 |
| courtesy: https://sickbayby.wordpress.com/tag/multiple-gestation/ |
In order to promote
singleton pregnancies and bring down the number of multiple pregnancies in patients undergoing IVF,
American Society for Reproductive Medicine (ASRM) and Society for Assisted
Reproductive Technology (SART) updated the guidelines regarding the upper limit
number of embryos transferred in IVF cycle. These guidelines replace the previous
guidance issued in 2013.
The
incidence of triplets and higher order multiple births have essentially declined
in US for the last 15 years after steadily rising fourfold during the 1980s and
1990s. But, still multiple births are not desirable outcome of ART therapy.
The rise was
due to older maternal age and increased use of ARTs, with no guidelines on the
number of embryos transferred.
Triplets and
Higher order births continue to have poor prognosis with 7% succumbing in first
year of life as compared to .5% of singleton pregnancies. The ideal outcome
after an ART procedure is to have a singleton pregnancy.
National data from CDC in 2013 demonstrate that clinics that perform higher rates of elective
single-embryo transfer (eSET) in women aged <38 years have decreased rates
of multiple gestation, with no significant impact on cumulative live-birth
rates.
In women who
are 42 years or younger transferring a single euploid blastocyst resulted in
pregnancy rates similar to transferring two untested blastocysts while
dramatically reducing the risk of twins.
Patient has
the choice to choose the number of embryos transferred but it should be a fully
informed decision taking into consideration medical, ethical and financial
aspects of the procedure.
For drafting
the recommendations, the patients have been categorized into favorable prognosis
group and all others.
Conditions
associated with favorable outcome are young age: euploid embryos, one or more
good quality embryo available for cryopreservation and previous history of
livebirth after an ART cycle.
For frozen
embryo transfer the favorable conditions are when high quality, vitrified, day
5 or 6 blastocysts available.
The number
of embryo transferred should be agreed upon by the treating physician and
patients, depending upon the patient characteristics, data for the individual
procedure and data from the ART services provided by the clinic. The following
guidelines recommend the upper limits of the number of embryo transferred.
Patient with
favorable prognosis:
A single
euploid embryo transferred in patient of any age has the most favorable
prognosis.
Patients
under the age of 35 are always encouraged to receive one single embryo,
irrespective of the embryo stage.
Similarly,
for patients between 35-37 years of age, a single embryo transfer is
encouraged.
Patient
between 38-40years of age, a single euploid embryo should be transferred, if
availability is restricted than three cleavage-stage embryos or two blastocysts
should be transferred.
Similarly,
for patients between 41-42 years of age, the choice is to transfer single
euploid embryo, if not than four cleavage-stage embryos or three blastocysts is
the second choice.
Other
scenarios:
In each of
the above age group, if the patients do not belong to favorable prognosis
category they can receive an additional embryo based on individual circumstances.
If patients
who are in favorable prognosis category but fail to conceive after repeated
cycles than an additional embryo may be transferred. If these patients have
some coexisting medical condition that put them at high risk because of multiple
gestation, a single embryo transfer is recommended.
In cases
where the number of blastocysts transfer exceed the recommended limit, patient should
receive counselling and everything should be well documented on the medical
record.
Patients who
are more than 43 years of age, insufficient data exist for number of embryos to
be transferred using her own oocytes. The risk of multiple pregnancy increases
dramatically as age increases, so caution must be exercised.
In
donor-oocyte cycles decision should be made according to donor's age.
In frozen embryo
transfer cycles, the patient should be categorized into favorable/other scenarios group according to age of women when the embryo was frozen. And the number of frozen
embryo transferred should not exceed the number of fresh embryo transfer recommended
for each age group.
The full article in the Journal of Fertility and Sterility can be accessed here.
