Pregnancy is now a dream within reach for those who have trouble with conception thanks to advances in assisted reproduction. But as recent reports have shown, doctors are facing a catch-22 when it comes too many moms birthing two babies at once.
Reproductive Endocrinologist Dr. Jennifer Phy said a woman's chances of spontaneously birthing twins is about one in 100. That is, without modern reproductive medicine. According to the CDC
, the number of twins doubled in 2009 compared to 1980.
"Anytime you're increasing a couple's chance of conceiving, you're probably increasing a couple's chance for multiple births because that's sort of how the treatment works," Phy said.
Fertility drugs can increase a woman's chance of multiple births, usually twins, to one in 10, she said. And with In Vitro Fertilization, the chances are higher.
"The risk could be 50 percent."
Many factors are considered before a couple reaches this step.
"Sometimes, patients have diagnoses that will not permit them to become pregnant without more sophisticated treatments. So if there's a problem with a gentleman's sperm count, or if a woman's fallopian tubes are closed or not functional, then that family may be immediately committed to In Vitro Fertilization."
With IVF, a woman is given medication to help make eggs. Most physicians will obtain 10 to 15 eggs and fertilize them, Phy said.
"And a certain percentage will fertilize and begin developing in the laboratory. And then you may result in just a few embryos that are healthy and available to that couple to transfer to the mom's uterus, in hopes of having a baby."
Typically doctors will transfer two seemingly healthy embryos, in hopes that a least one succeeds.
"I think with physicians who are helping people to conceive, one healthy baby is always the goal. We want it to work because the patients are investing everything. Their time, and their emotions, and discomfort from shots, and life savings. So many times with In Vitro, you'll transfer the two best embryos."
Because IVF can cost anywhere from $7,000 to $25,000, many families welcome the idea of twins. But they can pose several risks.
"The greatest risk is pre-term delivery. So if a baby is born too early, it may not have proper eye development or lung development. There may be a prolonged hospitalization in the neonatal intensive care unit."
Dr. Phy said another option for families wanting a single embryo (to avoid the risks associated with twins) is genetic testing of the embryos.
"And now there are advances, there are scientific techniques that can be performed where you can screen and embryo and know if it's genetically normal or not."
Because some oppose these screenings on ethical grounds, Phy said she feels many couples will still opt for a multiple embryo transfer, despite the so called "twin epidemic." Fortunately, more twins means doctors and hospitals are getting even better at caring for them.