Frequency and factors associated with the utilization (curative and preventive) of oral health care services among pregnant women in Kinshasa, Democratic Republic of Congo

Study setting and design

This cross-sectional study was conducted in Kinshasa, the capital and largest city of the DRC, from March to May, 2021. The study included four health facilities, each representing an administrative district of the city of Kinshasa: (i) the Sino-Congolese Friendship Hospital (District of Tshangu), (ii) Saint Gabriel Hospital (District of Mont-Amba), (iii) the Libikisi Reference Hospital (District of Funa), and (iv) the Maternity of Kintambo general referral hospital (District of Lukunga). The four health facilities were selected based on the following criteria: they are secondary-level institutions, have a high rate of ANC attendance, and have operational stomatology departments.

The Saint Gabriel Hospital, with 100 beds and 198 agents, provides primary health care to all sections of the population of the city of Kinshasa, starting with the poor, by providing them with a quality care package at reasonable prices, and to combat poverty. It also contributes to the practical training of the many trainees it receives [23]. The Kintambo general referral hospital, as defined by the Ministry of Public Health’s organic framework for general referral hospitals in health zones, provides a comprehensive range of healthcare services, including curative, preventive, promotional, and rehabilitative care for patients, as well as teaching and research activities [24]. The Sino-Congolese Friendship Hospital’s mission is to provide comprehensive care for patients, with a particular focus on those from Tshangu. Additionally, this 214-bed hospital aims to reduce the number of Congolese patients seeking care abroad, facilitate training for medical professionals, and engage in knowledge exchange with other medical training programs and the Chinese medical mission [25]. The Libikisi Reference Hospital is a private health facility owned by the Evangelical Mission of the Baptist Community of Congo. The facility has a total of 38 beds and an average of 150 consultations per day [26].

Participants

This study included all pregnant women who attended ANC services at the selected health facilities during the study period. The inclusion criteria were pregnant women who: (i) were at least 18 years old, (ii) attending ANC services at the time of data collection, and (iii) provided informed consent to participate in the study. However, pregnant women who were seriously ill or had a history of mental disorders were excluded from the study.

Sampling procedures

The sample size was calculated using the following formula:

where p = estimated proportion of pregnant women using oral and dental services in Kinshasa (50% = 0.5); q = 1-p = 0.5 (proportion of pregnant women who do not use oral and dental services); d = degree of absolute precision desired: 0.05 (d = 5%); α = error of the first type: 0.05; Z_α/2 = 95% confidence coefficient (1.96)²; n = minimum sample size. The required number for the largest sample size was 384, and 10% of the total sample size was added to compensate for the non-response rate. Finally, 500 pregnant women were included.

The sample was allocated proportionally to the average number of pregnant women who had received ANC in each health facility during the two months preceding the data collection period: Sino-Congolese Friendship Hospital (n = 65), Saint Gabriel Hospital (n = 131), Libikisi Reference Hospital (n = 107), and Maternity of Kintambo general referral hospital (n = 197). The participants at each health facility were selected using a simple random sampling technique until the required sample size at each health facility was obtained.

Data collection

A structured questionnaire was used to collect data from pregnant women during ANC sessions. The questionnaire was initially developed in French and subsequently translated into the local language “Lingala” for non-native French speakers. Four interviewers, selected in advance and trained by the principal investigator in the methodology and use of the questionnaire, conducted the face-to-face interviews with pregnant women. The questionnaire was developed based on the findings of several other studies on pregnant women’s utilization of oral health care services [1, 7,8,9]. It contained information regarding the following variables of interest:

• Socio-demographic status: age, education level, marital status, and parity.

• Socio-economic status: wealth index derived from a range of household assets (radio, television, landline telephone, personal computer, freezer, range cooker, furnaces, bed, sewing machine, clock, hoes, and house rental), housing conditions (availability of electricity and lamps), ownership of a means of transport (bicycle, motorcycle, and car), farmland, and domestic animals. The study participants were categorized based on their wealth index score, which was divided into quintiles of economic well-being [27].

• Knowledge of the relationship between oral health and pregnancy: the need of an oral consultation during pregnancy, awareness of the feasibility of dental care during pregnancy, importance of prevention and treatment of oral diseases by the dentist, relationship between oral health and the outcome of pregnancy, and relationship between hormonal changes during pregnancy and oral health.

• Oral health practices: tobacco use, alcohol use, frequency of tooth brushing, use of fluoride toothpaste when brushing, use of toothbrush for oral hygiene, duration of toothbrush use, and use of dental floss or interdental brush.

• Oral health status: gum bleeding, tooth decay, onset of perceived tooth decay, experience of dental pain or inflammation during the current pregnancy, difficulty chewing food, and oral health status since the onset of the pregnancy.

• Utilization of oral health care services:

• Status of oral health care utilization

• Reasons for utilization of oral health care services: reason for using oral health care services during pregnancy, oral problems motivating the utilization of oral health care services, pregnancy term during the oral health consultation, and management carried out during the oral health consultation.

• Reasons for non-utilization of oral health care services: cost of dental care, difficulty of movement, distance to the dental clinic, fear of complications with the pregnancy, lack of time, and no need for oral care during pregnancy.

To ensure the consistency and validity of the questionnaire, a pre-test was carried out on 5% of the final sample size in an environment similar to that of the present study. This was done by selecting pregnant women attending ANC services in a health facility on the outskirts of Kinshasa. Any necessary corrections were then made before the actual data collection by means of a structured interview.

Before collecting the data, we obtained authorization from the management of the selected health facilities and the administrative authorities of the localities hosting the survey sites. Pregnant women were then interviewed after the ANC visit, to ensure confidentiality. Interviews were only conducted with participants who had given verbal informed consent to participate in the study.

Operational and term definitions

• Utilization of oral health care services: having consulted with an oral health care professional at least once since the start of the current pregnancy.

• Oral health knowledge: the ability to access, comprehend, and utilize fundamental oral health information and services to make well-informed decisions about their own oral health.

• Oral health awareness: concern and informed interest in oral health care.

Data processing and analysis

The data collected were transcribed using an Epi-Data version 3.1 data entry mask. The generated database was exported to Microsoft Excel version 10 prior to cleaning, preliminary data processing, and analysis using R version 4.2.0.

Univariate analyses were performed to obtain descriptive statistics for the variables of interest, such as frequency and percentage (%) for the qualitative variables, and mean and standard deviations for the quantitative variable (age). Binary logistic regression analysis was employed to ascertain the factors associated with the utilization of oral health care services among pregnant women. The latter was designated as the dependent variable, with a value of 0 indicating no use and a value of 1 indicating use. All independent variables with p value < 0.20 in the bivariate logistic regression were considered as candidate factors for the subsequent forward stepwise multivariable model. The results were presented in the form of crude odds ratios (COR) and adjusted odds ratios (AOR), accompanied by their respective 95% confidence intervals (95% CI). Associations were considered statistically significant when the p value was less than 0.05. Multi-collinearity between the independent variables was assessed using the Variance Inflation Factor (VIF). Furthermore, the final model was evaluated for its fitness using the Hosmer-Lemeshow goodness-of-fit test.