381
Letters to the Editor
N. Gleicher*, V.A. Kushnir and D.H. Barad The Center for Human Reproduction – New York, 21 East 69th Street, New York, NY 10021, USA *Correspondence address. E-mail: [email protected] doi:10.1093/humrep/det444 Advanced Access publication on December 10, 2013
Legislation of embryo transfer affected the denominator, not the numerator! Sir, With interest we read the article of De Neubourg et al. (2013). The authors concluded that legislation of the number of embryos transferred decreased the number of multiple pregnancies for a stable pregnancy rate per cycle. We are afraid that their conclusions reflect the impact of the new policy on the cycle level, but not on the absolute number of multiple embryo transfers. Judgment of the effect of these measures on the population level puts the reported findings in a different light. As the policy change was made in 2003, let us consider the years 2002, 2004 and 2010 (Table I). The number of assisted reproductive technology (ART) cycles in those years increased from 11 254 (2002) to 14 237 (2004) and 19 110 cycles (2010). Although the rates of double and triple embryo transfers per cycle decreased in favor of single embryo transfer, this did not result in a comparable reduction of the absolute numbers of multiple embryo transfers; 9671 in 2002 versus 9555 in 2010 (after a slight decrease occurred in 2004). More importantly, the absolute numbers of multiple pregnancies from ART remained comparable from 447 in 2002 to 407 multiple pregnancies in 2010 (despite the triplet reduction from 18 to 7), thus denying the claim that cycle regulation and control reduced the number of multiple pregnancies. When we compare 2002 and 2010, the decrease in the transfer of multiple embryos per cycle was due to an absolute increase in the number of cycles and not by a decrease in the number of multiple embryo transfers. Interestingly, as the 2004 data show, the legislation initially reduced the absolute number of twins strongly for an increase of the
Table I Assisted reproductive technology cycles and deliveries before and after legislation. 2002
2004
2010
........................................................................................ Cycles (N)
11 245
14 237
19 110
SET
1687
6834
9937
DET
5285
5980
7644
TET
2474
1139
1529
.TET
1912
285
382
15
48
52
DET
47
42
40
TET
22
8
8
.TET
17
2
2
Cycles (%) SET
Deliveries (%) Singleton
75.0
90.1
88,8
Twin
24.0
8.7
11,2
Triplet
1.0
0.2
0,2
Deliveries
1788a
2196
3556
Singleton
1341
1992
3149
Twin
429
191
400
Triplet
18
5
7
Deliveries (N)
Percentage may add up to more than 100% due to rounding. DET, double embryo transfer; SET, single embryo transfer; TET, triple embryo transfer. a Andersen et al. (2006).
number of deliveries. However, the strong increase in the number of cycles thereafter nullified this effect. Unfortunately, the report provides no data on the number of cycles per couple, the number of couples being treated and the indications for treatment. When assessing the impact of assisted reproductive technology, the cycle perspective alone seems insufficient and a population report reflecting the per couple effect is warranted.
References Andersen AN, Gianaroli L, Felberbaum R, de MJ, Nygren KG. Assisted reproductive technology in Europe, 2002. Results generated from European registers by ESHRE. Hum Reprod 2006;21:1680 – 1697. De Neubourg D, Bogaerts K, Wyns C, Albert A, Camus M, Candeur M, Degueldre M, Delbaere A, Delvigne A, De Sutter P et al. The history of Belgian assisted reproduction technology cycle registration and control: a case study in reducing the incidence of multiple pregnancy. Hum Reprod 2013;28:2709 – 2719. I. Scholten*, E. Kamphuis and B.W.J. Mol Centre for Reproductive Medicine, Meibergdreef 9, 1105 AZ AMC Amsterdam, The Netherlands *Correspondence address. E-mail: [email protected] doi:10.1093/humrep/det415 Advanced Access publication on November 25, 2013
Downloaded from http://humrep.oxfordjournals.org/ by guest on November 13, 2015
Gleicher N, Barad DH. Mistaken advocacy against twin pregnancies following IVF. J Assist Reprod Genet 2013;30:575– 579. Sazonova A, Ka¨llen K, Thurin-Kjellberg A, Wennerholm UB, Bergh C. Neonatal and maternal outcomes comparing women undergoing two in vitro fertilization (IVF) singleton pregnancies and women undergoing one IVF twin pregnancy. Fertil Steril 2013;99:731 – 737. Scotland GS, McNamee P, Peddle VL, Bjattacharya S. Safety, versus success in elective single embryo transfer: women’s preferences for outcomes of in vitro fertilization. BJOG 2007;114:977 – 983. Sharara FI. Despite significant financial incentives many couples still decline elective single embryo transfers (eSET). Feril Steril 2013;100: S145. Society for Assisted Reproductive Technology. SART National Summary of IVF Success Rates. 2011, https://www.sartcorsonline.com/rptCSR_ PublicMultYear.aspx?ClinicPKID=2329 (5 November 2013, date last accessed). Stillman RJ, Richter KS, Jones HW Jr. Refuting a misguided campaign against the goal of single-embryo transfer and singleton birth in assisted reproduction. Hum Reprod 2013;28:2599 – 2607.
