Clinical efficacy of Wenjing decoction in the treatment of ovulatory disorder infertility: A systematic review and meta-analysis.

Infertility is a disease of both male and female reproductive system that has attracted much attention all over the world and about 12% to 15% of couples of childbearing age in the world are suffering from infertility. [ 1 ] In China, the incidence rate of infertility is 7% to 10%, while 12.7% in America. [ 2 ] The main causes of female infertility are ovulation disorder, endometriosis, pelvic adhesion, tubal obstruction and other tubal abnormalities, as well as congenital (mediastinal uterus) and acquired (myoma and adhesion) uterine abnormalities. [ 3 , 4 ] The infertility related to ovulation disorder accounts for about 25% to 30% of the infertile population. [ 2 ] Epidemiological survey results demonstrated that ovulatory disorder infertility (ODI) showed a significant upward trend in the incidence rate of infertility. [ 5 ] That means mankind is facing a more and more serious crisis of fertility. Therefore, solving this problem is an important topic of reproductive medicine. At present, western drugs including clomiphene, letrozole, oral contraceptive (OC), human menopausal gonadotropin (HMG), human chorionic gonadotropin (HCG) are used for patients with ODI by inducing ovulation. [ 6 ] However, there are a series of adverse reactions during the treatment, such as insomnia, nausea and vomiting, headache, hot flashes, low pregnancy rate, high abortion rate, and so on. [ 7 ] About one-fourth of polycystic ovary syndrome (PCOS) women do not ovulate following the maximum dose of clomiphene and among those women, who ovulate, only about 16% to 28% women achieve a live birth. [ 8 ] Although assisted reproductive technology brings good news to patients with ODI, it cannot be widely used for patients because of its high cost, low success rate per cycle, obvious side effects, and many social problems. Therefore, it is necessary to develop new drugs, which will be more safe and effective. In recent years, traditional Chinese medicine (TCM) that includes but not limited to Chinese herbal medicine has attracted more and more attention. [ 9 ] According to the theory of TCM, the balance of Qi, blood, Yin and Yang is very important to health of people, while TCM could treat diseases by regulating Qi, blood, Yin and Yang. [ 10 – 17 ] WJD, a classic prescription for disease of TCM Gynecology, includes Wuzhuyu ( Tetradium ruticarpum ), Danggui ( Angelica sinensis ), Chuanxiong ( Ligusticum chuanxiong ), Guizhi ( Ramulus Cinnamomi ), Shengjiang ( Rhizoma zingiberis recens ), Banxia ( Pinellia ternat a), Gancao ( Glycyrrhiza uralensis ), Ejiao ( Asini Corii Colla ), Mudanpi ( Cortex Moutan ), Chishao ( Radix Paeoniae Rubra ), Renshen ( Panax L ), and Maidong ( Ophiopogon japonicus ). According to the theory of TCM, Yang deficiency and blood stasis are the basic pathogenesis of ODI. Among the Chinese medicines of WJD, Wuzhuyu, Guizhi, and Renshen could warm and tonify Yang Qi; Danggui, Chuanxiong, Ejiao, Mudanpi, and Chishao could nourish blood and invigorate the circulation of blood; Shengjiang, Banxia, Gancao, and Maidong could improve digestive function. Therefore, WJD was widely used in the treatment of ODI. Nevertheless, the efficacy of WJD for ODI has not been clarified by meta-analysis. In this study, we searched the relevant literature in the electronic database and compared the efficacy of WJD and clomiphene by meta-analysis.

Q.Q.Z. and H.L.D. contributed to the conception and design of the study. Q.Q.Z. performed the statistical analysis and drafted the manuscript. Q.Q.Z., Z.F.Y., and M.R.L. contributed to the literature search and study selection. Q.Q.Z., Z.F.Y. contributed to the data extraction. Q.Q.Z. contributed to the revisions of the manuscript. All authors read and approved the final manuscript. Conceptualization: Q.Q.Z. and H.L.D. Data curation: Q.Q.Z., Z.F.Y., M.R.L. Investigation: Q.Q.Z. Resources: Q.Q.Z., Z.F.Y., M.R.L. Software: Z.F.Y., M.R.L. Writing–original draft: Q.Q.Z. Writing–review and editing: Q.Q.Z. and H.L.D.

