There Are Two Reasons Why Twin Births Are at a Historic High

Double the snuggles, double the cuteness, but double the diaper duty. Having twins is more common than ever, and a group of researchers think they know why we’re seeing a historic rise in twin births.

According to a new study, one in every 42 children born is now a twin, and that’s an increase by a third compared to the 1980s. This means that about 1.6 million twins are born every year worldwide! Researchers analyzed birth records from over 165 countries, but they think that instead of the number of twins increasing worldwide, we may have hit “twin peaks.”

“The trends are really quite striking,” said Christiaan Monden, a professor of sociology and demography at Oxford University. “Over the past 40 to 50 years we’ve seen a strong increase in twinning rates in rich, developed countries, and that has led to more twins in both a relative and an absolute sense than we’ve seen ever before.”

So, why do researchers feel there are so many twins being born? They say there are two factors at play that have led to the peak in twins.

First is the rise in parents using fertility treatments like in vitro fertilization (IVF) or ovarian stimulation, which both increase a woman’s odds of having twins. However, with new medical advancements, doctors are finding ways of improving their patients' success rates of giving birth without having multiple babies. These fertility treatments helped the rise of twins, but the newest practices could lead to less twins in the future and a downward trend of those numbers.

The second contributing factor is that many couples are waiting until they are older to have children. Several studies have shown that women between the ages of 35 and 39 have an increased chance of giving birth to multiples naturally.

For many parents, welcoming twins is an exciting and wonderful surprise, but researchers from the study note that twin pregnancies can come with complications—especially for women without proper health care. For low-socioeconomic nations, having twins means both the mother and her babies are at serious risk during and after the pregnancy.

Researchers hope that continued advancements in prenatal care and improved health care worldwide will lower these risks for mothers and twins.