Table 3.

Instrumental variable estimate of the effect of breastfeeding exclusivity on child obesity status at age 2

	First stage Weeks breastfed	First stage Weeks Breastfed Exclusively	IV estimates Child overweight	IV estimates Child obese
Weeks breastfed		−0.01	−0.008* [−.024 – .004]	[−.018 – .001]
Weeks breastfed exclusively		−0.008	−0.0066* [−.019 – .003]	[−.014 – .001]
My baby was fed only breast milk at the hospital	7.18* [1.04–13.33]	8.85** [5.00–12.78]
Observations	447	441	447	441
County FE	Yes	Yes	Yes	Yes
F-statistic of excluded instrument	5.73	21.94

Estimates from instrumental variables linear probability models.

Models control for mother’s income, mother’s education, mother’s employment, mother’s marital status, mother’s age, mother’s weight, mother’s height, mother’s weight gain during pregnancy, mother’s parity, number of prenatal visits, mother’s insurance status, mother’s gestational diabetes, child’s race, child’s birth weight, child’s ever being on WIC, father’s education and county of residence fixed-effects.

Weighted standard errors clustered at the county level in brackets.

^***p< 0.01.

^**p< 0.05.

^*p< 0.1.