The CDC (Centers for Disease Control and Prevention) released a report showing that the rate of twin births has risen quite substantially since the 1980s, especially amongst older women.

In 1980, one in every 53 births was a twin birth, while by 2009 the number had risen to one in every 30, or three percent. The rise constitutes a 76 percent increase in twin births, from nearly 19 per thousand in 1980 to more than 33 per thousand by 2009. The rise can be seen across every state including DC, coming in at least fifty percent higher.

Older women are seeing higher rates still, with a two hundred percent increase in those over forty, while the rate of those 35-39 rose 100 percent. The older age of women giving birth by 2009 accounts for about one third of the rise in twinning.

What the report doesn’t make clear is the difference between genetically identical twins and fraternal twins. There is obviously a vast difference, since identical twins are a naturally occurring genetic anomaly, whereas fraternal twins are caused by two eggs being fertilized at the same time. Obviously, the use of fertility treatments has risen dramatically since the 1980s, ranging from basic hormone shots to stimulate the women to ovulate, through to complex IVF treatments where multiple zygotes (fertilized eggs) are deliberately implanted to insure survival of at least one embryo.

Studying the rate of identical twin births against fraternal births over the same period would have provided a clearer picture of how much the fertility programs are causing twin births to increase. Twin birth figures for 1915 come in at only two percent, relatively stable compared to the 1980 figure. Thus on face value, it would appear that medical science is largely responsible for the rapid increase of twin births over the last three decades.

It is important to understand and monitor the rate of twin births, because they are generally considered to be tougher on the mothers health, as incubating two fetuses instead of one takes its toll on her, and giving birth to twins more often leads to complications during birth or an elective cesarian section. Twinning also tends to cause more preterm births and lower birth weights, leading to possible health issues for twins later in life. In fact it’s quite common to find twin children where one appears very slightly less physically developed or ‘weaker’ than the other.

The CDC report shows that an additional 865,000 twin births occurred over the last three decades, and while the CDC does eventually make the conclusion in their report that the use of fertility treatments is most likely the cause, and makes note of the pressure this can put on both mothers, their children and the healthcare system at large, it mainly presents the dry data without attempting to delve further into the issue.

The report contains data from the Natality Data File from the National Vital Statistics System and the vital statistics natality file includes information on a wide range of maternal and infant demographic and health characteristics for all births occurring in the United States.

It’s useful information that perhaps ought to lead to a more in depth study into the fertility industry and its effect on mothers, children and the healthcare system. However, the report does also point out that women, in general, are getting pregnant later in life, which in itself does have a tendency to produce more twinning. In 1980, women over 30 accounted for only twenty percent of births, whereas today, they account for thirty five percent, an increase of 75% that almost perfectly matches the increase in the rate of twining. The figures are not as simple as that says the CDC which estimates that natural twin pregnancies in older women accounts for around one third of the increase, while the other two thirds is most likely from fertility programs.

It would be nice to see a more in depth study from a University that includes some statistics on women using fertility programs, and also uses rates of identical twins over the last few decades to compare with rates of fraternal ones. In 2009 Marketdata Enterprises, Inc. released a report showing that the fertility industry in the United States is worth some $4 Billion a year, so it’s no surprise that the CDC chooses to downplay the side effect of an extra 200,000 twin births per decade, that a profitable medical science appears to have created.

Written by Rupert Shepherd