Tressa Montalvo loved growing up in a family with six siblings, but she never expected her own to become so big, so fast.
The 36-year-old Houston native beat what the Woman's Hospital of Texas calls 1-in-70-million odds to naturally give birth to a rare form of quadruplets: two sets of identical twins.
Unlike quadruplets who split from one egg and grow in one placenta, these four boys grew in pairs within two placentas for 31 weeks before Tressa had a complication-free Caesarean section on Valentine's Day.
The arrival of Ace and Blaine, then Cash and Dylan a minute later, was even more unusual because the Montalvos did not take fertility drugs or use in-vitro fertilization, which have contributed to a 76 percent increase in multiple births nationwide between 1980 and 2009, according to the Centers for Disease Control and Prevention.
Tressa and her husband, Manuel, 43, were surprised to learn 10 weeks into her pregnancy that she'd be having twins. Her physician heard a third heartbeat on her next visit and referred her to Dr. Brian Kirshon, a maternal fetal medicine specialist at the Woman's Hospital, who told the family to expect quadruplets.
"You're sitting there crying, and you're not sure why," Tressa said, remembering the day she heard the news. "It was just overwhelming."
With no serious health complications and birth weights between 2 pounds, 15 ounces and 3 pounds, 15 ounces, the boys, who will remain at the hospital another six weeks, have an excellent chance of leading normal, healthy lives, hospital officials said.
Manuel Montalvo said he still wants a girl but deferred the decision to his wife.