Twins: Double the Fun or Double the Risk?

Twins

Fertility doctors say there is a new epidemic developing:  more mothers than ever are giving birth to twins.  In fact, government statistics show that almost half of all births that occur with the assistance of fertility treatments are now multiples.

For many, the case of “Octomom” was a cautionary tale about the consequences of implanting too many embryos at one time, and cases of big multiple births have gone down.  The rate of twin births, however, has not changed.

The reason that twin births have not gone down may be because people do not perceive twins as being particularly risky, compared with giving birth to large numbers of babies.  However, experts say, that even having two babies at once can create higher risk for the babies.  Twins have a greater risk for being born prematurely and having serious health concerns as a result.

Because of these added risks, fertility doctors are now encouraging their patients to implant only one embryo at a time.  While patients may have concerns about using this method, feeling that if they are going to go through the expense and trouble of having fertility treatments that they should increase their odds of conceiving as much as possible, doctors say this is not as necessary as it once was.  Modern methods allow doctors to evaluate embryos and choose which one has the best chances of implanting and developing into a healthy baby.

And, it does appear that more and more fertility patients are buying into this approach.  New parents Ken and Abigail Ernst from Oldwick, N.J. say they opted to use only one embryo in order to conceive their daughter Lucy.  It “just seemed the most normal, the most natural way,” says Abigail.

Of course, there are also parents who will specifically request that they want to have twins, according Barbara Collura, president of an infertility support group called Resolve.  While in theory it sounds like two babies would be better than one, Collura says, the reality is that there are increased risks for both mother and baby.

According to the Center for Disease Control and Prevention (CDC), about 37 percent of multiples are born prematurely, compared to only about 12 percent of singletons who are born earlier than their due date.  Despite this added risk for preterm birth, about 46 percent of babies conceived through IVF are multiples.  Only about three percent of babies conceived without medical assistance are multiples.

Although twin births due to fertility treatments are very common in the United States, other countries around the world do not seem to have this problem.  In fact, many European countries, which tend to cover the cost of treatment, have rules stating that only one embryo can be implanted per cycle of treatment.

The American Society of Reproductive Medicine would like to see a similar rule go into effect in the U.S.  Currently, its guidelines suggest that women under the age of 35 should be offered only a single embryo transfer, and never more than two should be transferred at one time.  These recommendations do rise in number as women age, however, to make up for the fact that older women have a much harder time becoming pregnant.  The guidelines also suggest that women should be educated about the risks associated with multiple births.

It does appear that more and more people are heeding their doctor’s advice.  Only four percent of women under the age of 35 used single embryos in 2007, but the figure had jumped up to 12 percent in 2011.  And, while the idea has been slower to gain acceptance among older women, they also account far fewer IVF pregnancies.

Dr. Richard T. Scott, Jr.,  the scientific director for Reproductive Medicine Associates of New Jersey, says the problem really isn’t that people want to have multiple babies.  They do, however, want to increase their chances of giving birth.  In the past, transferring more embryos was the best way to increase a patient’s chances of success.  However, doctors now have improved ways of screening embryos in order to select the best one for transfer.  They can allow embryos to mature a few days more, increasing their viability and allowing for chromosome screening.  In addition, embryos can be frozen to allow time for testing and more precise transfer times.

All in all, taking these steps will give better results, experts contend.  There will be fewer miscarriages and tubal pregnancies and healthier babies, they say.

And, the are studies which back up this contention.  Just this pay May a study was conducted in which 175 women were randomly assigned to have either a single embryo transfer after chromosomal screening or two embryos with no screening.  In both cases, delivery rates were virtually identical.  There were some differences, however.  First of all, about half of those who received two embryos went on to deliver twins.  Also, the babies from the double transfers were more likely to be born pre-term and spend time in intensive care.

While chromosomal testing and freezing does add more expensive to IVF – about $4,000 more – the pregnancy rates also go up dramatically, according to Scott.  In the long run, this saves money because patients don’t need to go through so many attempts.

By Nancy Schimelpfening

Sources:

Fertility Doctors Aim to Lower Rate of Twin Births – USA Today

Three Decades of Twin Births in the United States, 1980–2009 – CDC

Fertility Drugs and the Risk of Multiple Births – ASRM

 

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