TABLE 1—

Live Birth Analysis, Complete Population, 14 Counties Most Affected by Hurricane Katrina: Alabama, Louisiana, and Mississippi, 2004–2006

	No. of Births			Incidence (No. Cases)			Required Risk in Missing Births to Indicate a Harmful Effect of the Storm	Ratio of Risk in Missing Births to Observed Risk
	Before Katrina	After Katrina	Difference (“Missing”)	Before Katrina	After Katrina	Observed Baseline RR (95% CI)
Overall region	34 520	27 848	6 672
VPTB				0.031 (1070)	0.028 (780)	0.90 (0.82, 0.99)	0.057	2.02
PTB				0.167 (5765)	0.167 (4651)	1.00 (0.97, 1.04)	0.195	1.17
VLBW				0.021 (725)	0.020 (557)	0.95 (0.85, 1.06)	0.037	1.85
LBW				0.110 (3797)	0.108 (3008)	0.98 (0.94, 1.03)	0.143	1.31
Louisiana	21 361	14 932	6 429
VPTB				0.032 (684)	0.024 (358)	0.75 (0.66, 0.85)	0.062	2.58
PTB				0.161 (3439)	0.154 (2300)	0.96 (0.91, 1.00)	0.200	1.30
VLBW				0.023 (491)	0.018 (269)	0.78 (0.68, 0.91)	0.044	2.43
LBW				0.110 (2350)	0.105 (1568)	0.95 (0.90, 1.01)	0.142	1.35

Note. CI = confidence interval; LBW = low birth weight; PTB = preterm birth; RR = relative risk; VLBW = very low birth weight; VPTB = very preterm birth.

Source. Baseline numbers and risks taken from National Vital Statistics Reports.¹¹