According to a CDC report there has been a record number of twin births during the last year.
The rate of twin births in the United States reached 33.9 in every 1,000 births, up with two points compared to the previous year.
However, the report published on December 23 on CDC’s website shows that the number of twin births has doubled since the 1980s when out of 1,000 births only 18.9 were twins.
On the other side the rate of triplets and higher births have declined to 113.5 per 100,000 births in 2014 from 119.5 per 100,000 births in 2013. These births reached a new low last year, with a decrease of 40 percent from 1998 when it peaked, reaching 193.5 per 100,000 births.
According to the researchers more women are giving birth to twins as a result of two possible factors: fertility treatments such as IVF and the older age. Other studies have shown that women giving birth at an older age have an increased chance of having twins.
Each of these two factors has suffered major changes during the past years. Fertility treatments are now implanting only two or three embryos, compared to its early days when the number was much larger so women using the treatment were having even six or eight children.
Also, the rates of young women giving birth in their early 20s reached a new low in 2014 while those choosing to have children in their late 20s, 30s and even 40s reached a new high.
However, the United States is not alone in this. Studies from the United Kingdom also show an increased rate of twins births. One in 62 babies born in the UK has a twin. The rate for IVF conception is much higher – one in four births is of twins or triplets.
According to British scientists, there are more factors which could influence the birth of twins. One of them is having twins in the family. Then, it seems that Black people, especially West African descends are more likely to have twins.
The parent’s size could also matter, as people over 5.6 foot tall and with a body mass index of over 30 have more chances of having twins.
But the mother’s age seems to matter the most and women over 35 have increased chances of giving birth to twins. This is a result of the fact that as the woman gets older her body produces more ovulation-simulating hormones so her ovaries might release more eggs in one month.
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