in recruitment and data collection activities and were selected to work in the study. Participants completed a self-administered structured questionnaire on an electronic tablet or mobile phone. The interviews were facilitated by the research staff. In a few cases where the participant was not comfortable with completing the questionnaire themselves, the research assistant administered the questionnaire. While the questionnaire was available to complete in Afrikaans, isiXhosa and English, only two participants opted to answer the questionnaire in Afrikaans and none in isiXhosa. Participants received a R50 (approx. $3) incentive upon completion of the questionnaire. The questionnaire took on average 60 minutes to complete.
Measures
The two dependent variables in this study were intention and self-efficacy to attend ANC appointments. Intention was measured by the item “I intend to attend all the clinic appointments” and self-efficacy was measured by the item “I am confident in my ability to attend clinic appointments, when I am feeling lazy and tired”. Both items were measured on a 4-point Likert scale, where 1=Strongly disagree, 2=Disagree, 3=Agree, and 4=Strongly agree. Hence, higher scores on the items indicated higher intention and self-efficacy to attend appointments.
The independent variables were classified into six groups i) risk perceptions, ii) social support from family, friends and partners for attending ANC, iii) partner attitudes regarding ANC, iv) peer attitudes and norms regarding ANC, v) family attitudes regarding ANC, and vi) participant attitudes regarding attending ANC. Seven items assessed risk perceptions regarding the implications of not attending or missing ANC appointments and the risks of pregnancy complications, with response options 1=Strongly disagree, 2=Disagree, 3=I don’t know, 4=Agree and 5=Strongly agree. Social support for attending ANC was assessed by three items regarding the encouragement received from each of family, friends and partner/boyfriend to attend ANC appointments, and response options were 1=Strongly disagree, 2=Disagree, 3=Agree, and 4=Strongly agree. Four items assessed partner/boyfriend attitudes regarding ANC attendance. Five items assessed the attitudes regarding ANC attendance among the participants’ friends who were or had been pregnant and one item assessed the norms regarding ANC attendance among the participants’ friends who were or had been pregnant. Response options for partner attitudes, peer norms and peer attitudes were 1=Strongly disagree, 2=Disagree, 3=Agree, and 4=Strongly agree. Participants who did not have a partner/boyfriend or did not have friends who had been pregnant did not answer the respective questions. Seven items assessed family attitudes regarding ANC attendance with response options 1=Strongly disagree, 2=Disagree, 3=I don’t know, 4=Agree and 5=Strongly agree. Thirteen items assessed participants’ attitudes regarding attending ANC, with response options 1=Strongly disagree, 2=Disagree, 3=I don’t know, 4=Agree and 5=Strongly agree. Therefore, the risk perception, family attitude and participant attitude items were assessed on a 5-point Likert scale while the social support, partner attitude and peer attitude and norm items were assessed on a 4-point Likert scale. The individual sub-determinant items included in the study are presented in Additional file 1.
Sociodemographic characteristics of the participants included date of birth, estimated date of delivery (EDD), estimated last menstrual date (or month), population group, type of residence, school or college attendance and previous pregnancies. Gestational age (number of weeks pregnant) was calculated using the EDD. When the participant did not know their EDD the last menstrual date was used instead. Age was calculated from the date of birth.
Statistical analysis
Data analyses were conducted using R version 4.0.3 and the Statistical Package for Social Sciences (SPSS) version 27. Data was collected from 615 participants, of which 575 (93.5%) answered the questions on intention and self-efficacy. Descriptive statistics of the sociodemographic characteristics were presented as means for interval variables and proportions for nominal variables. Confidence Interval Based Estimation of Relevance (CIBER) analysis [26] was conducted to assess the relevance of the psychosocial sub(determinants) (knowledge, risk perception, social support; peer, family, and partner attitudes and participant attitudes) of the intention and self-efficacy to attend ANC appointments.
CIBER is a data visualization method that uses a diamond plot to assess the most relevant sub-determinants for intervention development. It visualises the mean of each sub-determinant, its correlation with one or more determinants, and the confidence intervals of both these estimates. The diamond plot is divided into a left- and right-hand panel with diamond shapes. The question that assessed each sub-determinant with its anchors (highest and lowest response options on the Likert scale) is shown on the left of the left-hand panel. Each diamond shape in the left panel shows the mean of each sub-determinant item and its 99.99% confidence interval. Diamond shapes facilitate representation of the mean and the confidence interval in one shape. Generally, the redder the diamonds are the lower the item means and the greener the diamonds are the higher the item means. The dots around the left-hand panel diamonds show all the participants’ item scores with jitter added to prevent overplotting.
Each diamond in the right panel shows the correlation between the sub-determinant items and the two dependent variables (self-efficacy and intention) with their 95% confidence intervals. Purple diamonds represent the correlations of the sub-determinants and self-efficacy to attend ANC appointments when feeling lazy and tired. Yellow diamonds represent the correlations of the sub-determinants and the intention to attend all the ANC appointments. The fill colour of the diamonds indicates the strengths and directions of association – the redder the fill colour of the diamonds are, the stronger and more negative the correlations are; the greener the diamonds are, the stronger and more positive the correlations are; and the greyer the diamonds are, the weaker the correlations are. At the top of the plot is the confidence interval of the explained variance (R2) of self-efficacy and intention based on all items included in the plot. A CIBER plot was produced for the items relating to knowledge, risk perception, social support, family attitudes, peer and partner attitudes, and participant attitudes. The combination of correlation coefficients, means, and their confidence intervals were then interpreted to identify the relevant items that could be targeted in an intervention. Items that have low or mid-level means in the undesirable direction and have strong associations with the determinants of intention and self-efficacy are considered relevant sub-determinants for intervening upon.