Application of problem-based learning and case-based learning in teaching ectopic pregnancy to fifth-year medical students
According to the Centers for Disease Control and Prevention, ectopic pregnancy accounts for approximately 2% of all reported pregnancies . Despite improvements in diagnosis and management, ruptured ectopic pregnancy continues to be a significant cause of pregnancy-related mortality and morbidity . Ectopic pregnancy is an acute complex condition. Therefore, reforming the teaching method for ectopic pregnancy, cultivating students' logical thinking, and leading students to obtain better learning results in a limited time have become urgent problems to be solved. Traditional teaching methods do not allow medical students to combine their theoretical and practical knowledge. As a traditional teaching method, lecture-based learning (LBL) adopts an “indoctrination” teaching method, taking teachers as the teaching center, students passively accepting knowledge, which medical students and teachers widely accept, and evidence suggests that LBL is easy to implement, but insufficient for the acquisition of knowledge and can lead to the students’ negligence . Problem-based learning (PBL) is a student-centered and question-based education method in which participants are allocated to groups of up to eight under the guidance of teachers and assigned tasks or challenges that reflect situations relevant to the working environment they are anticipated to experience . Case-based learning (CBL) is a case-oriented and student-centered educational method grounded in the analysis of medical records to restore real clinical scenes and prompt students to identify and develop new areas of learning . However, when used individually, both PBL and CBL have some limitations . CBL requires teachers to dedicate time to preparing a sufficient number of cases to support clinical teaching. At the same time, CBL requires teachers to create a set of questions for students to discuss, and lacks flexibility, leading to a lack of initiative and general enthusiasm for the learning experience. In contrast, PBL places the student at the center, playing a leading role in the classroom process. Given their heavy curriculum tasks and commitment, this function requires them to spend considerable time preparing questions and materials before class, which is extremely difficult for medical students. In addition, PBL emphasizes students' subjective initiatives; however, the lack of guidance from teachers could lead to students missing the program focus, which could affect the course's overall quality. Since PBL is primarily student-driven, whereas CBL is collaborative , we hypothesize that PBL and CBL are mutually complementary and that a combined PBL-CBL teaching method can better promote effective, high-quality student learning. Furthermore, few studies have found that this model has obvious advantages over traditional teaching methods . At present, the teaching mode of ectopic pregnancy is mostly the traditional teaching method. In this study, we combined PBL with the CBL for the clinical teaching of ectopic pregnancy. Additionally, we assessed whether the combined PBL-CBL teaching method could compensate for the inadequacy of traditional teaching methods by improving the learning interest and enhancing the understanding of ectopic pregnancy among fifth-year medical students.   Participants This prospective randomized controlled study included 80 fifth-year students majoring in clinical medicine from the Department of Gynecology at Hengyang Central Hospital (20 students) and Hainan General Hospital (60 students) between September 2023 and June 2024. The students were randomly assigned to either the combined PBL-CBL group, which featured a combined PBL-CBL teaching method, or the traditional group, which featured a traditional LBL teaching method. An independent statistician prepared a randomization table using SAS software (SAS Institute, Cary, NC, USA), and the study participants were assigned using a simple randomization method. Neither the students nor teachers were aware of the group information before class. This study was approved by the hospital’s institutional ethics committee. Written informed consent was obtained from all the participants. Study design The schedule for the combined PBL-CBL group was as follows: before each lesson, the teacher prepared lecture videos, typical clinical cases, and reference papers related to the course topic. The students were required to review these materials during their spare time outside of class. Before beginning the course, the teacher briefly introduced the topic and the class agenda, after which, under the teacher’s guidance, the students conducted small group discussions. Each group was assigned specific learning tasks such as reviewing relevant literature, analyzing cases, and making treatment plans. During these discussions, the students were encouraged to raise relevant questions and seek answers on the Internet and library databases. After each learning group completes the learning task within a certain period, they can present their learning results to all the students and teachers through posters or presentations. The schedule for the traditional group was as follows: before the lecture, the students were instructed to preview the course instead of watching videos or reading materials. The students learned the same content using traditional teaching methods. The teacher systematically taught the concept, etiology, clinical manifestations, diagnosis, differential diagnosis, and treatment of ectopic pregnancy. In other words, teacher-centered instruction was the predominant method. Data evaluation and statistical analysis At the end of the class, both groups of students were required to complete a post-class quiz and an anonymous questionnaire. The quizzes comprised basic theoretical questions (each worth 50 points) and clinical case analyses (each worth 50 points). The anonymous questionnaire comprised nine questions about learning motivation, understanding, student–teacher