Globally, there is an increasing number of studies on women’s lifelong use of herbal medicines (HM). Several studies have documented women’s HM use in various life stages, starting from menstruation, pregnancy, childbirth, postpartum, and menopause (Ngoma and Siachapa, 2017; Wang J. et al., 2018; Moini Jazani et al., 2018; Zheng et al., 2019; Adane et al., 2020; Sumankuuro et al., 2020). Especially during some of these life stages, such as pregnancy, delivery, and the postpartum period, women’s HM use should be paid close attention to, as seemingly naive HM that has no negative impact on non-pregnant women can have a detrimental effect on the child and pregnant woman (Budzynska et al., 2012; Ahmed et al., 2017).

According to the World Health Organization, exclusive breastfeeding (EBF) is an essential practice during the postpartum period for maternal and child health (WHO, 2015), as it is one of the most effective ways to promote both mothers’ and newborns’ physiological and psychological health (Ebina and Kashiwakura, 2012; Antonakou et al., 2013; Al Sabati and Mousa, 2019; Mikšić et al., 2020). Breastmilk is more natural and cost-effective than bottle feeding and ensures ideal nutrition for newborns, thus promoting infant health, providing essential bioactive nutrients, and lowering the risks for various infections and hospitalizations (Oguchi et al., 1997; Butte et al., 2002; Hauck et al., 2011; Ajetunmobi et al., 2015). In addition, breastfeeding facilitates mother and child bonding by promoting physical intimacy between the mother and child (Johnson, 2013; Liu et al., 2013). However, up to 92% of nursing women encounter various difficulties during their breastfeeding journeys (Wagner et al., 2013). Some mothers seek an alternative mode of care, such as HM, to alleviate the problems due to the lack of access to conventional healthcare services and the belief that HM is more natural and safe to use than conventional medicine (Augustino and Gillah, 2005; Sim et al., 2013; Aleandri et al., 2014; Zheng et al., 2020). Some of the commonly used HM among breastfeeding mothers include fenugreek (Trigonella foenum-graecum L.), ginger (Zingiber officinale Roscoe), fennel (Foeniculum vulgare Mill.), shatavari (Asparagus racemosus Willd.), and aniseed (Pimpinella anisum L.). Moreover, various phytochemical compounds (e.g., glycosides, alkaloids, flavonoids, and minerals) found in medicinal plants modulate hormone levels and act as lactogenic agents (Bnouham, 2010; Dandotiya et al., 2013; Sim et al., 2013).

Nevertheless, there is much debate about whether the existing evidence related to breastfeeding mother’s HM use supports their safety and efficacy (Sim et al., 2013; Bettiol et al., 2018a) as previous studies show inconclusive evidence explaining the mechanism behind herbs as galactagogues, requiring further research to determine HM’s clinical efficacy (Anderson, 2017; Bowman, 2017; Wang S. et al., 2018; Sibeko et al., 2021). Furthermore, inappropriate use of certain HM during breastfeeding was found to cause allergic reactions and neurotoxic effects on newborns (Bnouham, 2010). Yet, irrespective of the lack of scientific evidence and potential harm to newborns, as large as 97% of breastfeeding women use HM to overcome challenges with breastfeeding, and concerns are rising about the level of knowledge among healthcare providers on breastfeeding women’s HM use (Sim et al., 2013; Bettiol et al., 2018b; James et al., 2019; Zheng et al., 2020).

Thus, several studies have examined breastfeeding mothers’ HM use in various cultural settings (Bnouham, 2010; Sim et al., 2013; Aleandri et al., 2014; Bettiol et al., 2018b; James et al., 2019; Orabi et al., 2020; Zheng et al., 2020). However, limited data is available regarding the HM use in East African countries like Tanzania even though HM use is widely practiced to treat various physical conditions such as women’s complications as well as infectious and chronic diseases (Augustino and Gillah, 2005; Moshi et al., 2009; Amri and Kisangau, 2012; Kacholi and Amir, 2022). Consequently, breastfeeding mothers’ self-care practices must be examined to establish appropriate policy measures and clinical protocols to ensure the health of the mother and the child. Therefore, this study aims to examine the pattern and factors associated with HM use among breastfeeding mothers in Tanzania. Furthermore, this study emphasizes the importance of informing policymakers for developing a clinical guideline that could improve the self-care behaviors of women during breastfeeding.

