FORT LAUDERDALE, Fla. — A sharp increase in pregnant patients with COVID-19 has alarmed doctors, who held a news conference Tuesday to urge pregnant women to get vaccinated.

One woman died in the past week at Broward Health Medical Center in Fort Lauderdale, the first death among pregnant COVID patients at the four-hospital system. Other pregnant COVID patients have experienced difficulty breathing and complications in childbirth. The vast majority have been unvaccinated.

“What we’ve seen over the past several weeks has been an increase in the number of unvaccinated pregnant women that are coming into the hospital,” Dr. Joshua Lenchus, Broward Health’s interim chief medical officer, said in an interview. “Some of them are not faring very well.”

During past waves of the disease, one pregnant COVID patient would show up every three or five days, he said. Now they’re admitting three to five pregnant COVID patients per day.

Broward Health doctors are seeing “catastrophic scenarios unfold for some COVID-positive maternity patients,” the health system said in a statement Tuesday. “While caregivers saw complications during last year’s surge, the delta variant is proving exceptionally challenging for unvaccinated pregnant patients.”

The woman who died had “COVID-related complications with her breathing and getting enough oxygen, and she succumbed,” Lenchus said.

There have been 107,532 COVID cases among pregnant women in the United States as of Aug. 16, according to the U.S. Centers for Disease Control and Prevention. Of those, 18,262 were hospitalized and 128 died.

Pregnant women with COVID have suffered the same complications as others with severe cases, such as difficulty breathing, Lenchus said. They also suffer a higher risk of complications in childbirth, he said. Although the baby can’t contract COVID through the placenta, he said, there have been cases of babies getting COVID after birth from close contact with the mother or family members.

Lenchus said pregnant women appear to be vaccinated at a lower rater than others, possibly over disproven concerns about the vaccine’s effect on fertility or breastfeeding.

The Pfizer vaccine, one of three in use in the United States, received final approval Monday from the Food and Drug Administration, after having been administered in the U.S. under emergency-use provisions. The vaccine has been endorsed for use by pregnant women by the American College of Obstetricians and Gynecologists and the Society for Maternal-Fetal Medicine.

“It’s the single best preventive measure that will help them keep them safe from COVID during the rest of their pregnancy,” Lenchus said.

Broward Health currently has 420 patients hospitalized for COVID, of which 98 percent are not vaccinated, according to Jennifer Smith, spokeswoman for Broward Health.

Doctors have long considered pregnancy one of the factors that raises the risk of severe illness or death for those who contract COVID. Pregnant women with COVID stand a higher risk of requiring hospitalization, intensive care or breathing help from a ventilator, according to the CDC.