This study was registered on PROSPERO (No. CRD42021266963). Four Chinese databases and 4 English databases, including the Cochrane Library, PubMed, Embase, Web of Science, China National Knowledge Infrastructure, WanFang Data, VIP Database, and China Biology Medicine were searched for the literature which were published from the inception of each database to July 1, 2021. The following search terms were used: “infertility”[MeSH Terms] OR “infertile” [Title/Abstract] OR “steril” [Title/Abstract] OR “sterility” [Title/Abstract] AND “anovulation” [MeSH Terms] OR “anovulatory” [Title/Abstract] OR “ovulatory dysfunction” [Title/Abstract] OR “ovulatory disorders” [Title/Abstract] OR “ovulation failure” [Title/Abstract] OR “ovarian stimulation” [Title/Abstract] OR “ovarian induction” [Title/Abstract]) AND (“Wenjing decoction” [Title/Abstract] OR “Wenjing formula” [Title/Abstract] OR “Wenjing tang” [Title/Abstract])OR “WJD” [Title/Abstract]) AND “clomiphene” [MeSH Terms]. All included researches were in English or Chinese. The following conditions were required: All patients were diagnosed with ODI. The diagnostic criteria were in accordance with Rotterdam standard (2003) developed by the European Society for Human Reproduction and embryo and American Society of Reproductive Medicine (ESHRE/ASRM) [ 18 ] and the Infertility, published by the Chinese people’s Health Publishing House in 1998 [ 19 ] ; All studies included should be RCTs. Intervention methods include WJD and WJD combined with clomiphene while control method should be clomiphene; Outcomes include clinical efficacy rate, ovulation rate, pregnancy rate, dominant follicle diameter, endometrial thickness, estradiol (E 2 ), follicle-stimulating hormone (FSH), and luteinizing hormone (LH). Non-randomized controlled trial (RCT) such as experimental research or review; Interventions include other TCM treatments such as acupuncture and cupping; Researches with a sample size which is <20 and repeated reports; The full text of the research was not available. Two researchers (Q.Q.Z. and Z.F.Y.) evaluated the included RCTs and collected data separately. All differences were resolved by the third author (H.L.D.). Finally, the data were imported into excel. All data as follows were collected: the last name of the first author; the year of publication; the number of patients; the infertility types of patients; age; intervention and comparison; outcomes including clinical efficacy rate, ovulation rate, pregnancy rate, dominant follicle diameter, endometrial thickness, and E 2 , FSH, LH. The risk of bias (ROB) within studies were assessed by the Cochrane ROB assessment tool. Seven parts were included for evaluation: Random sequence generation (selection bias); Allocation concealment (selection bias); Blinding of participants and personnel (performance bias); Blinding of the outcome assessment (detection bias); Incomplete outcome data (attrition bias); Selective reporting (reporting bias); Other sources of bias. Review Manager 5.3 were used for statistical analysis. Odds ratio (OR) with 95% confidence interval (CI) were used as the effect for dichotomous variable while mean difference (MD) for continuous variable. P   .1, I 2  < 50%), the fixed-effect model was used. Otherwise, the random effect model would be selected. Before that, subgroup analysis or sensitivity analysis can be carried out.

