Ginger, vitamin B6 , or neither for nausea during pregnancy?

Nausea and vomiting of pregnancy (NVP) is a common symptom experienced in up to 90% of pregnancies during the first trimester^[1]. Its typical course is depicted in Figure 1. Often referred to as “morning sickness,” evidence shows that NVP does not typically^[2] occur only in the morning. Although most cases of NVP are mild and self-limiting, more severe nausea and vomiting can occur. And whether it’s mild or sever, it is a distressing aspect of early pregnancy. In fact, NVP can decrease a woman’s desire to consider future pregnancies.^[3] 

The causes of NVP are unknown, though they are considered to be hormonal and specifically related to human chorionic gonadotropin (hCG) due to the occurrence of NVP in some women who have molar pregnancies, which are noncancerous tumors that form in some nonviable pregnancies. Since hCG is produced by the placenta and induced by molar pregnancies even in the absence of a viable fetus, this strongly suggests that hCG or other placental factors are contributors to NVP. In addition, women are at higher risk for NVP if they have higher hCG levels, such as those seen in women pregnant with twins or fetuses with Down syndrome^[2]. Fortunately, mild to moderate NVP is not associated with risks for the pregnancy, and may serve ^[4]a protective role.

Severe morning sickness or NVP is referred to as (hyperemesis gravidarum (HG)^[5]. It is diagnosed when vomiting is quite severe and the mother is at risk for electrolyte imbalances. Severe HG can endanger a pregnancy if not treated carefully.

For both forms of morning sickness, NVP and HG, supportive methods are recommended^[6] until the illness passes. For HG, these methods may be more intensive and require IV fluid replacement and hospitalization. For NVP, solutions can start with dietary changes, such as eating bland foods, and then may progress to supplements and pharmacological treatments. Pharmaceutical options typically include the antiemetic doxylamine. If dietary or lifestyle changes do not relieve symptoms, an alternative solution has been supplementation of pyridoxine (vitamin B₆), or a combination of vitamin B₆ with doxylamine. Ginger has also been recommended for soothing NVP.

Perhaps unsurprisingly, many people prefer non-pharmaceutical solutions for moderate NVP, when possible. One possibility lies in vitamin B₆, which some medical professionals have touted^[7] as useful for NVP since the 1940s. Another non-pharmaceutical remedy, long regarded as a folk remedy for nausea, is ginger. Ginger and ginger supplements are sometimes recommended for treating NVP^[2]. However, the totality of the evidence for ginger remains unclear.^[8] In the examined study, researchers compared the effects of ginger to vitamin B₆ and placebo to assess their effect on NVP.

Incidence of nausea and vomiting during pregnancy is high, with up to 90% of women experiencing these symptoms during the first trimester. For up to 3% of women, severe nausea and vomiting, called hyperemesis gravidarum, results in a more serious illness that can require hospitalization and IV fluids. For mild to moderate NVP, a combination of lifestyle, supplementation, and pharmaceutical interventions are used, including vitamin B₆ and ginger. However, the effectiveness of vitamin B₆ and ginger remains unclear.