**2. Etiology**

Around 15% of couples have difficulty conceiving [15]. The etiology of infertility can be broadly classified into female‐ and male‐related factors. Among distinguishable female fac‐

tors, which are responsible for 81% of female infertility, the most common are ovulatory dis‐ orders (25%), endometriosis (15%), pelvic adhesions (12%), tubal blockage (11%), other tubal abnormalities (11%), and hyperprolactinemia (7%) [16]. Male factor infertility affects around 30–55% of all couples and is the most difficult form of infertility to treat [17]. The causes of male infertility include environmental disruptors, genetic defects, physiological and endo‐ crine failure, and testicular pathologies [18].

According to the theory of traditional Chinese medicine, syndromes of female infertility can be classified as the following: kidney deficiency, stagnation of liver qi, static blood blocking in uterine, and accumulation of phlegm‐wetness in the body. Constitution has a great effect on the syndrome patterns of many diseases including infertility. A report showed that the con‐ stitution ratio of yang deficiency, phlegm damp, and yin deficiency was 29.5, 20.0, and 21.0%, respectively, in sterility patients [19]. This report also pointed that kidney deficiency syndrome was positively correlated with yin deficiency and yang deficiency constitution, blood stasis syn‐ drome was positively associated with blood stasis and yang deficiency constitution, and liver stagnation syndrome was positively correlated with phlegm damp and damp heat constitution.

#### **2.1. Ovulatory disorders**

percentage of married women aged 15–44 years old who were infertile decreased from 8.5% in 1982 (2.4 million women) to 6.0% (1.5 million) in 2006–2010 [5]. In Taiwan, the total female fertility rate decreased from 7.04 million in 1951 to 1.175 million in 2015 [6]. Taiwan has thus become one of the countries with the lowest fertility rates in the world. In China, the 1‐ and 2‐year infertility rates in newly married couples were 12.5 and 6.6%, respectively [7]. In 2004, a WHO evaluation of Demographic and Health Surveys (DHS) data estimated that more than 186 million ever‐mar‐ ried women of reproductive age were infertile, translating into one in every four couples [8].

88 Chinese Medical Therapies for Diabetes, Infertility, Silicosis and the Theoretical Basis

A low fertility rate results in a low birth rate and an aging country. According to the Taiwan Population Policy White Paper, the total population of Taiwan is expected to decrease after 2022 [9]. A review showed that infertility or subfertility is associated with intimate partner violence (IPV) in low‐ and middle‐income countries (LMICs) [10]. Certain fertility treatments may increase the risk of ovarian or breast cancer [11, 12], while others have poor pharmaco‐ logical efficacy in infertile women older than 40 years [13]. Around one‐fifth of all subfertile couples seeking fertility treatment have clinically significant levels of depression, anxiety, and suffering, but the effects of educational and psychological interventions on mental health outcomes and pregnancy outcomes including distress, and live birth or ongoing pregnancy

**Figure 1.** Worldwide prevalence of primary female infertility (2010). Infertility prevalence is indexed based on the age of

the female partner; age‐standardized prevalence among women aged 20–44 years old is shown here [4].

Around 15% of couples have difficulty conceiving [15]. The etiology of infertility can be broadly classified into female‐ and male‐related factors. Among distinguishable female fac‐

rates, is unclear owing to the very low quality of evidence [14].

**1.3. Impact**

**2. Etiology**

A history of regular menses with molimina (breast tenderness, bloating, cramping, mood changes) is suggestive of ovulation in the majority (95%) of women [20]. Anovulation and oligo‐ovulation lead to infertility because an oocyte is not available every month for fertil‐ ization. A woman's fecundability reaches a peak in her late‐twenties and decreases with advancing age, with a more rapid decline after her mid‐thirties [21]. Ovarian ageing causes a progressive loss of the finite pool of primordial follicles and a decrease in the quality of oocytes, mainly because of the accumulation of chromosomal abnormalities [22]. Polycystic ovarian syndrome (PCOS) is a common ovulatory disorder, and patients with this diagnosis are often obese and oligomenorrheic. They tend to have difficulty conceiving owing to ovula‐ tory dysfunction as well as poor oocyte quality and endometrial receptivity [23]. However, the results of epidemiologic data obtained mainly from comparative studies and cohorts, have concluded that the role and size (<6 cm) of ovary cysts in infertility is controversial [24].

#### **2.2. Endometriosis**

The rate of infertility among women with endometriosis ranges from 30 to 50%, and dys‐ function is due to various mechanisms including pelvic adhesions, abnormal tubal transport, implantation defects, and intraperitoneal inflammation, which can decrease oocyte quality or oocyte‐sperm interactions [25].

#### **2.3. Pelvic adhesions**

Most adhesions occur after surgical procedures, but can also occur following infection, isch‐ emia, endometriosis, or reaction to a foreign body, and these cause infertility by distort‐ ing pelvic anatomy and by blocking the fallopian tubes [26]. Peritubal adhesions negatively affect ovum transportation, while periovarian adhesions inhibit ovum release and ovulatory function [27, 28].

#### **2.4. Tubal blockage and other tubal abnormalities**

Tubal anomalies that contribute to infertility include congenital absence and major diver‐ ticula, duplication of the tubes, tubal occlusion, and hydrosalpinx [29, 30]. Other causes of tubal infertility include endometriosis, intrauterine contraceptive devices, infections (gonor‐ rhea, chlamydia trachomatis, and genital tuberculosis), and postoperative complications of abdominal surgery [31].

#### **2.5. Hyperprolactinemia**

Symptoms of hyperprolactinemia include amenorrhea, oligomenorrhea, infertility, decreased sexual desire, and habitual abortion. Women may also have signs of chronic hyperandrogen‐ ism such as acne and hirsutism, which may be related to increasing dehydroepiandrosterone sulfate (DHEAS) secretion from the adrenal glands [32].
