A global study that gathered the rate of multiple births from 165 countries revealed an all-time high with at least half a million more twins born every year since 2010. The increase is mostly from continents where medically assisted reproduction (MAR) techniques were last introduced after the year 2000 - South Asia and Africa. But scientists believe the world has reached its peak twins rate, which is now expected to go downhill moving forward.
How the World Achieved Peak Twins Rate
Researchers studied data covering 99 percent of the human population, comparing data between 1980 to 1985 and 2010 to 2015. The rate of multiple births has increased by over 30 percent, from 9 to 12 twins birthed per 1,000 deliveries.
Several factors may have contributed to the rise in twin births which include contraception use and lower overall fertility. There has also been a trend among women who delay childbearing. With an increase in the mother's age, it is also believed that there is also an increase in the likelihood of multiple births. Hence, the longer a couple waits to get pregnant, the probability of conceiving twins shoots up, Vice World News reported.
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Genetics Play Significant Role in Escalating Twins Rate
More non-identical twins are born in Africa than elsewhere in the world. Africa, to date, has the highest rate of twins in the world. There are 17 twins birthed per every 1,000 deliveries in Africa, Live Science reported. However, the rate of multiple twins birthed in Africa remained throughout the three-decade period. Researchers suggest that Africa could be more genetically-prone to twin births than other populations in the world.
IVF and Other Medically Assisted Reproduction Techniques Cause Spike in Multiple Births Rate
Professor Christiaan Monden, one of the researchers of the global study from the University of Oxford in the U.K., noted that the main driving force which resulted in the peak twins rate is MAR or medically assisted reproduction techniques. MAR started gaining traction in the 1970s, including in vitro fertilization (IVF), ovarian stimulation, and artificial insemination. Now, there are about 1.6 million twins birthed every year. Such procedures like IVF increase the likelihood of conceiving twins as multiple fertilized embryos are implanted in the woman.
The Risks of Conceiving Twins
The researchers believe that the rate of conceiving twins has achieved its peak. High-income regions such as North America and Europe are now more focused on refining fertility treatments with the goal of minimizing multiple births. "This is important as deliveries of twins are linked to higher death rates, lower birth weights, premature babies, and other complications during pregnancy and post-delivery," Professor Monden noted.
The researchers further observed a huge difference in survival chances of twins between high-income and middle-to-low-income countries. In sub-Saharan Africa, over 200,000 twins lose their co-twin within the first year of life, BBC reported.
Single births are thought to be safer. With that in mind, it is expected that fertility treatments will be tweaked to increase the chances of pregnancy without necessarily bearing multiple babies at once.
