Since October, at least five other Guatemalans have suffered broken bones and other serious injuries after falling from the border wall, Paniagua said.
Authorities also have interdicted seven tractor trailers with migrants hiding inside since January, he said, after recording just 12 such incidents in all of 2019.
"This is a very worrisome trend," he said.
"People are taking more and more risks, and they're losing their lives."
During the 2019 fiscal year, US authorities took more than 470,000 migrants into custody who arrived as part of a family group amid a record influx of Central Americans claiming a fear of persecution in their home countries.
The Trump administration has responded with an array of measures that have all but closed the southern border to asylum seekers, while sending at least 60,000 to Mexico to wait outside US territory while their cases are processed.
Those measures have led to a 75 per cent drop in border detentions since May, US authorities say, even as the latest figures show a slight uptick in the number of single Mexican adults and unaccompanied minors attempting to cross.
With the addition of taller and more formidable barriers along the border, including more than 135 miles of new 30-foot-tall bollard fencing the Trump administration has installed, smuggling organisations have been using improvised ladders to take migrants over the top.
The tactic requires migrants to cling to the top of the structure, then climb a ladder down the other side or slide down by wrapping their arms and legs around the steel. The move requires a significant degree of athleticism.
Girón Luna was a social worker and beauty pageant winner in her hometown in Guatemala's Quetzaltenango department, according to Paniagua and social media posts from friends mourning her death. Her friends said she made the journey to the border to support her family financially.
Girón Luna slipped while trying to descend from the top of the barrier, Paniagua said, landing on her back. The teen's partner, Dilver Israel Díaz García, 26, carried her away from the scene seeking help and encountered US Border Patrol agents, who radioed for an ambulance.
Doctors in El Paso were unsuccessful in trying to deliver the child via Caesarean section, and Girón Luna underwent multiple surgeries before dying, Paniagua said. Díaz García remains in US Border Patrol custody, where he faces deportation.
In a conference call with reporters Thursday, US Customs and Border Protection acting commissioner Mark Morgan described Girón Luna's fatal fall in detail, calling it "an example of the truth" of what's occurring at the border.
"The smugglers quickly left them alone, fading off in the darkness, leaving them to make the final legs of the journey by themselves," he said.
"As they attempted to climb the wall, the husband could do nothing but watch as he saw his pregnant wife fall to the ground.
"This is absolutely tragic," Morgan said.
"But what is also part of the tragedy is what's preventable. Do not listen to the smugglers. They do not care about you. They will abuse you and they will leave you behind to die. That is the truth. Those are the facts."
CBP officials have not released data indicating how many injuries there have been along the barrier in recent months. Two Guatemalan teens suffered significant injuries after falling from an 18-foot span of fencing in Arizona in 2018, an incident recorded by CBP video cameras.
