Obstetrics & Gynecology Email Alerts
HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS
QUICK SEARCH:   [advanced]


     

Obstetrics & Gynecology 2004;104:102-109
© 2004 by The American College of Obstetricians and Gynecologists
This Article
Right arrow Abstract Freely available
Right arrow Full Text (PDF)
Right arrow Alert me when this article is cited
Right arrow Alert me if a correction is posted
Services
Right arrow Similar articles in this journal
Right arrow Similar articles in PubMed
Right arrow Alert me to new issues of the journal
Right arrow Download to citation manager
Citing Articles
Right arrow Citing Articles via HighWire
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Evans, M. I.
Right arrow Articles by Fletcher, J. C.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Evans, M. I.
Right arrow Articles by Fletcher, J. C.
Related Collections
Right arrow Ethics
Right arrow Genetics and teratology
Right arrow Prenatal Diagnosis
Right arrow Abortion

ORIGINAL RESEARCH

Fetal Reduction From Twins to a Singleton

A Reasonable Consideration?

Mark I. Evans, MD, Marion I. Kaufman, RN, Anita J. Urban, RDMS, David W. Britt, PhD and John C. Fletcher, PhD

From the Departments of Obstetrics & Gynecology, St. Luke's Roosevelt Hospital Center, Columbia University, New York; Drexel University College of Medicine, Philadelphia, Pennsylvania; and University of Virginia School of Medicine, Charlottesville, Virginia.

Address reprint requests to: Mark I. Evans, MD, Director, Institute for Genetics and Fetal Medicine, Suite 11A-11, 1000 10th Avenue, New York, NY 10019; e-mail: IGFM{at}chpnet.org.


   ABSTRACT
TOP
ABSTRACT
MATERIALS AND METHODS
 RESULTS
 DISCUSSION
 REFERENCES
 
OBJECTIVE: In the past, our group took the position that we would not provide multifetal pregnancy reduction to a singleton regardless of starting number except for serious maternal medical indications or as a selective termination for diagnosed fetal anomalies. With evidence of increased safety and more women (many aged 40 years or more) asking for counseling about reduction to a singleton, we reviewed our prior reasoning.

METHODS: We compared outcomes of 52 first-trimester twin-to-singleton for multifetal pregnancy reduction cases performed by a single operator to twin and singleton data from recent national register studies.

RESULTS: Twin-to-singleton reductions represent less than 3% of all cases. Forty of 52 patients were aged 35 years or more, 19 were aged more than 40 years, and 2 were aged more than 50 years (age range 32–54 years). Since 1999, 23 of 28 had chorionic villus sampling before multifetal pregnancy reduction. Fifty-one of 52 reached viability with mean gestational age at delivery of 37.2 weeks. One of 52 patients miscarried (1.9%). Compared with multiple sources of data for twins, the loss rate is lower in twins reduced to a singleton.

CONCLUSION: Until recently, multifetal pregnancy reductions to a singleton were rare. Physicians were concerned about the unknown risks of multifetal pregnancy reduction in this situation. They also had moral doubts about the justification to go "below twins." However, physicians know that spontaneous twin pregnancy losses average 8–10%. Also, with experience, multifetal pregnancy reduction has become very safe in our hands. Our data suggest that the likelihood of taking home a baby is higher after reduction than remaining with twins. We propose that twin-to-singleton reductions might be considered with appropriate constraints and safeguards.

LEVEL OF EVIDENCE: III

Multifetal pregnancy reduction has emerged as a morally controversial solution to the sequelae of aggressive attempts to treat infertility.1–4 Multifetal pregnancy reduction "treats" a symptom of a deep-seated set of biological, social, and economic problems. It ought to be understood as an interim approach before the advent of improved practices in infertility treatment and more scientific understanding of biological events at fertilization. Fertility treatments have allowed millions of women who could not otherwise conceive to have wanted children. However, the incidence of multiple pregnancies has reached epidemic proportions. Twins have increased to more than 250% of the natural incidence. The escalating number of multiples creates inequities in access to neonatal intensive care, family resources, and distribution of health care resources for other sick children (Table 1). 5–7 Some assisted reproduction technologies (ARTs), such as intracytoplasmic sperm injection, have been implicated with adverse fetal outcomes.8,9


View this table:
[in this window]
[in a new window]
  		Table 1. Multiple Births in the United States

 

