Letter: X

Pyridoxine/doxylamine combination products are licensed for the treatment of nausea and vomiting in pregnancy (NVP). In the UK, a delayed-release preparation is marketed as Xonvea, in the US as Diclegis, and in Canada as Diclectin.

Where treatment with anti-emetics is required for NVP, the Royal College of Obstetricians and Gynaecologists (RCOG) recommend cyclizine, promethazine, prochlorperazine, chlorpromazine or Xonvea as potential first-line options. Ondansetron or metoclopramide can be considered as second-line treatments.
Risk of infant congenital malformation following in utero exposure to products containing pyridoxine/doxylamine have been widely studied, with the majority of analyses providing no evidence of an increased risk. Data relating to other pregnancy outcomes are more limited but do not provide compelling evidence of adverse fetal effects.

Exposure to pyridoxine/doxylamine at any stage in pregnancy is not regarded as medical grounds for termination of pregnancy, nor does it require any additional fetal monitoring. However, other risk factors may be present in individual cases which may independently increase the risk of adverse pregnancy outcome. Clinicians are reminded of the importance of consideration of such factors when performing case-specific risk assessments.