This study explored the prevalence and determinants of HM use among breastfeeding mothers in Tanzania, and our results revealed the high popularity of HM use among nursing mothers. As previous studies found, globally, 37.0–97.3% of mothers use HM to ease breastfeeding problems (Sim et al., 2013; Aleandri et al., 2014; Bettiol et al., 2018b; James et al., 2019; Zheng et al., 2020). Such variations in utilization rate can be attributed to differences in how HM is defined in each study, as well as the differences in the public acceptance and availability of HM due to cultural influences (Sim et al., 2013; James et al., 2019). Considering the low prevalence of exclusive breastfeeding and lack of appropriate breastfeeding knowledge among Tanzanian women (Hashim et al., 2016; Hasselberg et al., 2016; Kaaya et al., 2021) due to various individual, socio-cultural, and environmental barriers (Agho et al., 2019; Mundagowa et al., 2021), appropriate use of HM as galactagogues can potentially allow the mothers to engage in optimal breastfeeding practices and act as a safe alternative to synthetic galactagogues (Penagos-Tabares et al., 2014; Jyotsna and Sameet, 2020).

Similar to the broad range observed in the prevalence of HM use, wide varieties of HM were used by breastfeeding mothers in different countries. In Tanzania, the most commonly used herbal products were P. nigrum and C. pepo, whereas in Sierra Leone, Cassia sieberiana DC. and Luffa acutangula (L.) Roxb. were the most popular (James et al., 2019). T. foenum-graecum and Z. officinale use was the highest during lactation in Australia (Sim et al., 2013), while Tetrapanax papyrifer (Hook) K. Koch and Vaccaria segetalis (Neck.) Garcke consumption were most prevalent in Macau (Zheng et al., 2020). Such differences in preferred modalities can be due to different cultural traditions, as each traditional medicine is rooted in varying climate settings and religious backgrounds (Jaiswal and Williams, 2017; Tesfahuneygn and Gebreegziabher, 2019; Zhang and Dong, 2020). In addition, differences in the main indications for use reported among the studies may explain variations in HM modalities observed. For example, in our study, the most reported indication for HM was poor milk production, yet, in the Italian study, the main indications for HM use were dermatological conditions such as preventing stretch marks and preparing nipples for breastfeeding (Aleandri et al., 2014). Furthermore, among the Macau women, the primary indications for use were in relation to modulating the amount of breastmilk produced and managing breast and nipple pain (Zheng et al., 2020). These findings indicate that variations in the types of HM used can be expected depending on women’s cultural background and main indications for use (Forinash et al., 2012; Budzynska et al., 2013).

The procedures for preparing herbal remedies also vary by cultural background. P. nigrum, used by 80% of mothers in this study, is considered a medicinal plant in various cultures (Jamal et al., 2011; Takooree et al., 2019) and is specifically used to promote breastmilk production and postpartum care in India, Indonesia, and Morocco (Ramarao et al., 2000; Buragohain, 2008; Bnouham, 2010; Dandotiya et al., 2013; Chellappandian et al., 2014; Goyal, 2017; Muslichah et al., 2021). Depending on the cultural tradition, P. nigrum’s fruits are often mixed with other herbs (i.e., Terminalia chebula Retz., Piper longum L., Zingiber officinale Rosc., Curcuma aeruginosa Roxb., and Piper betel L.) and prepared as herbal concoctions to be consumed as galactagogue (Jyotsna and Sameet, 2020; Muslichah et al., 2021). Although not native to Africa, P. nigrum is also cultivated in East, Central, and West African regions and is often used as food condiments, insecticides, and cold-remedy (Kuete, 2017). It is also considered a galactagogue in places, and lactating mothers are recommended to consume a porridge with P. nigrum to promote breastmilk production (Hasselberg et al., 2016; Makwetta, 2021).

Nevertheless, despite women’s high dependency on HM to improve their breastfeeding due to the perception that HM is a natural and safe alternative to conventional medicine, HM’s clinical efficacy and safety as galactagogues still remain inconclusive and need further research (Sim et al., 2013; Zheng et al., 2020). For example, in the case of P. nigrum, its reputation as a lactogenic agent have received limited attention and relies on anecdotal evidence rather than clinical (Khare, 2007; Takooree et al., 2019). This may be because modalities such as P. nigrum are considered a food additive rather than a product with pharmacological value in many cultures, the importance of examining the effectiveness and potential dangers of such modalities can be neglected (Heinrich, 2016).