Letters to the Editor
N. Gleicher*, V.A. Kushnir and D.H. Barad The Center for Human Reproduction – New York, 21 East 69th Street, New York, NY 10021, USA *Correspondence address. E-mail: [email protected] doi:10.1093/humrep/det444 Advanced Access publication on December 10, 2013
Legislation of embryo transfer affected the denominator, not the numerator! Sir, With interest we read the article of De Neubourg et al. (2013). The authors concluded that legislation of the number of embryos transferred decreased the number of multiple pregnancies for a stable pregnancy rate per cycle. We are afraid that their conclusions reflect the impact of the new policy on the cycle level, but not on the absolute number of multiple embryo transfers. Judgment of the effect of these measures on the population level puts the reported findings in a different light. As the policy change was made in 2003, let us consider the years 2002, 2004 and 2010 (Table I). The number of assisted reproductive technology (ART) cycles in those years increased from 11 254 (2002) to 14 237 (2004) and 19 110 cycles (2010). Although the rates of double and triple embryo transfers per cycle decreased in favor of single embryo transfer, this did not result in a comparable reduction of the absolute numbers of multiple embryo transfers; 9671 in 2002 versus 9555 in 2010 (after a slight decrease occurred in 2004). More importantly, the absolute numbers of multiple pregnancies from ART remained comparable from 447 in 2002 to 407 multiple pregnancies in 2010 (despite the triplet reduction from 18 to 7), thus denying the claim that cycle regulation and control reduced the number of multiple pregnancies. When we compare 2002 and 2010, the decrease in the transfer of multiple embryos per cycle was due to an absolute increase in the number of cycles and not by a decrease in the number of multiple embryo transfers. Interestingly, as the 2004 data show, the legislation initially reduced the absolute number of twins strongly for an increase of the
Table I Assisted reproductive technology cycles and deliveries before and after legislation. 2002
2004
2010
........................................................................................ Cycles (N)
11 245
14 237
19 110
SET
1687
6834
9937
DET
5285
5980
7644
TET
2474
1139
1529
.TET
1912
285
382
15
48
52
DET
47
42
40
TET
22
8
8
.TET
17
2
2
Cycles (%) SET
Deliveries (%) Singleton
75.0
90.1
88,8
Twin
24.0
8.7
11,2
Triplet
1.0
0.2
0,2
Deliveries
1788a
2196
3556
Singleton
1341
1992
3149
Twin
429
191
400
Triplet
18
5
7
Deliveries (N)
Percentage may add up to more than 100% due to rounding. DET, double embryo transfer; SET, single embryo transfer; TET, triple embryo transfer. a Andersen et al. (2006).
number of deliveries. However, the strong increase in the number of cycles thereafter nullified this effect. Unfortunately, the report provides no data on the number of cycles per couple, the number of couples being treated and the indications for treatment. When assessing the impact of assisted reproductive technology, the cycle perspective alone seems insufficient and a population report reflecting the per couple effect is warranted.
References Andersen AN, Gianaroli L, Felberbaum R, de MJ, Nygren KG. Assisted reproductive technology in Europe, 2002. Results generated from European registers by ESHRE. Hum Reprod 2006;21:1680 – 1697. De Neubourg D, Bogaerts K, Wyns C, Albert A, Camus M, Candeur M, Degueldre M, Delbaere A, Delvigne A, De Sutter P et al. The history of Belgian assisted reproduction technology cycle registration and control: a case study in reducing the incidence of multiple pregnancy. Hum Reprod 2013;28:2709 – 2719. I. Scholten*, E. Kamphuis and B.W.J. Mol Centre for Reproductive Medicine, Meibergdreef 9, 1105 AZ AMC Amsterdam, The Netherlands *Correspondence address. E-mail: [email protected] doi:10.1093/humrep/det415 Advanced Access publication on November 25, 2013
Downloaded from http://humrep.oxfordjournals.org/ by guest on November 13, 2015
Gleicher N, Barad DH. Mistaken advocacy against twin pregnancies following IVF. J Assist Reprod Genet 2013;30:575– 579. Sazonova A, Ka¨llen K, Thurin-Kjellberg A, Wennerholm UB, Bergh C. Neonatal and maternal outcomes comparing women undergoing two in vitro fertilization (IVF) singleton pregnancies and women undergoing one IVF twin pregnancy. Fertil Steril 2013;99:731 – 737. Scotland GS, McNamee P, Peddle VL, Bjattacharya S. Safety, versus success in elective single embryo transfer: women’s preferences for outcomes of in vitro fertilization. BJOG 2007;114:977 – 983. Sharara FI. Despite significant financial incentives many couples still decline elective single embryo transfers (eSET). Feril Steril 2013;100: S145. Society for Assisted Reproductive Technology. SART National Summary of IVF Success Rates. 2011, https://www.sartcorsonline.com/rptCSR_ PublicMultYear.aspx?ClinicPKID=2329 (5 November 2013, date last accessed). Stillman RJ, Richter KS, Jones HW Jr. Refuting a misguided campaign against the goal of single-embryo transfer and singleton birth in assisted reproduction. Hum Reprod 2013;28:2599 – 2607.