interaction, how much free time the course consumed, communication skills, clinical thinking skills, self-learning skills, knowledge absorption, and satisfaction. The evaluation criteria were based on literature research  and expert interview guidance. The scores were divided into five grades based on improvement from 1 (poor) to 5 (excellent). In contrast to the other scored areas, 1 represented the lowest free time consumption, while 5 indicated the highest. In this study, Cronbach’s α was used to evaluate the reliability of the questionnaire with 20 students as the sample. The Cronbach’s α coefficient in each question was acceptable (α = 0.72–0.86). All the statistical analyses were performed using SPSS version 18 (IBM Corp., Armonk, NY, USA). Continuous data were reported as mean and SD when normally distributed, and median and interquartile range (IQR) when not normally distributed. Normally distributed continuous data were analyzed using Student’s t-test. The Mann–Whitney U test was used to analyze continuous data that were not normally distributed. The categorical data are reported as counts and percentages and were analyzed with χ2 and Fisher exact tests. All tests were two-sided, and p < 0.05 was considered significant.   This prospective randomized controlled study included 80 fifth-year students majoring in clinical medicine from the Department of Gynecology at Hengyang Central Hospital (20 students) and Hainan General Hospital (60 students) between September 2023 and June 2024. The students were randomly assigned to either the combined PBL-CBL group, which featured a combined PBL-CBL teaching method, or the traditional group, which featured a traditional LBL teaching method. An independent statistician prepared a randomization table using SAS software (SAS Institute, Cary, NC, USA), and the study participants were assigned using a simple randomization method. Neither the students nor teachers were aware of the group information before class. This study was approved by the hospital’s institutional ethics committee. Written informed consent was obtained from all the participants.   The schedule for the combined PBL-CBL group was as follows: before each lesson, the teacher prepared lecture videos, typical clinical cases, and reference papers related to the course topic. The students were required to review these materials during their spare time outside of class. Before beginning the course, the teacher briefly introduced the topic and the class agenda, after which, under the teacher’s guidance, the students conducted small group discussions. Each group was assigned specific learning tasks such as reviewing relevant literature, analyzing cases, and making treatment plans. During these discussions, the students were encouraged to raise relevant questions and seek answers on the Internet and library databases. After each learning group completes the learning task within a certain period, they can present their learning results to all the students and teachers through posters or presentations. The schedule for the traditional group was as follows: before the lecture, the students were instructed to preview the course instead of watching videos or reading materials. The students learned the same content using traditional teaching methods. The teacher systematically taught the concept, etiology, clinical manifestations, diagnosis, differential diagnosis, and treatment of ectopic pregnancy. In other words, teacher-centered instruction was the predominant method.   At the end of the class, both groups of students were required to complete a post-class quiz and an anonymous questionnaire. The quizzes comprised basic theoretical questions (each worth 50 points) and clinical case analyses (each worth 50 points). The anonymous questionnaire comprised nine questions about learning motivation, understanding, student–teacher interaction, how much free time the course consumed, communication skills, clinical thinking skills, self-learning skills, knowledge absorption, and satisfaction. The evaluation criteria were based on literature research  and expert interview guidance. The scores were divided into five grades based on improvement from 1 (poor) to 5 (excellent). In contrast to the other scored areas, 1 represented the lowest free time consumption, while 5 indicated the highest. In this study, Cronbach’s α was used to evaluate the reliability of the questionnaire with 20 students as the sample. The Cronbach’s α coefficient in each question was acceptable (α = 0.72–0.86). All the statistical analyses were performed using SPSS version 18 (IBM Corp., Armonk, NY, USA). Continuous data were reported as mean and SD when normally distributed, and median and interquartile range (IQR) when not normally distributed. Normally distributed continuous data were analyzed using Student’s t-test. The Mann–Whitney U test was used to analyze continuous data that were not normally distributed. The categorical data are reported as counts and percentages and were analyzed with χ2 and Fisher exact tests. All tests were two-sided, and p < 0.05 was considered significant.   From September 2023 to June 2024, 80 students were enrolled and randomly assigned to either the combined PBL-CBL group ( n = 40) or the traditional group ( n = 40). Basic student characteristics are shown in Table . The average age of students was 22.8 ± 0.7 years in the combined PBL-CBL group and 22.9 ± 0.7 years in the traditional group; the difference between the two groups was not statistically significant ( p = 0.765). Nineteen (47.5%) female students were assigned to the combined PBL-CBL group, and 21 (52.5%) to the traditional group; No significant difference was noted between the two groups in terms of gender. The average time spent on pre-class preparation was significantly longer in the combined PBL-CBL group than that in the traditional group (85.8 ± 5.8 vs. 69.3 ± 7.0 min, p = 0.000). Table presents the quiz scores. The basic knowledge score in the combined PBL-CBL group was significantly higher than that in the traditional group (42.6 ± 3.6 vs 35.0 ± 2.3, p = 0.000). Similarly, the case analysis score was higher in the combined PBL-CBL group than that in the traditional group (37.1 ± 6.2 versus 33.8 ± 5.7, p = 0.013). Accordingly, the total quiz score in the combined PBL-CBL group was higher than that in the traditional group (79.6 ± 6.9 versus 68.7 ± 5.7, p = 0.000). The results of the anonymous questionnaire are presented in Table . The scores for learning motivation, understanding, student–teacher interaction, communication skills, clinical thinking skills, self-learning skills, knowledge absorption, and satisfaction with the course in the combined PBL-CBL group were significantly higher than those in the traditional group ( p < 0.05 for all). However, the score for the amount of free time consumed in the combined PBL-CBL group was significantly higher than that in the traditional group ( p < 0.05).   