US Vice President JD Vance has announced the birth of his fourth child, a boy, with his wife, Usha Vance.

Alec Neel Vance was born on Sunday morning, the vice-president said in a statement on social media.

“Usha and the baby are happy and healthy, and our kids are overjoyed to meet their little brother,” he added, also thanking the military doctors and staff at Walter Reed Medical Center for their care.

It is the first time a baby has been born to a sitting vice-president while in office for more than 150 years, according to the Associated Press.

The pair have three other children: Ewan, 9, Vivek, 6, and four-year-old Mirabel.

Usha Vance was born and raised in the working-class suburbs of San Diego, California, to a father who was a mechanical engineer and a mother who was a molecular biologist, both of whom had moved to the US from India.

She met JD Vance as a student at Yale Law School in 2010, when they joined a discussion group on "social decline in white America".

Usha Vance (née Chilukuri) was born and raised in the working-class suburbs of San Diego, California, to a mechanical engineer father and a molecular biologist mother who had moved to the US from Andhra Pradesh, India.

JD Vance has been one of the most vocal members of the Trump administration in calling for higher birth rates in the US.

He wrote in his recently published book that Usha had initially been reluctant to have another child but that her mind changed after conservative influencer Charlie Kirk was killed last year.

"Not long after we buried my friend, she became pregnant with our fourth child, a boy," he wrote. "One life was stolen from us, but another was given."