A total of 392 potentially eligible articles were obtained, and 201 duplicate articles were deleted. Of the remaining 191 studies evaluated in detail, 148 were excluded for one or more of the following reasons. The study was case report or clinical experience; the study included other therapies (such as massage, acupuncture, and other TCM prescriptions); and the study was unrelated to ODI. Further excluded another 32 studies for the following reasons: the study was non-RCT; drugs in the study did not include WJD or clomiphene; outcomes in the study did not include clinical efficacy rate, ovulation rate, pregnancy rate, dominant follicle diameter, endometrial thickness, E 2 , FSH, and LH. Finally, 11 studies [ 10 – 17 , 20 – 22 ] were identified. The research selection process and reasons for excluding articles were shown in Figure 1 . PRISMA flowchart detailing the data identification, screening, eligibility, and inclusion. FSH = follicle stimulating hormone, LH = luteinizing hormone, NR= not reported, ODI = ovulation disorder infertility, RCT = randomized controlled trial, WJD = Wenjing decoction. Among the 11 studies a total of 915 patients were included, containing 476 in the intervention group and 439 in the control group. Six of the 11 studies (493 participants) compared WJD with clomiphene, while the other 5 studies (422 participants) compared the effects of WJD combined with clomiphene and clomiphene alone. There were 8 studies reported the clinical effective rate, 5 studies reported the pregnancy rate, 3 studies reported the ovulation rate, 3 studies reported dominant follicle diameter, 4 studies reported endometrial thickness, 3 studies reported the level of E 2 , 4 studies reported the level of FSH, and 4 studies reported the level of LH, respectively. Detailed characteristics of studies were shown in Table 1 . Characteristics of the 11 included RCTs. C = control group, E 2 = estradiol, FSH = follicle stimulating hormone, LH = luteinizing hormone, NR= not reported, RCT = randomized controlled trial, T = treatment group, WJD = Wenjing decoction. ① clinical efficacy rate, ② pregnancy rate, ③ ovulation rate, ④ dominant follicle diameter, ⑤ endometrial thickness, ⑥ E2, ⑦ FSH, ⑧ LH. The Cochrane Collaboration assessment tool was applied to evaluate the ROB of the included studies. Among the 11 studies, 4 of them which mentioned the specific random allocation method were considered as “low-risk,” while 7 which mentioned only random sequences were considered as “unclear.” None of 11 RCTs mentioned allocation concealment, blinding of subjects and researchers or blinding of the evaluators to the outcome, so they were all evaluated as “unclear” in the 3 parts. All of the RCTs reported complete outcome data and all of them were regarded as “low ROB” in terms of the integrity of the final data. About the rest 2 parts, selective reporting results and other bias, detailed information cannot be obtained, thus we evaluated all of them as “unclear.” The specific results of ROB assessment for all RCTs were shown in Figure 2 . Assessment of risk of bias. Eight of the 11 studies included reported clinical effective rate in patients with ODI. Among them, 5 studies included 356 patients (178 in intervention group, 178 in control group) compared the clinical efficacy rate of patients who received WJD with that of patients who received clomiphene. Fixed-effect model was chosen due to heterogeneity test result (I 2 = 0%, P = .99). Meta-analysis result showed that WJD was better than clomiphene for patients with ODI in terms of clinical effective rate (OR = 1.22, 95% CI: 1.12–1.33, P < .00001) (Fig. 3 A). Three studies included 356 patients (178 in the intervention group, 178 in the control group) compared the clinical efficacy rate of patients who received WJD plus clomiphene with that of patients who received clomiphene. Fixed-effect model was chosen due to heterogeneity test result (I 2  = 0%, P = .81). Meta-analysis result showed that WJD combined with clomiphene was better than clomiphene alone for patients with ODI in terms of clinical effective rate (OR = 1.20, 95% CI: 1.08–1.34, P = .001) (Fig. 3 B). Meta-analysis of the clinical efficacy rate. (A) WJD vs clomiphene; (B) WJD + clomiphene vs clomiphene. WJD = Wenjing decoction. Five of the 11 studies included reported pregnancy rate in patients with ODI. Among them, 2 studies included 197 patients (117 in intervention group, 80 in control group) compared the pregnancy rate of patients who received WJD with that of patients who received clomiphene. The fixed-effect model was chosen due to heterogeneity test result (I 2 = 0%, P = .90). Meta-analysis result showed that WJD was better than clomiphene for patients with ODI in terms of pregnancy rate (OR = 1.54, 95% CI: 