Camille Freeman, CNS, LDN

A recent article by Nordeng et al studied the use of herbs during pregnancy by interviewing 600 women in a Norwegian hospital five days after the women gave birth. Almost 40% of the women interviewed reported herb use during pregnancy, with the most common choices listed as ginger, iron-rich herbs (I don’t have access to the full text; would love to know what these “iron rich” herbs were!), echinacea and cranberry. One interesting finding was a significant association between the use of raspberry leaf during pregnancy and Cesarean birth. I wouldn’t be surprised to find warnings about raspberry leaf (Rubus spp.) being dangerous in pregnancy popping up after this. As we know, however, association does NOT mean causation.

The fact raspberry leaf use and Cesarean were related in this study could mean several things, the most likely two being:

1) Use of raspberry leaf somehow increases risk for Cesarean. To prove this, we need to see more substantial evidence, hopefully from double blind, placebo-controlled RCTs. If this is true, we need to know how much raspberry leaf is needed to cause this effect, what form(s) are being used, at what point(s) in pregnancy, and of course WHY does this happen? We would also need to see evidence of this in other populations.

2) Women who use raspberry leaf are more likely to have a Cesarean due to other factors. It’s my GUESS that this is the case.  An example – one that I believe could well be true – would be that women who are approaching or past their “due date” and threatened with medical induction of labor. These women look for things they can do on their own to get labor started. In their search, they find information about red raspberry leaf being a late pregnancy tonic and give it a shot (most likely along with a host of other things, including long walks, sex, spicy foods..). It doesn’t work because a) red raspberry leaf doesn’t work like that that in the first place (see below) and b) their “due date” is incorrect and the baby is still cooking.  Once they go beyond their “due date” they are more likely to be induced, which increases the risk of a host of other interventions, including Cesarean.

So why do I think raspberry leaf is unlikely to work to stimulate labor? Check out this description from William Cook’s Physiomedical Dispensatory (1869):

“The leaves of the red raspberry are mildly astringent, and of a peculiarly soothing nature, being very acceptable to the stomach, always leaving a slight tonic impression, often allaying nausea and vomiting, and not unfrequently soothing and sustaining the nervous system … Dr. S. Thomson found it exerted a fine influence on the uterus, sustaining it in flagging labor; for which purpose he usually made it. into an infusion with cypripedium, and added a minute portion of capsicum when needed. It also anticipates flooding and relieves after-pains.”

Does that sound like something that would stimulate labor to you? Didn’t think so. Raspberry leaf is a very gentle medicine, and while it is found in many pregnancy teas, tonics and so forth, it’s more suited to gentle uterine toning than to stimulating labor. As far as potential to lead to Cesarean birth, that is another story.  Could it be so? Sure, could be. Is it worth considering? Yes, definitely. However, I’d like to see a lot more evidence before declaring Rubus spp. unsafe during pregnancy.