As per a new 2014 report released by the US Centers for Disease Control and Prevention (CDC), twinning rate has hit all time high in the United States in 2014. In 2014, the birth rate for twins was 33.9 sets of twins per 1,000 births compared to 33.7 in 2013. It has been reported that mothers continued to get older in 2014 with the average age for the first-time mother has now become 26.3, which it was 26 in 2013. According to a report from the National Center for Health Statistics, out of all the twins recorded 78,788 were born to white women, 23,546 were born to black women and 22,051 were born to Latinas.
In 2104, about 135,336 twins were born in the U.S, which was 2% higher compared to it was in 2013, but nearly 3% lower than the all-time high of 138,961 twin births, set in 2007. The reason for so much increase in twin birth rates might be due to the fact that American women are waiting longer to get pregnant. It might be the fact that aged women tend to produce higher quantities of hormone that triggers the maturation of an egg-producing follicle. It further means a woman is more likely to have two eggs available for fertilization during a single cycle in her 30s than she is during her 20s. Though, it is not always that women in later age will have fraternal twins as older eggs are more likely to be unviable, a significant portion of them can be expected to have fraternal twins.
Another reason for the increase in twin birth rate could be the success of In-Vitro fertilization. The Society for Assisted Reproduction Technology advises many patients with a good prognosis for a successful pregnancy to transfer no more than two embryos at a time. Since 1980s, about 79% increase in twin birth rates have been reported till now with the birth rate for triplets and higher-order multiples has declined 41% since peaking in 1998. In 2014, 113.5 out of every 100,000 births involved higher-order multiples, the lowest it has been in 20 years.
According to a report from the LA Times, The U.S. twinning rate hit a record last year, with 33.9 out of every 1,000 births involving twins. That increase from the 2013 rate of 33.7 per 1,000 births isn’t big enough to be statistically significant, but it did qualify as “a new high for the nation,” according to a report from the National Center for Health Statistics.
Among all of those twins, 78,788 were born to white women, 23,546 were born to black women and 22,051 were born to Latinas.
Well, it's actually a pretty simple reason: IVF. More and more women are waiting to have children into their 30s and 40s, which means that more and more women are turning to in vitro fertilization for assistance. The way IVF works is that your fertility doctor implants as many embryos as possible in order to increase the chances of having a viable embryo. But IVF is a pretty solid practice and so it's working — better than some people anticipated. Woman are finding that two or three embryos are viable, resulting in twins and triplets, or in Kate Gosselin's case, twins and sextuplets, told the Bustle.
The MotherJones notes that, This comes from the CDC's final report on births for 2014, which is chock full of everything you might want to know about US birth and fertility rates. The increase in triplet births is most likely due to the rising use of fertility therapies, and the drop after 1998 is likely due to improvements in fertility therapies. The reason for the steady increase in twins is less clear, since it seems too large to be accounted for by fertility treatments.
Interestingly, blacks have the highest twin rate and Hispanics have the lowest. For triplets, whites have the highest rate—probably because the triplet rate is influenced by expensive fertility treatments, which whites are more able to afford than others.