"Where you stand depends on where you sit."  These words could not be more true for couples undergoing in-vitro fertilization (IVF) treatments.  Some of these couples will have the opportunity to transfer one embryo (single embryo transfer, or SET) or two, in what becomes one of the most momentous decisions of their entire treatment.  For many, there will be a significant temptation to have two embryos implanted.  This is based on a desire to maximize the chances of at least one child, or to "get two pregnancies over with" at once.   But there is one person who will always be hoping for a single pregnancy:  the person who is going to be doing the actual delivery, the obstetrician.  

The vast majority of twin pregnancies via IVF conclude with healthy babies and a healthy mom.  But there are legitimate, increased risks.  The central risk of a twin pregnancy is of pre-term delivery.  Nearly 60% of twins deliver before term (term is 37 weeks), and 11 percent deliver before 32 weeks.  These early deliveries involve risks to the fetus such as respiratory distress, gastrointestinal infections and even intracranial bleeds and will require longer neonatal intensive-care unit (NICU) courses for the infants.  There is an increased risk of developmental delay even in deliveries between 32 and 36 weeks (8%, vs 4% at term). More substantial neuro-developmental risks are present at earlier gestational ages.

Twin pregnancies also carry a two-fold increased risk of pregnancy-induced hypertension and increased risk of growth restriction in one or both fetuses.   Twin pregnancies, eve after 20 weeks, have a 5% chance of loss of one of the twins prior to birth.  It also dramatically increases the chance cesarean section if the position of the fetuses in the uterus at delivery is not optimal.  Twin pregnancies require patients to consult with high risk OB doctors, called maternal fetal medicine physicians.   

It is important to note, for twin pregnancis that progresses to term, nearly 94% will continue to have a good outcome for both twins through infancy.  

The number of embryos to implant in an IVF cycle must always be done on a case-by-case basis.  There may be situations where the fertility doctor might actually advise for the transfer for more than one embryo.  Ultimately, an IVF cycle and embryo transfer must take into consideration the clinical situation unique to each couple.  

As a generalist obstetrician/gynecologist, I encourage couples that are deciding how many embryos to transfer to carefully consider the risks. Twin pregnancies usually progress very well, but every OB/GYN knows that singleton pregnancies will always carry a much lower complication rate.  

When I walk into the room to meet an IVF couple, and I see that there is one fetus, I know that this couple has the best chance for a smooth, uneventful pregnancy and a healthy baby at the end of of their long pregnancy journey.

In December, Dr. Allan Kessel participated in a radio program on WMTR 1250AM with Dr. Jamie Morris from Reproductive Medicine Associates (RMA) on the topic of fertility.  Single embryo transfer, as well as other issues were discussed.  A link to the program is below:  

http://answerslivenj.com/albums/pregnancy/