A Massachusetts middle school recently celebrated its eighth-grade “moving up” ceremony for its outgoing students, including a remarkable 23 sets of twins. 

Pollard Middle School, in Needham, Massachusetts, has a fairly large student body, Principal Tamantha Bibbo told the Associated Press (AP). But the sheer number of twins in this year’s eighth-grade class is “quite unusual,” she said. 

“We typically have anywhere from five to 10 sets at most,” Bibbo told the AP. “Given our numbers, we have approximately 450 to 500 children in each grade, so this was extraordinarily high.”

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The 23 sets of twins, plus another eighth-grade student whose twin brother attends a different middle school, comprise about 10% of the class, she said. 

They received a special mention during their “moving up” ceremony on Wednesday, June 12, Bibbo told the Associated Press. 

Twins represent about 3% of live births in the United States, according to the National Center for Health Statistics, meaning that the number of twins in Pollard Middle School’s eighth-grade class is more than three times what could be expected. 

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It was not clear what percentage of the twins at Pollard Middle School were identical or fraternal. 

How common are twins?

About one third of all twins are identical, meaning they were a single zygote that split in the womb, according to the U.K.’s National Health Service website. 

The other two-thirds of twins are fraternal, meaning they were two separate zygotes — and no more alike than any other siblings. 

The occurrence of fraternal twins can be linked to genetic factors, whereas the chance of identical twins is equal for every pregnancy, the National Health Service said. 

The number of twin (and other multiple) births in the United States increased steadily for three decades before beginning a gradual decline in 2019, according to the website for the Centers for Disease Control and Prevention (CDC).

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Twins are by far the most common multiple birth. In 2022, 114,483 twin births were recorded in the U.S., according to the CDC.

That same year, according to the CDC, there were 2,774 sets of triplets born in the U.S. and an additional 121 “quadruplet and other higher order births.” 

The reasons behind the increasing number of multiple births were not entirely clear and could be linked to many factors, including maternal age and the use of fertility treatments, the CDC said. 

A woman from Mali currently holds the world record for “most children delivered at a single birth to survive.” 

Halima Cissé delivered nine babies – nontuplets – on May 4, 2021, at a clinic in Casablanca, Morocco, the Guinness World Records reported on its website. 

The previous record was held by “octomom” Natalie Suleman, who delivered octuplets on Jan. 26, 2009. 

All nine of Cissé’s babies survived, and the family returned to Mali more than a year-and-a-half after their births, the Guinness World Records reported. 

The nontuplets were a surprise even to Cissé. 

Doctors in Mali originally thought she was carrying “only” seven babies, the Guinness World Records said. 

It was only when she was transferred to a clinic for specialized care in Morocco, the Guinness World Records reported, that doctors realized she was pregnant with nine.

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The nontuplets were delivered by cesarean section at 30 weeks gestation, and each weighed between 1.1 and 2.2 pounds at birth, the clinic’s director said, according to the Guinness World Records report. 

The Associated Press contributed reporting.