On his touchdown scoring play, Goodwin had Giants' corner Janoris Jenkins beat and ran the last 20 yards untouched to the end zone alone.
Goodwin told his social-media followers that the baby boy was delivered at 4 a.m. Sunday after "some complications".
Morgan Goodwin also posted on Instagram that she had to deliver her "precious baby boy early this morning due to pre-term labor".
Goodwin continued, "Although we are hurt, I am grateful for the experience and grateful that God blessed me with a wife as courageous and resilient as Morgan. The pain (physically, mentally, & emotionally) that she was endured is unbelievable", he continued.
Quarterback C.J. Beathard connected with Goodwin on an 83-yarder that was the team's longest TD pass in 12 years and contributed to San Francisco's first win of the season.More news: Arab teams in the World Cup For the first time in history
Goodwin left the team's locker room quickly after the game to return to his family, NBC Sports reported.
The couple had announced the pregnancy in September, posting a photo of them holding a sonogram image as they kissed.
Goodwin is one of the fastest players in the National Football League, a great sprinter and member of the 2012 U.S. Olympic Team; he was one of three men's long jumpers representing the country. "He had a wonderful game today".
Goodwin did not speak with the press after the game but revealed the tragedy in a heartbreaking Instagram post later in the day.
Prayers to Marquise Goodwin, his wife, Morgan, and their entire family for their tragic loss.