We exploit the difference in means of postnatal hospital stays between beneficiary mothers of Janani Suraksha Yojana (JSY) and control mothers to estimate causal effects of postnatal hospital stay on postdischarge complications of a mother and her newborn. We argue that JSY increases the demand for institutional deliveries in those hospitals, which are assigned by the government to provide such services to the JSY recipients. Given the limited supply of beds, health professionals and other facilities, an excess demand for institutional deliveries in those hospitals forces JSY recipients to stay for a shorter time after birth compared with nonrecipients of JSY who are free to deliver in any hospital. Thus, the dummy for JSY becomes a suitable instrument for postnatal hospital stay. Using instrumental variables (IV) regressions, we find that postnatal hospital stay has statistically significant negative causal effects on half of the available postdischarge complications in the data, including abdominal pain, vaginal discharge, convulsion and severe headache of a mother and fever or cold of the newborn.