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

BMC Neurology

Table 3 Comparison between high-frequency and low-frequency perimenstrual headache (variables with statistical difference)

	N (%) or Median (IQR)		P
	Low-frequency perimenstrual headache N = 155	High-frequency perimenstrual headache N = 99	P
Headache duration
Shorter than 4 h	45 (29.0)	12 (12.1)	0.002^a**
Longer than 4 h	110 (71.0)	87 (87.9)
Frontal
No	108 (69.7)	56 (56.6)	0.033^a*
Yes	47 (30.3)	43 (43.4)
Phonophobia
No	87 (56.1)	38 (38.4)	0.006^a**
Yes	68 (43.9)	61 (61.6)
Pain intensity^c
Mild	72 (46.5)	31 (31.3)	0.017^a*
Moderate to severe	83 (53.5)	68 (68.7)
Need pain killer
No	135 (87.1)	72 (72.7)	0.004^a**
Yes	20 (12.9)	27 (27.3)
Onset of headache^d
Before day 1	42 (27.1)	41 (41.4)	0.037^a*
On day 1	75 (48.4)	34 (34.3)
After day 1	38 (24.5)	24 (24.2)
Migraine
No	124 (80.0)	68 (68.7)	0.041^a*
Yes	31 (20.0)	31 (31.3)
Migraine score^e	4 (2,4)	4 (3,5)	0.003^b**
Perimenstrual symptoms^f
Extremity Swelling	37 (23.9)	37 (37.4)	0.021^a*
Generalized pain	55 (35.5)	53 (53.5)	0.005^a**

^*p < 0.05, **p < 0.01
^aChi-squire
^bMann-Whitney U test
^cPain intensity is evaluated by Visual Analogue Scale (VAS), mild (1–3), moderate (4–6), severe (7–10)
^dOnset of headache defines the first day of bleeding as day 1 and the day before bleeding as day-1 (consisting with ICHD-3)
^eMigraine 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
^f27 perimenstrual symptoms were surveyed in total, perimenstrual symptoms refers to whether had certain symptom between 7 days before menstruation and the end of menstruation in the last year

ISSN: 1471-2377