The role of purity and frequency in the classification of perimenstrual headache

BMC Neurology

Table 4 Comparison between pure and impure perimenstrual headache (variables with statistical difference)

	N(%) or Median(IQR)		P
	Impure perimenstrual headache N = 147	Pure perimenstrual headache N = 107	P
Onset of headache^c
Before day 1	58(39.5)	25(23.4)	0.024^a*
On day 1	58(39.5)	51(47.7)
After day 1	31(21.1)	31(29.0)
Location number^d
Single	61(41.5)	65(60.7)	0.002^a**
Multiple	86(58.5)	42(39.3)
Phonophobia
No	65(44.2)	60(56.1)	0.062^a*
Yes	82(55.8)	47(43.9)
Pain intensity^e
Mild	51(34.7)	52(48.6)	0.026^a*
Moderate to severe	96(65.3)	55(51.4)
Migraine score^f	4(3, 5)	4(2, 5)	0.012^b*

^*p < 0.05, **p < 0.01
^aChi-squire
^bMann-Whitney U test
^cDay of onset of headache defines the first day of bleeding as day 1 and the day before bleeding as day-1 (consisting with ICHD-3)
^dLocation number defines the same location of the bilateral head as single, different location as multiple, representing the diversity of affected head location
^ePain intensity is evaluated by Visual Analogue Scale (VAS), mild (1–3), moderate (4–6), severe (7–10)
^fMigraine score: duration 4-72 h = 1, unilateral = 1, moderate to severe = 1, throbbing = 1, aggravation with activity = 1, nausea = 1, vomiting = 1, photophobia or phonophobia = 1

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