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

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

Nausea and vomiting in pregnancy is not just 'morning sickness': data from a prospective cohort study in the UK.

BACKGROUND: Nausea and vomiting in pregnancy is usually called 'morning sickness'. This is felt by sufferers to trivialise the condition. Symptoms have been described as occurring both before and after noon, but daily symptom patterns have not been clearly described and statistically modelled to enable the term 'morning sickness' to be accurately analysed. AIM: To describe the daily variation in nausea and vomiting symptoms during early pregnancy in a group of sufferers. DESIGN AND SETTING: A prospective cohort study of females recruited from 15 May 2014 to 17 February 2017 by Swiss Precision Diagnostics (SPD) Development Company Limited, which was researching hormone levels in early pregnancy and extended its study to include the description of pregnancy symptoms. METHOD: Daily symptom diaries of nausea and vomiting were kept by females who were trying to conceive. They also provided daily urine samples, which when analysed enabled the date of ovulation to be determined. Data from 256 females who conceived during the first month of the study are included in this article. Daily symptom patterns and changes in daily patterns by week of pregnancy were modelled. Functional data analysis was used to produce estimated symptom probability functions. RESULTS: There was a peak probability of nausea in the morning, a lower but sustained probability of nausea throughout the day, and a slight peak in the evening. Vomiting had a defined peak incidence in the morning. CONCLUSION: Referring to nausea and vomiting in pregnancy as simply 'morning sickness' is inaccurate, simplistic, and therefore unhelpful.