Comparison of the prevalence and severity of nausea and vomiting in the first trimester between singleton pregnancies conceived from stimulated in vitro fertilization and frozen embryo transfer cycles

OBJECTIVE: The objective of this prospective study is to compare the prevalence and severity of nausea and vomiting in the first trimester between singleton pregnancies conceived from stimulated in vitro fertilization (IVF) and frozen embryo transfer cycles (FET). METHODS: All women were recruited at 6 weeks gestation and filled in the modified Pregnancy-Unique Quantification of Emesis and Nausea (PUQE) to document whether they had any experience of nausea and vomiting weekly till 12 weeks gestation. The primary outcome was the prevalence of nausea and vomiting and the secondary outcomes included severity of nausea and vomiting and pregnancy outcomes. RESULTS: A total of 360 pregnant women were recruited and 171 were in the stimulated IVF group and 189 in the FET group. The overall return rate was 82.2% (81.8% in the stimulated IVF group and 82.5% in the FET group). Nausea and vomiting were worse in the FET group compared with the IVF group. There were significantly more women who felt nauseated or sick in the FET group (p value = 0.032 for week 11 and p value = 0.046 for week 12); significantly more women with a longer duration of nausea in the FET group (p value = 0.044 for week 7 and p value = 0.030 for week 8); significantly more women with more vomiting in a day in the FET group (p value = 0.042) and significantly more women with retching or dry heaves in the FET group (p value = 0.030 for week 8 and p value = 0.028 for week 11). CONCLUSION: Nausea and vomiting were significantly more prevalent and severe in the FET group when compared with the stimulated IVF group. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1186/s12884-022-05072-5.