Table A3. Comparison of the frequency of deaths among pregnant and nonpregnant patients, according to data from 19th- and early 20th-century outbreaks*.

Reference	Nonpregnant		Pregnant
	Cases	Deaths	Cases	Deaths	p value*	OR (95% CI)†
Meyer (1), 1868–1872	1116	163	76	23	<0.01	2.5 (1.5–4.3)
van der Willigen (3), 1893–1894	352	39	80	12	0.33	1.4 (0.7–2.8)
Rao (6), 1959–1962	348	29	94	26	<0.01	4.2 (2.3–7.6)

*2-sided.
†OR, odds ratio; CI, confidence interval.