Economic News Network, Buenos Aires, Argentina
Around 1.6 million pairs of twins are born worldwide each year. This means that one in every 42 new births is twin. Since the 1980s, the proportion has increased from 9 pairs of twins per 1,000 births to 12 pairs. Notable mothers who gave birth to twins include Angelina Jolie, Julia Roberts, Beyoncé, Jennifer Lopez, Celine Dion and Maria Kelly.
One of the main reasons for this is the increase in the use of medically assisted reproduction. Medically assisted reproduction includes in vitro fertilization (IVF), ovarian stimulation, and artificial insemination. Delayed fertility (a trend that has emerged in many countries) is another factor. The probability of having twins increases with the mother's age. These are some of the conclusions of a new study published by experts at oxford university in the latest issue of the journal Human Reproduction.
Christian Mondon, an expert at the University of Oxford and lead author of the study, said: "The relative and absolute number of twins in the world is currently higher than since the mid-20th century and could be at an all-time high. "This is important because increased twins are associated with higher infant and child mortality rates and increased complications for mothers and babies during, during and after childbirth."
The study is the first comprehensive global analysis of its kind. It is based on twin birth rate data from 165 countries between 2010 and 2015, covering 99% of the world's population. The researchers compared the data with similar data from 112 countries between 1980 and 1985.
The United States, Europe and Asia saw increases of 71%, 61% and 32%, respectively. There has been significant growth across the European region. Three of the continent's four countries (about 74 percent) saw an increase of more than 10 percent. Only 7 countries experienced a decline of more than 10 per cent.
"During both periods, Africa had the highest twin birth rate and did not show a significant increase over time." Mondon explained. However, Countries in Europe, North America and Asia are catching up quickly. Today, about 80% of the world's twins are born in Asia and Africa. Due to the large number of fraternal twins (from two different eggs) born, the twin rate in Africa has reached such a high level. "This is most likely due to genetic differences between the African population and the population of other regions," Mondon said.