A New Jersey “miracle baby” with a rare, life-threatening skull condition wasn’t expected to live more than a day, but now he’s almost 7 months old — and the first such case in the world to survive.

Maria Santa Maria, of Garfield, gave birth to her son Lucas on March 7 knowing that he had a condition called exencephaly — meaning he is missing a large area of his skull — and that the prognosis was very poor.

The 30-year-old mom found out about her son’s condition during her first ultrasound when she was 10 weeks pregnant and was told he might not live past the day of his birth.

“The doctor tried to explain he had exencephaly — his skull hasn’t completely closed,” Santa Maria told The Post on Wednesday. “He said the baby’s brain was protruding, which is incompatible with life, and they recommended abortion.”

She and her husband, Augusto Santa Maria, 31, had a major decision to make.

“I was never for abortion but we were for considering the circumstances,” she said. “It was always a battle back and forth. I was always researching everything I could about it. I decided even if I could be with him for even five minutes, it would all be worth it.”

She prepared her three daughters, ages 3, 7 and 8, for what she thought would be their baby brother’s first and last day and told them to pray for him, she said.

The girls were present in the delivery room when Lucas was born.

“They were waiting for him to pass,” Santa Maria said.

Instead, Lucas made so much progress in the neonatal intensive care unit that the family was allowed to take him home. But his parents felt he wasn’t ready.

“What he had on his head was a big balloon like twice the size of his head,” his mother said. “If that ruptured, it was a big emergency. We couldn’t handle him like that. We asked what other options we had, and that’s when [the doctor] came in and started explaining to us the surgery … And as soon as he started talking about that, we knew it was the route we wanted to take.”

Lucas pulled through the groundbreaking surgery performed by doctors at the North Jersey Brain and Spine Center, including Dr. Tim Vogel.

Vogel and his team wanted to do all they could to grant the family’s wish — to hold their baby before he died.

In most cases of exencephaly that isn’t possible because any physical contact risks damaging the fragile layer of cells that protect the baby’s brain from the world.

“I had to push for the first couple days [for] the surgery to get done,” Vogel said. “I think it was an amazing amount of fortitude [the family] had in looking forward to that.”

Amazingly, Lucas was allowed to go home only a week after the procedure.

Another surgery is forthcoming in five to six months, in which doctors will reconstruct his skull, according to Vogel.

“There’s no script to follow,” he said. “Every moment that we have with Lucas is a blessing, so I don’t know what he’s going to be able to do. The fact that he’s able to do what he’s doing now is awesome.”

Lucas has been going to physical therapy, as well as eating cereal and baby food, his mom said. His sisters enjoy singing to him and kissing him.

“He came to complete our family because this is the baby boy we’ve been waiting for,” Santa Maria said.