The rate of twin births increased in recent decades, soaring by 76% from 1980 to 2011, according to the National Center for Health Statistics. Despite the near record high rate, twin births remain relatively rare, accounting for just 34 out of every 1,000 births in 2016.
There are two reasons for the rise in twin births. The first is that women are having babies at older ages, and the peak age for having twins is around 35. The second, more impactful, reason is that fertility treatments have become increasingly common, leading to multiple births.
The twin birth rate is different between states. 24/7 Wall St. reviewed government data and ranked states from the lowest to the highest birth rate of twins.
To identify the states where the most twins are are born, 24/7 Wall St. reviewed the Center for Disease Control and Prevention’s National Vital Statistics Reports. The twin birth rate is per every 1,000 live births. This rate, as well as the total number of twin births, were collected between 2014 and 2016. The data for total births in each state is for 2016. Fertility rates are calculated as births per 1,000 women aged 15–44 and are also for 2016. The rate of first births to older women aged 35 to 44 in each state came from the CDC and are for 2012, the latest period for which data is available.