More twins: 1 in 30 babies born in U.S. is a twin

In 2009, one in every 30 babies born in the United States was a twin. That’s compared with one baby in every 53 in 1980.

In 2009, one in every 30 babies born in the United States was a twin. That’s compared with one baby in every 53 in 1980. This marked increase in the birth of twins is happening because of the the growing availability of fertility treatments, and because women are having children at older ages, according to research presented the 14th Congress of the International Society of Twin Studies in Florence, Italy in April, 2012.

Photo credit: Lida Rose

Michigan State University’s Barbara Luke, a researcher in the College of Human Medicine’s Department of Obstetrics, Gynecology and Reproductive Biology, said the increase in twin births have important health implications, including greater morbidity and mortality risks and higher health care costs.

Luke said that twin births increased for women of all ages, with the largest increases among women aged 30 and older. She said:

Prior to 1980, the incidence of U.S. twin births was stable at about 2 percent of all births, but it has risen dramatically in the past three decades. Older maternal age accounts for about one-third of the rise, and two-thirds is due to the increased use of fertility treatments.

Those fertility-enhancing therapies include both assisted reproductive technologies and ovulation stimulation medications. About 12 percent of U.S. women have had fertility therapies. Luke said:

With multiple births though there are greater health risks. Continued research is necessary to improve outcomes.

Luke noted that births for triplets and higher numbers also grew: one in every 651 babies in 2009 compared with one in 2,702 in 1980.

Photo credit: cybaea

Previous findings have shown mothers using fertility treatments experience more adverse health outcomes than spontaneous-conception pregnancies. Luke and her team hypothesized the residual effects of fetal loss may impact the subsequent growth and birth weight of the surviving fetuses.

The 14th Congress of the International Society of Twin Studies is held from April 1-4. The conference brings together experts from across the world to study multiple pregnancies and better understand the health impacts, specially neurological and oncological.

Bottom line: According to research presented the 14th Congress of the International Society of Twin Studies in Florence, Italy in April, 2012, in 2009, one in every 30 babies born in the United States was a twin. That’s compared with one baby in every 53 in 1980. This marked increase in the birth of twins is happening because of the the growing availability of fertility treatments, and because women are having children at older ages, said the researchers.

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