1.15–2.07, P = .004) (Fig. 4 A). The other 3 studies, including 304 patients (152 in intervention group, 152 in control group), compared the pregnancy rate of patients who received WJD plus clomiphene with that of patients who received clomiphene. Fixed-effect model was chosen due to heterogeneity test result (I 2  = 34%, P = .22). Meta-analysis results showed that WJD combined with clomiphene was better than clomiphene alone for patients with ODI in terms of pregnancy rate (OR = 1.79, 95% CI: 1.37–2.35, P < .0001) (Fig. 4 B). Meta-analysis of the pregnancy rate. (A) WJD vs clomiphene; (B) WJD + clomiphene vs clomiphene. WJD = Wenjing decoction. Two of the 11 studies, which included 197 patients (117 in intervention group, 80 in control group) and involved comparison between WJD and clomiphene, reported ovulation rate in patients with ODI. The fixed-effect model was chosen due to heterogeneity test result (I 2  = 0%, P = 0.98). Meta-analysis results showed that WJD was better than clomiphene for patients with ODI in terms of ovulation rate (OR = 1.34, 95% CI: 1.07–1.67, P = .01) (Fig. 5 ). Meta-analysis of the ovulation rate (WJD vs clomiphene). WJD = Wenjing decoction. Three of the 11 studies, which included 224 patients (112 in intervention group, 112 in control group) and involved comparison between WJD and clomiphene, reported Dominant follicle diameter in patients with ODI. The result showed significant heterogeneity was existed (I 2  = 89%, P < .0001). Sensitivity analysis showed that the results were robust. The random effect model was chosen. The meta-analysis result showed that WJD was better than clomiphene for patients with ODI in terms of dominant follicle diameter (MD = 1.85, 95% CI: 0.68–3.02, P = .02) (Fig. 6 ). Meta-analysis of the dominant follicle diameter (WJD vs clomiphene). WJD = Wenjing decoction. Three of the 11 studies, which included 224 patients (112 in intervention group, 112 in control group) and involved comparison between WJD and clomiphene, reported Endometrial thickness in patients with ODI. The result showed significant heterogeneity was existed (I 2  = 76%, P = .01). Sensitivity analysis showed that the results were robust. The random effect model was chosen. Meta-analysis results showed that WJD was better than clomiphene for patients with ODI in terms of endometrial thickness (MD = 1.50, 95% CI: 0.90–2.10, P < .00001) (Fig. 7 ). Meta-analysis of the endometrial thickness (WJD vs clomiphene). WJD = Wenjing decoction. Three of the 11 studies, which included 188 patients (94 in intervention group, 94 in control group) and involved comparison between WJD and clomiphene, reported E 2 level in patients with ODI. Fixed-effect model was chosen due to heterogeneity test result (I 2 = 0%, P = .99). Meta-analysis results showed that the E 2 level in patients who received WJD was significantly higher than those who received clomiphene (MD = 91.0, 95% CI: 80.3–101.88, P < .00001) (Fig. 8 A). Meta-analysis on the level of sex hormone (WJD vs clomiphene). (A) E2; (B) FSH; (C) LH. FSH = follicle stimulating hormone, LH = luteinizing hormone, WJD = Wenjing decoction. Four of the 11 studies, which included 272 patients (136 in intervention group, 136 in control group) and involved comparison between WJD and clomiphene, reported the FSH level in patients with ODI. The result showed significant heterogeneity was existed (I 2  = 81%, P = .001) (see Fig. S1, Supplemental Digital Content, http://links.lww.com/MD/G894 , which illustrates meta-analysis on the level of FSH before Mao 2011 was deleted). Sensitivity analysis showed that the result of Mao 2011 contributed a lot to heterogeneity. Thus, we deleted this article and chose fixed-effect model due to heterogeneity test result (I 2  = 0%, P = .61). Meta-analysis result showed that the FSH level in patients taking WJD was significantly lower than those taking clomiphene (MD = −0.93, 95% CI: −1.13 to −0.72, P < .00001) (Fig. 8 B). Four of the 11 studies, which included 272 patients (136 in intervention group, 136 in control group) and involved comparison between WJD and clomiphene, reported the LH level in patients with ODI. The result showed significant heterogeneity was existed (I 2  = 75%, P = .007) (see Fig. S2, Supplemental Digital Content, http://links.lww.com/MD/G894 , which illustrates meta-analysis on the level of LH before Hu 2021 was deleted). Sensitivity analysis showed that the result of Hu 2021 contributed a lot to heterogeneity. Thus, we deleted this article and chose the fixed-effect model due to heterogeneity test result (I 2  = 41%, P = .19). Meta-analysis result showed that the LH level in patients who received WJD was significantly lower than those who received clomiphene (OR = −4.41, 95% CI: −4.80 to −4.03, P < .00001) (Fig. 8 C).