Ectopic pregnancy is a potentially life-threatening condition and the leading cause of maternal mortality within the first trimester of pregnancy, with a rate of 9–14% and an incidence of 5–10% of all pregnancy-related deaths . Women with nonspecific symptoms such as lower abdominal pain and vaginal bleeding in the first trimester have an ectopic pregnancy prevalence in emergency departments as high as 18%, which can be easily misdiagnosed as many clinical mimics such as luteal rupture and acute appendicitis . Therefore, prompt and accurate diagnosis is of paramount importance, as early detection and treatment can decrease morbidity and mortality. Medical students have a short clinical learning cycle and a long interval between theoretical classes; therefore, it is very important for them to transition from theory to practice. Simultaneously, traditional teaching methods focus on teaching teachers while students passively receive theoretical knowledge. One limitation of this model is that teachers focus more on their understanding of the subject and do not play an effective role in guiding students to develop clinical thinking. In addition, several medical students lack initiative and creativity, which ultimately leads to difficulties applying what they have learned in clinical practice . Unlike traditional teaching methods, both PBL and CBL are new clinical teaching models that encourage students to take an active learning attitude, moving from a paradigm of "what I learn" to "what I want to learn" . Some studies have shown that the use of PBL or CBL alone has advantages over traditional teaching methods and has been described as a promising tool in medical education . Wang et al.  found that PBL and CBL have different emphases but that the combination of PBL and CBL can improve the academic achievement in oral education. Considering their respective advantages, our study applied a teaching method that integrates PBL and CBL in teaching ectopic pregnancy among fifth-year medical students, allowing them to complement and reinforce each other. To investigate the effectiveness and acceptability of the combined PBL-CBL teaching method in teaching ectopic pregnancy, we compared it to the traditional teaching method. Our study showed no significant differences in the basic characteristics between the two groups. However, after the end of learning, the combined PBL-CBL group scored higher than the traditional group on the total quiz, basic knowledge, and case analysis, demonstrating the effectiveness of the combined PBL-CBL teaching method. The results also indicated that students in the combined PBL-CBL group formed a comprehensive and organized understanding of ectopic pregnancy, which further enhanced their clinical thinking skills. Additionally, we assessed the students’ subjective perceptions and experiences and found that students rated the combined PBL-CBL teaching method highly in terms of learning motivation, understanding, student–teacher interaction, communication skills, clinical thinking skills, self-learning skills, knowledge absorption, and satisfaction with the course. These results also indicate that students in the combined PBL-CBL group tended to adopt a more balanced approach to learning and practice and obtained a higher satisfaction rate with the course, thereby becoming more proactive learners. This is consistent with the findings of previous studies . Zhao et al.  showed that a combined PBL-CBL teaching method can improve the performance of medical students and residents as well as their clinical skills and abilities when learning about thyroid nodules. Liu et al.  showed that, when teaching maxillary sinus floor augmentation in implant dentistry, the combined PBL-CBL method improved the academic knowledge acquisition, case analysis ability, and student satisfaction compared to the traditional teaching method. To the best of our knowledge, this study is the first to apply the PBL combined CBL teaching model to the clinical teaching of ectopic pregnancy. However, this study has some limitations. First, we assumed that PBL and CBL were mutually complementary and that they could achieve the best effect when combined. However, no control group used PBL or CBL alone in this study and we could not determine whether the combined method was superior to PBL or CBL alone. Second, some analytical biases were unavoidable because of the lack of blinding in our study. Third, our results are based on an ectopic pregnancy course with a small sample size. Long-term follow-up data were unavailable for a more grounded assessment. Therefore, more well-designed, randomized controlled trials with larger sample sizes are needed to confirm the effects of the combined PBL-CBL teaching method. In conclusion, this study showed that students learning ectopic pregnancy with the combined PBL-CBL teaching method exhibited better acquisition of basic knowledge and higher competence in case analysis than those learning ectopic pregnancy with traditional teaching methods. These results suggest that the combined PBL-CBL teaching method might be a promising new mode of gynecological education.   Supplementary Material 1.   