Table 3.

Studies included in systematic evidence map for hyperemesis gravidarum, presented according to their method

Method*	Number of studies	Method subcategory	Number of studies
Reviews	34	Systematic review	25
		Literature review	9
RCT†	21
Cohort studies	85	Prospective cohort study	41
		Retrospective cohort study	44
Case–control studies	124	Prospective case–control study	109
		Retrospective case–control study	15
Qualitative study†	9
Surveys†	13
Case reports/Series	125	Case reports	115
		Case series	10
Total	411

*RCT, qualitative studies and surveys did not require subcategories.

†Method categories were not mutually exclusive.

RCT, randomised control trial.