Table 4.

Effects of Hurricane Within 30km on Birth Outcomes - Different Estimators

	Low Birth Weight (<2500g)	Gestation (weeks)	Any Abnormal Conditions (1996–2004)	Any Complications of Labor/Delivery (1996–2004)
A. OLS with County Fixed Effects - Counting Backward from the Birth Date to Estimate Exposure

Hurricane 1st Trimester	−0.0020 (0.0045)	−0.0225 (0.0484)	0.0175 (0.0185)	−0.0019 (0.0102)
Hurricane 2nd Trimester	−0.0038 (0.0069)	−0.0102 (0.0578)	0.0152 (0.0167)	0.0128 (0.0175)
Hurricane 3rd Trimester	0.0155^** (0.0060)	−0.1047 (0.0821)	0.0400^** (0.0121)	0.0266^*** (0.0064)

B. OLS with County Fixed Effects - Counting Forward from Conception to Estimate Exposure

Hurricane 1st Trimester	−0.0076 (0.0050)	0.0108 (0.0635)	0.0115 (0.0219)	−0.0003 (0.0075)
Hurricane 2nd Trimester	0.0031 (0.0081)	−0.1142^** (0.0496)	0.0228 (0.0148)	0.0141 (0.0159)
Hurricane 3rd Trimester	−0.0004 (0.0057)	0.1613^** (0.0516)	0.0346^*** (0.0093)	0.0183^** (0.0090)

C. IV with Mother Fixed Effects - Counting Forward from Conception to Estimate Exposure

Hurricane 1st Trimester	−0.0021 (0.0100)	−0.0378 (0.0703)	0.0363^** (0.0137)	0.0213 (0.0195)
Hurricane 2nd Trimester	−0.0022 (0.0093)	−0.0424 (0.0687)	0.0136 (0.0142)	0.0237 (0.0193)
Hurricane 3rd Trimester	0.0005 (0.0089)	0.1210^** (0.0578)	0.0341^** (0.0136)	0.0448^** (0.0184)

D. IV with Mother Fixed Effects - Full Term Gestation Exposure Instrument

Hurricane 1st Trimester	−0.0021 (0.0100)	−0.0378 (0.0703)	0.0363^** (0.0137)	0.0213 (0.0195)
Hurricane 2nd Trimester	−0.0021 (0.0093)	−0.0433 (0.0687)	0.0136 (0.0142)	0.0237 (0.0193)
Hurricane 3rd Trimester	0.0089 (0.0100)	−0.0431 (0.0649)	0.0389^** (0.0147)	0.0409^** (0.0196)

E. IV with Mother Fixed Effects - Full Term Gestation Exposure Instrument

Hurricane Any Time During Pregnancy	0.0020 (0.0057)	−0.0416 (0.0392)	0.0291^*** (0.0083)	0.0287^** (0.0113)

F. IV with Mother Fixed Effects - Placebo Models

Hurricane 6 mo. After Birth	−0.0114 (0.0080)	0.0748 (0.0554)	0.0107 (0.0124)	−0.0099 (0.0177)

N	485,048	485,111	301,683	301,683

Notes: Each column in each panel is a separate regression. See notes under Table 1 for information on the sample. For each outcome, births by mothers who have at most one child with non-missing data for that outcome are omitted. In Panels A and B, exposure to the storm or hurricane is calculated by counting trimesters backward from the child’s date of birth. In all the other panels, exposure to the storm or hurricane is calculated by counting trimesters forward from the date of conception.

Panels A and C present results from OLS regressions that include controls for mother’s race (non-Hispanic white, black, Hispanic, Hispanic missing), mother’s age (<20, 20–24, 25–34, 35–44, 45+), mother’s education (<HS, HS, some college, college+, missing), mother’s marital status (married, not married, marital status missing), birth order, as well as conception year, conception month, and county fixed effects, and an indicator for living within 30km of an area that was ever affected by a storm or hurricane over the time period of analysis. Robust standard errors in Panels A and C are clustered on the county level. Panels B, D, E, F, and G present results from regressions with mother fixed effects where the key coefficients of interest are instrumented by indicators for a storm/hurricane at the time of the current pregnancy within a 30km radius of the mother’s first pregnancy residence. Additionally, the instrument in Panels E and F (“Full term Gestation Exposure Instrument”) assumes that the pregnancy lasts 39 weeks. These regressions include time-varying controls for mother’s age, mother’s education, mother’s marital status, birth order, as well as conception year and conception month fixed effects, and an indicator for living within 30km of an area that was ever affected by a storm or hurricane over the time period of analysis. Robust standard errors in Panels B, D, E, F, and G are clustered on the mother.

Significance levels:

⁺

p<0.10

^**

p<0.05

^***

p<0.001