The United States is producing more twins. In fact, the rate in which they're born is the highest so far since 1980.
In a new maternal and fertility rate report released by the Centers for Disease Control and Prevention (CDC), the rate of twin birth has climbed to 33.9 twins per 1,000 live births in 2014. Although it's not too far from the 33.7 twins per live births the previous year, it's still considered as a record high.
The twin rate went up significantly over a period of a decade since 1980 with an increase of over 70%. Then it climbed very gradually at 2% from 2012 to 2013.
In 2014, at least 135,000 infants were born with twins, although the number is still lower than that of 1980 to 1998. Twins also have a lower birth weight at 9.56% compared to singletons, which have 1.07% low birth weight.
The report suggested that the increase of twin birth delivery is because of fertility treatments such as assisted reproductive technologies (ART). Almost 2% of all live births in 2012 were conceived through ART.
Further, in a 2013 data report by the CDC on ART, almost 200,000 ART cycles were carried out across 467 clinics around the country, a part of which included banking, a process in which either the sperm or the egg is harvested and frozen for future use. In the 2015 report, birth rates increased for women in their late twenties to early forties, which may imply they are delaying pregnancy.
While twin births increased slightly, other multiple births dropped substantially by as much as 5% in 2014. This means that live births within this category are already around 40% less than what the rate was in 1998. The report also linked the decrease to ART, but this time it referred to "changes in procedure."
Overall, more children were born in 2014 than in 2013, although two states, Colorado and Connecticut, experienced 50% or more decline.
