Fig. 3

The Q‒Q plot for association with NVP. (a–e)The Q‒Q plot with the NVP variable as (a) binary 1 (“no” vs. “nausea only”, “vomited but could eat,” and “vomited and could not eat”), (b) binary 2 (“no” and “nausea only” vs. “vomited but could eat” and “vomited and could not eat”), (c) binary 3 (“no”, “nausea only,” and “vomited but could eat” vs. “vomited and could not eat”), (d) binary 4 (“no” vs. “vomited and could not eat”), and (e) continuous (regarding four categories as consecutive severity grading) at the discovery stage. (f–j) The Q‒Q plot with the NVP variable as (f) binary 1, (g binary 2, (h) binary 3, (i) binary 4, and (j) continuous at the replication stage. NVP, nausea and vomiting of pregnancy