TABLE 5.

Effects on prematurity for mothers with different characteristics (models with mother fixed effects and 39 weeks IV)

Mom CHAR:	HS or less	Black	Hispanic	Over 35	Teen mom	Smoking
Panel A: Cluster S.E. on mother
Any chem.	− 0.0020	− 0.0003	0.0023	0.0024	0.0021	0.0014
	(0.0024)	(0.0020)	(0.0022)	(0.0020)	(0.0019)	(0.0019)
* Mom CHAR	0.0090**	0.0111**	− 0.0005	− 0.0044	− 0.0029	0.0192
	(0.0038)	(0.0052)	(0.0042)	(0.0089)	(0.0246)	(0.0122)
R-squared	0.0000	− 0.0000	− 0.0000	− 0.0000	− 0.0000	− 0.0000
Any contam.	− 0.0005	0.0005	0.0028	0.0027	0.0024	0.0018
	(0.0022)	(0.0018)	(0.0020)	(0.0018)	(0.0017)	(0.0017)
* Mom CHAR	0.0068+	0.0097+	− 0.0015	− 0.0056	− 0.0084	0.0166
	(0.0035)	(0.0049)	(0.0039)	(0.0075)	(0.0239)	(0.0109)
No. observations	521978	521978	521978	521978	521978	521978
Panel B: Cluster S.E. on water district and year
Any chem.	− 0.0018	− 0.0002	0.0025	0.0025	0.0023	0.0016
	(0.0024)	(0.0022)	(0.0026)	(0.0024)	(0.0024)	(0.0023)
* Mom CHAR	0.0091***	0.0115**	− 0.0007	− 0.0044	− 0.0031	0.0197**
	(0.0028)	(0.0046)	(0.0032)	(0.0061)	(0.0183)	(0.0087)
Any contam.	− 0.0004	0.0006	0.0030	0.0029	0.0026	0.0019
	(0.0020)	(0.0019)	(0.0022)	(0.0021)	(0.0020)	(0.0020)
* Mom CHAR	0.0069**	0.0100**	− 0.0017	− 0.0056	− 0.0087	0.0171**
	(0.0027)	(0.0044)	(0.0030)	(0.0051)	(0.0176)	(0.0077)
No. observations	521978	521978	521978	521978	521978	521978

NOTES: See table 3 notes. Mother characteristics are measured as of the first birth. Robust standard errors are clustered on the mother.