Q. How long after the birth of the baby girl can the mother still say Shehecheyanu? (See question 3133).
A. Mishna Berura (223: 3) quoting P’ri Megodim maintains one can recite the brocho as long as she feels the novelty. Teshuvos Vehanhogos (1: 200) explains that it is as long as the parents engage in telling relatives and friends the good news.
However, Mor Uketzia (224) asserts that it should not be recited after three days,
Horav Shlomo Miller’s Shlit’a opinion is that it can be recited for even thirty days after the birth.
Rabbi A. Bartfeld as advised by Horav Shlomo Miller and Horav Aharon Miller Shlit’a