The onset of nausea and vomiting of pregnancy: a prospective cohort study

Abstract Background Nausea and vomiting are experienced by most women during pregnancy. The onset is usually related to Last Menstrual Period (LMP) the date of which often unreliable. This study describes time nausea symptoms from ovulation compares this last menstrual period Methods Prospective cohort seeking become pregnant, recruited 12 May 2014 25 November 2016, in United Kingdom. Daily diaries were kept 256 who trying conceive. main outcome measure number days or luteinising hormone surge until vomiting. Results Almost all (88%) had Human Chorionic Gonadotrophin rise within 8 10 ovulation; equivalent interval LMP was 20 30 days. Many (67%) experience 11 ovulation. Conclusions Onset occurs earlier than previously reported there a narrow window for symptoms. indicates that its etiology associated with specific developmental stage at foetal-maternal interface. Trial registration NCT01577147 . Date 13 April 2012