Results of the present study revealed that the patients’ tendency toward TCM utilization increased as the follow-up time increased, whereas the patients’ tendency toward WM utilization decreased as follow-up time increased. The frequency of use, treatment of disease categories, and commonly prescribed Chinese herbal formulas of TCM have been surveyed in previous studies by analyzing the NHIRD [13, 14]. The present study focused mainly on the analysis of outpatient utilization and patterns in the presented gynecological diagnoses rather than the use of TCM prescriptions. TCM utilization was only 0.62 and WM utilization was 1.67 within 6 months after the first menstrual syndrome diagnosis. Unlike some other diseases, symptoms of menstrual discomfort occur frequently and periodically. For women who experience menstrual discomfort every month, the frequency of related medical care utilization is very low. A previous study showed that most women experience some menstrual discomfort but only a few will seek medical care [15, 16]. Participants in another study indicated that professional treatment was sought only if they felt the pain was too intense and unbearable [17]. It is reasonable to conclude that patients start looking for medical services when symptoms are more severe or unbearable [13]. TCM is widely used in Taiwan and other Asian countries. As part of complementary and alternative medicine, TCM, like WM, is a scientific system supported by a complete theory [18]. For better treatment results, the concept of TCM suggests the importance of constitutional adjustments, which typically take a long time. Once patients accept the concept of TCM treatment, they continue to return to the clinic for treatment, and the number of times is often more as time progresses than at the initial starting point. TCM is used most frequently by patients who would like to decrease recurrent symptoms and relieve the uncomfortable side effects of treatment [19]. In contrast, the WM approach places more emphasis on the immediate effect that may relieve symptoms quickly. However, menstrual syndrome may recur repeatedly, and patients’ expectations may be frustrated, so the number of clinical visits tended to decrease compared with the initial starting point. This may help to explain why the trends of TCM and WM utilization show an inverted pattern. If we ask why the return rate of TCM gynecology clinics is higher than that of WM, we may speculate that many Taiwanese women believe TCM is less stimulating to the body and has a maintenance effect.

In terms of personal characteristics, women of younger ages (15–39 years) and those who had higher economic status tended to use TCM clinics. These findings are not consistent with those of previous studies. One previous study suggested that medical care-seeking is not associated with age [20]. In addition, older people are more likely to use TCM as their main form of care. However, with the recognition of Chinese medicine by WHO, younger people began to pay attention to the benefits of TCM for improving overall health status and conditioning the body, and they became more likely to actively seek ways to improve their well-being by curing the root of the problem. Therefore, more and more young people currently choose TCM as their main medical care. Another possible explanation is that older women already have more experience dealing with the menstrual syndrome. Instead of using TCM, they might use other alternative therapy or food remedies to resolve these discomforts.

According to TCM, many ways of treatment are available to deal with symptoms, including medications, acupuncture, infrared rays, and so on. Although the NHI program covers TCM and makes these services affordable to all enrollees, many items are still not reimbursable by NHI. As a result, out-of-pocket items of complementary healthcare have become obstacles for low-income patients. The present study found that higher economic status was associated with TCM use, which is consistent with the findings of previous research [21].

Longitudinal data (60 months) from the present study revealed that women with medical history of infertility or who were ever hospitalized due to Ob/Gyn disorders would likely use more clinical outpatient services of both TCM and WM. Because both TCM and WM clinical outpatient services are covered by NHI, we reasonably suggested that these women increased outpatient follow-up once they had been diagnosed with the documented medical history. Previous study also has indicated that the extension of NHI benefits coverage led to an increase in the utilization of outpatient services across all income groups among patients [22].

On the other hand, the utilization of health preventive services, such as screening tests, had different effects on the use of TCM and WM outpatient services. Women receiving screening tests, such as cervical Pap smears and mammography, were less likely to use TCM outpatient services and were more likely to use WM outpatient services. Previous studies found that patients who underwent gynecological cancer screening were more likely to experience symptom discomfort and would, therefore, visit outpatient clinics for treatment [15]. In addition, the use of preventive healthcare is a specific category of WM. Therefore, women who performed these health prevention practices were basically more likely to agree with and, therefore, seek WM healthcare services.

The present study also found that women who have baby delivery history tended to reduce the use of outpatient services. After childbirth, the uterus and cervix are enlarged, and the uterus no longer contracts excessively. When menstruation returns, the menstrual blood is discharged smoothly, and the previous discomfort of menstrual syndromes may be relieved.

An important strength of this study is that it used data from a comprehensive, high quality national database, which minimized discrepancies and selection bias. In addition, the use of longitudinal data allowed us to conduct long-term research and made it possible to explore the changes in long-term trends.

Nevertheless, this study has several limitations. First, this study analyzed patterns in the outpatient utilization of presented gynecological diagnoses rather than TCM prescriptions. Therefore, treatment prescriptions of Chinese medicine were not analyzed, and it was not possible to distinguish the treatment options among patients and explore the side effects of TCM treatment. Second, although the NHIRD is a large and trusted source of patient data, all analyses were retrospective, which does not rule out selection bias nor allow inferences of cause. Third, the follow-up period of the database extends until 2013, making it more difficult to reflect current reality. Improving the study may involve beginning the next stage of clinical questionnaires to collect new cases for follow-up. Fourth, patients with medical and neurological causes of psychiatric symptoms were not excluded in this study. In addition, specific patient data were unknown, such as whether patients used Chinese herbal remedies obtained directly from TCM pharmacies with or without prescriptions from licensed TCM physicians. Fifth, the study also did not include medical visits that were not covered by the NHI program. Thus, the frequency of outpatient utilization may have been underestimated. Last, patients may have used both TCM and WM or used WM first and then changed to TCM, and such patterns could not be differentiated.

Only the medical records with the defined gynecological diagnosis were included in this study, leading to the loss of patients who recovered, died, or canceled the insurance. Because there is no death or surrender insurance information in the data, it is difficult to distinguish the number of cured patients vs. death or surrender insurance patients.