Our prior publications raised technical, ethical, and psychosocial concerns about the proper use of multifetal pregnancy reduction and the context for offering the procedure.2,4 Some opponents of abortion argued multifetal pregnancy reduction was morally wrong, regardless of the number or condition of fetuses. In the 1980s and 1990s essentially, no one believed that multifetal pregnancy reduction could routinely be justified for twins to a singleton except in extremis, and the general debate was with the management of triplets.1–4

The public and professional positions were generally that twins did "well enough." However, closer inspection reveals that the risks of twins are actually more than double those of a singleton (Table 2). 10–14 With the exception of one recent Israeli experience,12 the European, Australian, and U.S. data have been very similar during the 1990s. Twin pregnancies are at significantly increased risk of a variety of adverse outcomes. Some of the increased risks are attributable to monozygotic twins, and not all databases adequately make the distinction. In general, these studies have the credibility that comes from very large samples of pregnancies in a variety of medical systems. However, 3 reasons limit how forcefully one can draw conclusions from these studies. Precise controls of antenatal conditions are difficult, and without such controls, it is impossible to eliminate alternative explanations of these outcomes. Patients who undergo in vitro fertilization tend to be of higher socioeconomic status and more health conscious than the general population, but they also are older and at higher risk. In addition, for certain subgroups, the data are open to multiple interpretations. Zhang and his colleagues, for example, found that older women in the U.S. carrying triplets actually had fewer adverse outcomes relative to a 25- to 29-year-old population than they would have had had they been carrying singletons, with twin pregnancies falling in the middle.15 Such studies also raise a host of questions regarding the impact of ART on birth outcomes.5,16–19 However, there is an emerging awareness about the risks of multiple pregnancies, challenging the perception that twins do "well enough," or "almost as well as singletons."20 Some countries have legally mandated reductions in numbers of embryos transferred, and attempts have been made to make physicians and patients aware of the risks of multifetal pregnancies.20


View this table:
[in this window]
[in a new window]
  		Table 2. Summary of Twin Versus Singleton Prenatal Outcomes

 

In this context, we reflect on more than 15 years of experience shared by other colleagues. Our collaborative reports have shown continuous improvements in outcomes with multifetal pregnancy reduction in experienced hands.4 Moreover, the evolution of the demographics of patients using ARTs explains who the multifetal pregnancy patients are who seek reduction.4–6 Our experience of patients with triplets who reduced to twins shows an average maternal age of 37 years. For those patients with triplets who reduced to a singleton, the average age was 42 years. The use of chorionic villus sampling (CVS) before reduction has become a mainstay of our practice to assure the likelihood of normal, remaining fetuses.

Until recently, we did not offer the option of reduction to a singleton from any starting number except in the most extreme of cases, for example, previous twin loss because of uterine anomalies or significant maternal disease.2–4 However, with aging patient demographics, increasing safety of the procedure at our center, more knowledge about the risks of twins, and the trend of easing restrictions on indications for reproductive technologies as they proved safe and effective, we have reduced twins to a singleton in a small percentage of patients and report the results below.


   MATERIALS AND METHODS
TOP
ABSTRACT
 MATERIALS AND METHODS
RESULTS
 DISCUSSION
 REFERENCES
 
Patients referred to Mark I. Evans between 1994 and 2003 who wished to reduce twins to a singleton were included in the study. They were counseled as to risks and benefits. Approval for this study was obtained from the St. Luke's Roosevelt Institutional Review Board. For patients aged more than 30 years or who received eggs from donors aged more than 30 years, CVS was offered before multifetal pregnancy reduction to maximize the likelihood of a normal fetus remaining. Chorionic villus sampling and multifetal pregnancy reduction were usually performed at about 11 weeks of gestation. In most cases fluorescence in situ hybridization analysis for chromosomes 13, 18, 21, X, and Y was performed to confirm diploid counts before proceeding to multifetal pregnancy reduction Between 1996 and 2003, data from all patients seen, including demographics, method of pregnancy initiation, use of genetic diagnosis, and outcomes were collected contemporaneously, usually by phone follow-up, and then analyzed by t test and {chi}2, as appropriate with P < .05 considered significant. Control populations consisted of twin gestations as gathered from the National Vital Statistics Reports of the Centers for Disease Control, Society of Assisted Reproduction Technology database,5,6,21,22 biochemical screening databases of twins, and from multiple other published studies.6–14,10–17,21–23


