In this study, we determined the magnitude of use of herbal medicines (HMs) during pregnancy or delivery. We also examined factors associated with the use of herbs among women who delivered a live-born baby between September 2016 and 2018, in Tabora, central Tanzania. Findings show that use of HMs during pregnancy or delivery is high (60%).
Worldwide, use of HMs has grown considerably among pregnant women, and particularly in sub-Saharan Africa . Similar to the findings in Tabora, the level of use of HMs is high in other areas of sub-Saharan Africa, Asia and Middle East, where the proportions of use range between 20% to 80% [9,11,22–24]. For many years, women use HMs for remedial of several conditions during pregnancy and in the delivery process. Findings from our study are consistent with reports from other countries that pregnant women use herbs for different purposes, including easing pain, accelerating labour, increasing milk production, and aiding postpartum uterine involution [13,22,25]. The grounds for the high usage of herbs could be attributed to their easy accessibility and the general lack of awareness of their potential side effects [26–28].
Women who perceive HMs as safe during pregnancy or delivery tend to use them more than those who perceive the herbs as unsafe [10,24,29]. In the current study, the prevalence ratios of using herbs were between 10% and 40% higher among women who perceived herbs as safe versus those who perceived them as unsafe. Despite the lack of significant association between perceived safety and use of HM during pregnancy, the assertion women have about safety of these herbs will only make scientific sense when the herbs are authentically tested, standardized, and quality controlled . Thus, the high-unchecked use of herbs especially in relation to pregnancy should invite a concern. It is even more serious as the unproven perceived safety can lead to rapid increase in promotion of traditional medicines in the society as well as the media. It is common to see posters advertising traditional medicines and herbalists in various parts of Tanzania. In such advertisements, HMs are often promoted as natural and safe, attracting their wide use, especially among pregnant women who are concerned about the whole process of childbirth and health of the unborn child.
Plants used for herbal remedies are less expensive as compared to modern medicines and they have been culturally considered as being effective and an acceptable option even when modern health facilities are available . Notwithstanding their easy availability and perceived effectiveness, many countries with high usage of herbs have also poor quality of health services and lower hygienic standards than countries with lower usage of herbs. However, some of these countries with high usage of HMs are also reporting high maternal and new born morbidity and mortality, suggesting a connection between use of herbs and adverse pregnancy outcomes. In rural Malawi for instance, where 25.7% of pregnant women used a popular herb, mwanamphepo, the odds of maternal morbidity were 28% higher among self-reported users than non-users of mwanamphepo. Furthermore, the probabilities of neonatal morbidity or death were 22% higher among neonates whose mothers reported use of the mwanamphepo than those who did not . Significantly higher odds of having postnatal complications have also been observed among women in Tanzania who reported use of local herbs during pregnancy or delivery versus those who did not . A report from Northern Italy also suggests an increased risk of giving birth to preterm babies among women who regularly rub almond oil on the pregnant abdomen compared with non-users . Although we cannot completely rule out the effect of pressure exerted on a pregnant abdomen through rubbing with herbs, the safety of any drug, including herbs, cannot be guaranteed in pregnancy because of the possible teratogenic effects .
Physical accessibility to health care facilities is an important attribute to using herbs during pregnancy [6,16,24,27,33]. In this study, women who reside far away (5 km or more) from the nearest health facility have almost 10% adjusted prevalence ratio of using HMs compared to women living closer to health facilities. However, the association between use of herbs and distance to facility in this study was not statistically significant, most probably due to the fact that participants were from an urban setting where health care facilities are concentrated. Despite this, long distances may contribute to women delivering under the care of unskilled attendants and hence exposure to the use of medicinal herbs. However, there might also be silent exposures even when a birth takes place in a health care facility. For instance, a study among healthcare professionals in Scotland revealed that a third of the respondents, significantly more midwives recommended use of complementary and alternative therapies to pregnant women .
Whereas response to high exposures to herbs during pregnancy or delivery is essential, the most important concern is lack of awareness and knowledge among pregnant women  and the community about potential side effects of using HMs on the mother and the fetus [6,35]. Findings from this study are similar to observations from other countries where self-medication with herbs during pregnancy or delivery is common but very few women attending antenatal care services receive information on their adverse effects. In Kenya for instance, merely 14% of pregnant women received health advice from healthcare workers . In the current study, compared to women who were advised by the maternity health care providers against the use of herbs during pregnancy or delivery, significantly (p=0.01) more women who did not receive such advice used herbs. This may suggest that if women get appropriate information during pregnancy they will greatly evade the use of herbs. In Tabora, all women received ANC services at least ones during the most recent birth, therefore presenting an opportunity to discuss the use of HM.
This study has several potential limitations that readers must consider when interpreting the findings. First, although we assumed that women who gave birth within the preceding two years were likely to remember use of HMs in their most recent pregnancy or delivery; we are unable to completely rule out the possibility of recall bias. If some women were unable to remember, this bias could have contributed to the low estimates. Second, some women were aware that use of HMs during pregnancy was discouraged by health care providers. Therefore, due to social desirability bias, there is a possibility that some respondents concealed reporting use of HMs, thus leading to under-estimating the proportion of HMs use. Third, there is possibility that the variables we considered as independent may not be exhaustive. Despite all these, to the best of our knowledge, this is the first study to attempt assessing use of HMs during pregnancy or delivery as a forgotten exposure when adopting strategies to attain the SDG 3 target on reduction of maternal and newborn mortality.