(CNN) -- A Texas woman got a quadruple Valentine's Day gift this year, giving birth to four babies -- two sets of identical twins.
Ace, Blaine, Cash and
Dylan Montalvo were born at the Woman's Hospital of Texas in Houston to
Tressa Montalvo, 36, and her husband, Manuel, 43, of Houston.
Ace and Blaine were
first, born at 8:51 a.m. and weighing 3 pounds, 10 ounces, and 3 pounds,
15 ounces, respectively, the hospital said. Cash and Dylan were a
minute later and weighed 2 pounds, 15 ounces and 3 pounds, 6 ounces. All
four were born by cesarean section.
"We tried to stick to the A-B-C-D theme when naming them," Tressa Montalvo said in a statement the hospital released.
The twins were not the
result of fertility treatments, the hospital said. Tressa Montalvo
learned she was carrying twins at 10 weeks.
A third heartbeat was
found at a later doctor's visit, and the Montalvos were referred to a
maternal fetal medicine specialist, Dr. Brian Kirshon.
"We couldn't have been
more surprised when Dr. Kirshon told us we were having four babies and
that they were two sets of twins," Manuel Montalvo said.
Each pair of twins shared a placenta, the hospital said.
Identical twins result
when a fertilized egg splits into two embryos. Twins occur in about 2%
of all pregnancies, according to the University of Pennsylvania Health System. Of those, 30% are identical twins.
The odds of having two
sets of twins at once is about 1 in 70 million, said Dr. Alan Penzias,
associate professor of obstetrics, gynecology and reproductive biology
at Harvard Medical School.
The boys were all born
at 31 weeks' gestation, so they face some health risks, as their immune
systems aren't fully developed, said Krista Cato, a nurse in the
pediatric intensive care unit of Children's National Medical Center in
Washington.
Manuel Montalvo said he and his wife were trying to have "one little brother or sister" for their 2-year-old son, Memphis.
"We didn't expect it,"
Tressa Montalvo said. "We were trying for just one and we were blessed
with four. ... We planned the pregnancy -- I guess we just succeeded a
little too much."
Still, the Montalvos say, they are planning on trying again. "We want a girl," Manuel Montalvo said.
