Search strategy and selection criteria
The clinical trial data registered in the Drug Clinical Trial Registration and Information Disclosure Platform (http://www.chictr.org.cn/) and ChiCTR (http://www.chinadrugtrials.org.cn) are collected21,22.Criteria for data inclusion: ”valid” clinical trials between January 1, 2013 and June 30, 2020 involving medical intervention in pregnant women who intend to continue pregnancy. Trials completed in early 2013 and those having not finished enrollment in June 2020 were also included. Use the registry search function to search any of the following terms in the following names: ”Obstetrics”, ”Pregnancy”, ”Pregnant”, ”Fetus”, ”Birth”, ”Perinatal”, ”Newborn”, ”Postpartum”, ”Prenatal”, ”Maternal”, ”Maternity”, ”Mother” or ”Birth Outcome”. This investigation included clinical trials of traditional Chinese medicines, supplements, and vitamins (figure 1).