Mar 12, 2021 07:35 AM
https://www.theguardian.com/science/2021...y-services
EXCERPTS: Twins may be more common today than at any time in history, according to the first comprehensive survey of twin births around the world. Researchers analysed records from more than 100 countries and found a substantial rise in twin birthrates since the 1980s, with one in 42 people now born a twin, equivalent to 1.6 million children a year. According to the study, the global twin birthrate has risen by one-third, on average, over the past 40 years. Rather than seeing the trend continue, the world may have reached “peak twin”, the authors say, as the most recent data suggest some countries have begun to see twinning rates plateau or even fall from historic highs.
[...] Twins are born naturally when a fertilised egg spontaneously splits in half, leading to identical twins, or when the mother releases two eggs at once that are both fertilised, producing non-identical twins. Most now are born as a result of fertility treatments, such as ovarian stimulation or having more than one in vitro fertilisation (IVF) embryo transferred into the womb at the same time, a practice now discouraged in many countries on health grounds.
While the birthrate for identical twins has barely changed over time, Monden and his colleagues found that naturally conceived, non-identical twins and twins born as a result of medically assisted reproduction – an umbrella term for a range of fertility treatments – had risen globally.
[...] “The absolute number of twin deliveries has increased everywhere except South America,” Monden said. “In North America and Africa, the numbers have increased by more than 80%, and in Africa this increase is caused almost entirely by population growth.” (MORE - details)
EXCERPTS: Twins may be more common today than at any time in history, according to the first comprehensive survey of twin births around the world. Researchers analysed records from more than 100 countries and found a substantial rise in twin birthrates since the 1980s, with one in 42 people now born a twin, equivalent to 1.6 million children a year. According to the study, the global twin birthrate has risen by one-third, on average, over the past 40 years. Rather than seeing the trend continue, the world may have reached “peak twin”, the authors say, as the most recent data suggest some countries have begun to see twinning rates plateau or even fall from historic highs.
[...] Twins are born naturally when a fertilised egg spontaneously splits in half, leading to identical twins, or when the mother releases two eggs at once that are both fertilised, producing non-identical twins. Most now are born as a result of fertility treatments, such as ovarian stimulation or having more than one in vitro fertilisation (IVF) embryo transferred into the womb at the same time, a practice now discouraged in many countries on health grounds.
While the birthrate for identical twins has barely changed over time, Monden and his colleagues found that naturally conceived, non-identical twins and twins born as a result of medically assisted reproduction – an umbrella term for a range of fertility treatments – had risen globally.
[...] “The absolute number of twin deliveries has increased everywhere except South America,” Monden said. “In North America and Africa, the numbers have increased by more than 80%, and in Africa this increase is caused almost entirely by population growth.” (MORE - details)