Although P. nigrum is better recognized for its anti-bacterial and anti-inflammatory effects in the existing literature, previous findings suggest its potential indirect effect as a galactagogue (Takooree et al., 2019). For instance, piperine, the active alkaloid contained in P. nigrum, improves the digestive capacity and enhances the bioavailability of drugs by increasing absorption activity in the intestines (Srinivasan, 2007; Goyal, 2017; Haq, et al., 2021) Piperine also possesses antioxidant properties which offer protection against oxidative stress by removing free radicals, reactive oxygen species, and chemical carcinogens (Srinivasan, 2007; Haq, et al., 2021). Managing postpartum oxidative stress is important as prolonged stress is involved in the pathogenesis of various maternal and neonatal diseases and can potentially alter the quality of breastmilk (Ozsurekci & Aykac, 2016; Kuramoto & Kitagawa, 2017). As consumption of balanced meals and proper nutrition is crucial for successful postpartum recovery and breastfeeding, piperine’s positive effect on the digestive tract, as well as the antioxidative effect may have helped the mothers to maintain good health and nutritional status to sustain optimal breastfeeding (Mistry & Williams, 2011; Goyal, 2017; Haq, et al., 2021). Nevertheless, as lactating mothers’ consumption of P. nigrum results in the transfer of piperine into the breastmilk, its potential effect on newborns warrants further investigation (N' Diaye et al., 2021).

Consumption of C. pepo was also prevalent among Tanzanian mothers. An animal study found that phytochemicals of C. pepo extract have a stimulatory effect on the pituitary gland, which stimulates prolactin secretion and increases the production of breast milk (Malgwi et al., 2013). However, further pharmacological research is required to ascertain their clinical efficacy in humans. As such, large-scale human clinical trials should be conducted for various traditional modalities to generate scientific evidence and demonstrate the safety and effectiveness of HM used among breastfeeding mothers (Jyotsna and Sameet, 2020).

In addition to the lack of scientific evidence to support HM’s effectiveness as galactagogues, the potential toxicity of HM due to heavy metal contamination is also a significant problem (Okem et al., 2014; Zhou et al., 2019; Luo et al., 2020). Because heavy metal components can pass through the breastmilk, inappropriate use of HM can expose infants to toxic substances (Palmieri et al., 2019). In fact, a study from Taiwan found that mothers’ consumption of Chinese herbal medicine was associated with the lead body burden in infants, posing potential health risks (Chien et al., 2006). The problems with contaminated HM have received considerable attention among academics and policymakers as HM is often obtained from unreliable sources such as local herbal shops and supermarkets; therefore, it is difficult to determine whether herbal products are manufactured and processed safely (Kunle et al., 2012; Sim et al., 2013; Aleandri et al., 2014). Thus, regulatory measures should be established to properly monitor the production of herbal products.

Lack of communication on HM use between the healthcare providers and nursing mothers is also a growing issue as poor communication can inhibit proper physician intervention when potential harm arises from inappropriate HM use (Foley et al., 2019). Congruent with previous findings, more than half of breastfeeding mothers in this study did not disclose their HM use to the doctors because the doctors did not ask and the women feared the doctors’ negative response (Foley et al., 2019; James et al., 2019). This implies that to prevent the potential risk of HM associated with inadequate patient-doctor communication, the physicians should actively inquire the nursing mothers about HM use and provide appropriate feedback to protect the health of the mothers and children.

Lastly, potential predictors of HM use identified in our sample include having low breastmilk supply and higher education attainment. Higher education level was frequently associated with the use of the non-conventional mode of care as people with higher education levels tend to have better health literacy, thus are more likely to practice patient autonomy and actively seek additional modes of care (Kemppainen et al., 2018; Fjær et al., 2020). Additionally, previous studies also found the age of the breastfeeding child, family income, ethnicity, previous use and positive attitudes towards non-conventional therapies, and the perceived accessibility of reliable information on HM use to be associated with HM use (Sim et al., 2013; Bettiol et al., 2018b; James et al., 2019; Zheng et al., 2020).

Several limitations can be found in this study. Because the study was conducted at a single health center, the views and opinions of study participants may not fully represent those of the other breastfeeding women. In addition, a recall bias can exist due to the retrospective design of the study. Lastly, cross-sectional data only provides information regarding the association between HM use and potential predictor variables. However, this is the first study to document the pattern of HM use among breastfeeding mothers in Tanzania and identify the factors that are significantly associated with HM use.

There is a high prevalence of HM use among breastfeeding mothers in Tanzania to overcome various problems with breastfeeding. Appropriate HM use can be used as one of the strategies to achieve EBF as it can help nursing mothers from resource-limited countries to tackle common breastfeeding challenges and practice optimal feeding behavior. However, the effectiveness and safety of the most commonly used HM among nursing mothers rely on anecdotal evidence rather than clinical, and this awakens the need to evaluate HM’s safety and efficacy through pharmacological studies for scientific evidence. In addition, despite the popular use of HM among nursing mothers, no guideline has been established in clinical settings to promote open dialogues between the healthcare providers and mothers to ensure the safe use of HM. This puts emphasis on the development of public awareness program to encourage active patient-physician communication and facilitate proper HM use.