Ovulation disorder is one of the main causes of female infertility, accounting for 25% to 35% of female infertility. [ 23 , 24 ] At present, ovulation disorder is widely considered to be related to mental stress, eating habits, and living environment. Western medicine including clomiphene and other drugs, which promote ovulation, treat the disease mainly by increasing FSH and LH to promote the normal growth and smooth excretion of follicles. However, they have some adverse effects, such as gastrointestinal reactions, headache, hot flashes, high ovulation rate, and low pregnancy rate. TCM, as an important role of the complementary and alternative medical treatments, has obvious advantages in the treatment of the disease. [ 25 , 26 ] WJD is a TCM prescription of which the main therapeutic principle tonifies Yang Qi and invigorates the circulation of blood. It is widely used to treat this disease in China. In this study, we searched the electronic database for literature and evaluated the efficacy of WJD in the treatment of ODI by the method of meta-analysis. Eleven RCTs including 915 patients with ovulatory infertility were collected and analyzed. The outcome indicators involved clinical effective rate, ovulation rate, pregnancy rate, sex hormone level, endometrial thickness, and dominant follicle diameter. In results of meta-analysis, WJD was better than clomiphene in terms of clinical effective rate (OR = 1.22, 95% CI: 1.12–1.33, P < .00001), ovulation rate (OR = 1.34, 95% CI: 1.07–1.67, P = .01), pregnancy rate (OR = 1.54, 95% CI: 1.15–2.07, P = .004), endometrial thickness (MD = 1.50, 95% CI: 0.90–2.10, P < .00001), dominant follicle diameter (MD = 1.85, 95% CI: 0.68–3.02, P = .02). It was also showed that WJD combined with clomiphene was better than clomiphene in terms of clinical effective rate (OR = 1.20, 95% CI: 1.08–1.34, P = .001), pregnancy rate (OR = 1.79, 95% CI: 1.37–2.35, P < .0001). That means TCM-related treatments have obvious advantages in improving clinical effective rate, ovulation rate, pregnancy rate, dominant follicle diameter, and endometrial thickness. At present, the molecular mechanism of the occurrence and development of infertility is not clear. It is widely believed that steroid hormone disorder and hypothalamic pituitary dysfunction can lead to oocyte and granulosa cell apoptosis. [ 27 – 30 ] Therefore, regulating hormone level, restoring hypothalamic pituitary function, inhibiting oocyte and granulosa cell apoptosis and maintaining cell growth are potential strategies to promote the formation of dominant follicles or mature follicles. We reviewed the included literature and found that the population in studies which reported E 2 , FSH, or LH included in our literature belonged to WHO II ODI. This type of ODI mostly shows high levels of LH and relatively normal levels of E 2 and FSH. Our results showed that E 2 (MD = 91.0, 95% CI: 80.3–101.88, P < .00001) level in patients who received WJD was significantly higher than those who received clomiphene while FSH (MD = −0.93, 95% CI: −1.13 to −0.72, P < .00001) and LH (MD = −4.41, 95% CI: −4.80 to −4.03, P < .00001) levels in patients who received WJD were significantly lower than those who received clomiphene. Because other results have shown that WJD had advantages in the treatment of ODI, the differences between WJD and clomiphene in regulating hormones may be the important reasons for the better curative effect of WJD. However, due to the lack of relevant basic research, we still do not know the specific mechanism of WJD in the treatment of ODI. Clinically, the main treatment methods are symptomatic treatments based on the causes of anovulation, such as clomiphene citrate, clomiphene plus hormone, gonadotropins (Gn), gonadotropin-releasing hormone (GnRH), bromocriptine, and glucocorticoid. However, long-term application of these drugs may induce adverse reactions, such as reproductive system tumors, ovarian hyperstimulation syndrome, and so on. As a traditional medical