The U.S. twinning rate hit a record last year, with 33.9 out of every 1,000 births involving twins. Though the increase from the 2013 rate of 33.7 per 1,000 births isn’t big enough to be statistically significant, 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.
According to statistics, mothers continued to get older in 2014. The average age for a first-time mother is now 26.3, up from an even 26 in 2013. The teen birth rate is dropping sharply (9 percent in 2014 alone, with some states seeing decreases higher than 50 percent since 2007) due to better efforts to educate teens and provide them with long-term birth control like intrauterine devices.
Births for women in the first few years of their 20s are on a slower, however still steady, decline. On the other hand, the birth rate for women in their 30s, 40s and even 50s has increased over the years to a great extent.
Officials have reported that a rise in twin births is higher among older moms because the bodies of aged women tend to produce higher quantities of hormones, which 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 as compared to when she is in her 20s.
“The twin birth rate was 33.9 per 1,000 in 2014, which was not significantly higher than the rate for 2013 (33.7), but was a new high for the nation,” the report from the U.S. Centers for Disease Control and Prevention said. However, from 18.9 twins per 1,000 births in 1980, the “twinning rate” has nearly doubled over the past 36 years, the report pointed out.
Researchers have attributed the rise in twin birthrates to two possible factors: more women are using fertility treatments, such as in vitro fertilization, and more women are having children at an older age, Live Science reported.
Kimberlee McKay, who works as an OB/GYN with Avera Medical Group Obstetrics and Gynecology and is an identical twin, has seen the complications of having twins firsthand.
“My mom didn’t know she was having twins until about the month before they delivered, that’s been a wonder to me, because monozygotic twins (twins formed when one fertilized embryo splits) can have lots and lots of problems,” McKay said. “I have to fulfill my purpose because I see so many complications occur from twins.”
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 U.K. has a twin. The rate for IVF conception is much higher, i.e. one in four births is of twins or triplets.
Regardless of how a mother becomes pregnant, there are a number of risks associated with twins and multiples pregnancies, including gestational diabetes, high blood pressure for mothers, and prematurity and low birth weight for babies.