Table 2. Maternal clinical characteristics of suspected microcephaly cases, Salvador, Brazil, April 2015–July 2016 (n = 365).

Characteristics	Congenital brain abnormalities diagnosis				OR	95% CI	p value
	Confirmed (n = 166)		Excluded (n = 199)
	n/Na	%	n/Na	%
Mother’s age in years, median and IQRb	26	21–32	25	21– 31	NA	NA	0.38
Type of gestation
Multifetal	5/163	3.1	4/195	2.0	1.51	0.32–7.74	0.54
Single	158/163	96.9	191/195	98.0	1	NA
Symptoms during pregnancy
Feverc	66/155	42.3	42/187	22.5	2.56	1.56–4.21	< 0.001
Exanthema	118/161	73.3	68/193	35.2	5.04	3.12–8.19	< 0.001
Trimester of exanthemad
First trimester	75/108	69.4	25/57	43.9	2.91	1.42–5.97	0.001
Second or third trimester	33/108	30.6	32/57	56.1	1	NA
Other arboviral-infection-like symptoms reported during pregnancy
Pruritus	72/133	54.1	36/143	25.2	3.51	2.05–6.04	< 0.001
Arthralgia	60/135	44.4	31/143	21.7	2.89	1.66–5.06	< 0.001
Myalgia	51/135	37.8	25/142	17.6	2.84	1.58–5.17	< 0.001
Headache	48/133	36.1	25/142	17.6	2.64	1.46–4.83	0.001
Retro-orbital pain	24/133	18.1	6/142	4.2	4.99	1.89–15.38	< 0.001
Conjunctival hyperaemia	21/133	15.8	9/142	6.3	2.77	1.16–7.14	0.01

NA: not applicable; CI: confidence interval (95%); IQR: interquartile range; OR: odds ratio.

^a The denominators in this column may vary as they are based on the number of cases with known information on the characteristic in question.

^b Data on mothers’ ages were not available for nine confirmed and four excluded cases.

^c Fever was defined as axillary temperatures of ≥ 37.8 °C.

^d Data on trimester of exanthema are presented for the mothers who had exanthema (n = 118 for the mothers of confirmed congenital brain abnormality cases, and n = 68 for those of the excluded cases). For 10 confirmed and 11 excluded cases the trimester of the exanthema was unknown.