treatment which shows its advantages through multilevel and multitarget methods, TCM has been used to treat diseases under the guidance of TCM theory for thousands of years in China. [ 31 ] WJD, as one of famous traditional Chinese decoction, has been widely used in the treatment of infertility. The experimental study showed that [ 32 ] the mechanism of WJD in improving the E 2 level of rat ovarian cells may be related to its improvement of antioxidant damage. Oxidative stress plays an important role in cell apoptosis which is widely considered as a key mechanism of ODI. Therefore, WJD might improve ODI through the antioxidant effect. In addition, experimental studies suggest that related components play a unique role in inhibiting oxidative stress. 20 ( R ) - Ginsenoside Rg3, one of the ingredients of Renshen, has been proved to have obvious antioxidant effect, and may improve cell apoptosis by regulating PI3K/Akt signaling pathway. [ 33 ] Khan et al [ 34 ] demonstrated that glycyrrhizic acid, as one of the components of Gancao, had obvious antiinflammatory and antiapoptotic effects. Experimental study of Mahmoud et al dispalyed that ferulic acid, a component of Danggui could reduce oxidative stress, inflammation and cell death by activating Nrf2/HO-1 signal and PPARγ. [ 35 ] Senkyunolide H, as one of the components of Chuanxiong, has been prevented oxidative stress by reducing ROS and increasing activity of superoxide dismutase (SOD), catalase, and glutathione peroxidase. [ 36 ] Mo et al [ 37 ] showed that extract of the herb Chishao could improve oxidative stress and cell apoptosis. Paeonol, which is extracted from Cortex Moutan, has been proved that it could inhabit oxidative stress induced by H 2 O 2 via activating Nrf2/Keap1 pathway. [ 38 ] Rutaecarpine (Rut), a quinazolinocarboline alkaloid extracted from Wuzhuyu was shown that it could ameliorate oxidative stress by improving SOD and glutathione (GSH), while inhibiting malondialdehyde (MDA). [ 39 ] Niu et al [ 40 ] showed that Chinese herbs Guizhi could improve oxidative stress induced by Chinese herbs Mahuang ( Ephedra sinica Stapf ). The steroidal saponins extract from Maidong and ingredients of Shengjiang have been proved to have antiinflammatory and antioxidant effects. [ 41 , 42 ] Tang et al [ 43 ] proved that ethanol extract of Banxia could slows down cell senescence induced by oxidative stress. The experiment of Li et al described that Ejiao digested by gastrointestinal enzymes could prevent cell death induced by H 2 O 2 . [ 44 ] Therefore, inhibiting oxidative stress may be the potential mechanism of WJD to improve ODI. However, because the specific mechanism is still unclear, further researches related to molecular mechanism are necessary. Previous meta-analysis explored the efficacy of TCM in the treatment of infertility, but the intervention or control measures were not specified. [ 45 ] Our study evaluated the effect of WJD in the treatment of anovulatory infertility. We not only limited the prescription of TCM, but also limited the control treatment. However, the current research still has some limitations. First, the subjects are all from China, which limits the diversity of sample, meaning that our conclusions may not apply to the population in other regions. Second, for most of the included studies, the methods of randomization, allocation concealment and blinding were not clearly reported, and that may cause bias. Besides, due to different measurement methods and operator subjectivity, there may be errors in the measurement of endometrial thickness and dominant follicle diameter. Thus, much more reasonable and scientific RCT with large sample size remains to carry out to further verify our conclusion in the future.

WJD may be effective in the treatment of patients with ODI. Due to the quality and quantity of literature, RCT with large sample size and high quality need to be performed to verify our conclusion.

We thank the authors of the included studies for their help.