Comparing pyridoxine and doxylamine succinate-pyridoxine HCl for nausea and vomiting of pregnancy: A matched, controlled cohort study.

Nausea and vomiting of pregnancy (NVP) is a common gestational condition. This is the first study to compare the use of vitamin B6 (pyridoxine) versus Diclectin (doxylamine succinate–pyridoxine HCl) for NVP symptoms. Participants were pregnant women with NVP who used either pyridoxine or doxylamine succinate–pyridoxine HCl for ≥4 days prior to calling the Motherisk NVP Helpline. Women receiving pyridoxine only (n = 80) were matched to a woman taking doxylamine succinate–pyridoxine HCl only (n = 80), accounting for potential confounders and baseline level of NVP, measured by the Pregnancy Unique Quantification of Emesis (PUQE) score. Change in NVP severity after a week of therapy with either pyridoxine or doxylamine succinate–pyridoxine HCl was quantified using the PUQE-24 scale, which describes NVP symptoms 24 hours prior to their call. Doxylamine succinate–pyridoxine HCl use found a significant reduction in PUQE score, compared with pyridoxine (+0.5 versus -0.2, P < .05; negative denotes worsening). This association was especially prominent in women with more severe symptoms, where doxylamine succinate–pyridoxine HCl use saw a mean improvement of 2.6 versus 0.4 with pyridoxine (P < .05). As well, doxylamine succinate–pyridoxine HCl use was associated with fewer women experiencing moderate to severe scores after a week of treatment, compared with the pyridoxine group (7 versus 17, P < .05), despite similar baseline PUQE scores.