Article 1: Biophysical Effects, Safety, and Efficacy of Raspberry Leaf Use in Pregnancy: A Systematic Integrative Review

Abstract:

Background: Childbearing women have been using various herbs to assist with pregnancy, labor and birth for centuries. One of the most common is raspberry leaf. The evidence base for the use of raspberry leaf is however under-developed. It is incumbent on midwives and other maternity care providers to provide women with evidence-based information so they can make informed choices. The aim of this study was to review the research literature to identify the evidence base on the biophysical effects, safety and efficacy of raspberry leaf in pregnancy.

Methods: A systematic, integrative review was undertaken. Six databases were searched to identify empirical research papers published in peer reviewed journals including in vitro, in vivo, human and animal studies. The search included the databases CINAHL, MEDLINE, Cochrane Library, Scopus and Web of Science Core Collection and AMED. Identified studies were appraised independently by two reviewers using the MMAT appraisal instrument. An integrative approach was taken to analysis.

Results: Thirteen studies were included. Five were laboratory studies using animal and human tissue, two were experiments using animals, and six were human studies. Included studies were published between 1941 and 2016. Raspberry leaf has been shown to have biophysical effects on animal and human smooth muscle including the uterus. Toxicity was demonstrated when high doses were administered intravenously or intraperitoneally in animal studies. Human studies have not shown any harm or benefit though one study demonstrated a clinically meaningful (though non-statistically significant) reduction in length of second stage and augmentation of labor in women taking raspberry leaf.

Conclusions: Many women use raspberry leaf in pregnancy to facilitate labor and birth. The evidence base supporting the use of raspberry leaf in pregnancy is weak and further research is needed to address the question of raspberry leaf’s effectiveness.

Type of Study: Systematic Review

Summary:

                  This article focuses on the use of raspberry leaf in pregnancy as well as fetal outcomes. Raspberry leaf is associated with smooth muscle relaxation which, according to some studies, is particularly helpful during the active and latent phases of labor. One study conducted by Whitehouse demonstrated that raspberry leaves can relax the uterus without impacting blood pressure. While this is a significant finding, there are also unfavorable side effects associated with this product. For instance, in another study reported by Nguyen, women with gestational diabetes developed hypoglycemia after consuming 16 oz of raspberry tea leaf a day for 3 days. Care should be taken in women who are using insulin to manage their gestational diabetes as it may potentiate worsening hypoglycemia. Some women, however, may want to raspberry leaf to manage their gestational diabetes, though they must be monitored extremely closely.  Another study included in this article reported findings which demonstrated alterations of the CYP in offspring of mothers who used this herb during pregnancy. Other studies focused on the effect of raspberry leaf on pregnancy outcome. For one study, researchers documented increased incidence of c-section births in women using this herb. However, there were “no statistically significant differences” in between women who used raspberry leaf and women who didn’t where APGAR score, diastolic blood pressure, meconium-stained liquor, transfer to neonatal ICU, and postpartum hemorrhage were concerned. There were also no differences for other factors either such as labor augmentation, epidural, length of the stages of labor, etc. There is not enough evidence to indicate that use of this herb is beneficial in pregnancy and more research must be conducted before a definitive conclusion is established.