The multi-year Tsepamo study in Botswana was initially designed to assess the risk of neural tube defects associated with efavirenz. However, interim results published in 2018 reported an increased prevalence of 0.94% in women on dolutegravir-based regimens at conception vs 0.12% in women on other ART regimens.

The sample size was relatively small, and the researchers could not determine confidently if this was a real risk. Further follow-up time to March 2019 resulted in a prevalence of neural tube defects of 0.3% in those women conceiving on dolutegravir vs 0.1% in those women on other ART regimens.

Now another year of follow-up has been added and the results were presented at the AIDS 2020 Virtual conference last month. The prevalence of neural tube defects in women on dolutegravir-based regimens appears to have stabilised at 0.2%, which is not a statistically significant difference to the prevalence in women on other ART regimens.

Current NDoH guidelines recommend avoiding dolutegravir for the first 6 weeks of pregnancy (until the neural tube has closed). You can find the full presentation on the conference website.