   RESULTS
TOP
ABSTRACT
 MATERIALS AND METHODS
 RESULTS
DISCUSSION
 REFERENCES
 
During the study period, 52 cases of reduction of twins to a singleton were performed. The percentage of such patients has remained low over the past several years, representing less than 3% of all cases performed by the operator. Forty of the 52 patients were aged 35 years or more, 19 were older than 40 years, and 2 were older than 50 years. The age range was 32–54 years (Table 3). The mean age of our patient population reducing from triplets to twins has remained approximately 37–38 years, but there has been a gradual increase in the upper range of ages of those reducing to a singleton. In comparison for triplets-to-singleton reduction the mean age has been 42 years. In this cohort, the standard deviation of the population has been increasing, which reflects a predominance of patients in their upper 40s or 50s using donor eggs.


View this table:
[in this window]
[in a new window]
  		Table 3. Categorization by Methods, Testing, and Outcomes

 

Forty-one of the 52 patients were fertility treatment patients, of whom 9 used donor eggs (17%). Eleven (21%) of the 52 were natural twin conceptions. Since 1999, 23 of 28 patients have had CVS before reduction to a singleton. Patients who underwent in vitro fertilization with "younger" donor eggs seem less likely to have CVS than those using their own eggs. There are too few cases for statistical significance. There were no fetal losses from the time of CVS to the multifetal pregnancy reduction. One of the 52 patients miscarried at 12 weeks (2.5%), and the mean gestational age at delivery was 37.2 weeks. One remaining fetus later developed mild hydrocephalus, and the pregnancy was terminated at 21 weeks of gestation. Another who delivered at 30 weeks of gestation was later diagnosed with cerebral palsy. One baby born at 25 weeks of gestation weighed less than 1,500 g (1.9%), and 4 weighed less than 2,500 g (7.6%).


   DISCUSSION
TOP
ABSTRACT
 MATERIALS AND METHODS
 RESULTS
 DISCUSSION
REFERENCES
 
Since its inception, proportionately few multifetal pregnancy reductions to a singleton have been performed because of concerns of unknown risk and ethical questions about the justification for reduction of twins to 1 fetus. However, spontaneous twin losses average 10% (and even higher in the Society for Assisted Reproductive Technologies group).21 With increased experience, multifetal pregnancy reduction is clearly safer than in the early stages of its development. Ideally, a rigorous clinical trial that compared outcomes of multifetal pregnancy reduction with unreduced cases would be optimal but very difficult to design and conduct. Case-controlled studies have been performed within limitations.4,23 Although extensive statistical comparisons are premature because of limited numbers of cases performed and variable completeness of control groups, our data suggest that parents who choose to reduce twins to a singleton may have a higher likelihood of taking home a baby than pregnancies remaining with twins.13–17 Our intent is not to encourage twin reduction as a widely used practice but to mark a particular juncture in the cultural evolution of human understanding of twins.

Historically, in our collaborative series over the years approximately 1% of all babies born after reduction have had significant morbidity issues, which is actually lower than the expected general population.4,23 We have insufficient data to comment on the incidence of the one in utero finding (hydrocephalus discovered at about 20 weeks of gestation, the pregnancy terminated) and a baby who developed cerebral palsy after premature delivery at 30 weeks of gestation. However, it is well appreciated that the incidence of neonatal encephalopathy and cerebral palsy are mostly correlated with prematurity.24

The natural outcomes of twin pregnancies are a function of how early in pregnancies one establishes the denominator. Leridon25 in 1977 suggested that live births were only about 20% of conceptions. Boklage26 calculated twins’ births for 81% of twin pregnancies after documentation of a 6-week viable gestation.26 Loss rates for twin pregnancies monitored beginning at the time of second-trimester biochemical screening had about a 6% loss rate. More recently, Glinianaia et al27 reported from the Multiple Pregnancy Registry of Northern England that 194 of 1,852 (10.5%) twins were miscarried before 24 weeks of gestation, and the prenatal and infant mortality rates were 40.6 and 32.6 per 1,000, respectively. The 2002 United States National Vital Statistics Report on Births for 2001 reported births at less than 32 weeks of gestation to be more than 7 times higher for twins than singletons, and at less than 37 weeks of gestation to be 5.5 times that of singleton rates. The incidence of twins weighing less than 1,500 g and weighing at less than 2,500 g were both 9-fold higher than for singletons.6–8 Patients in our series had outcomes closer to singletons than the starting twins. The risks of early death are about 5 times higher for twins, and the risks for cerebral palsy are likewise higher (Fig. 1). 14



View larger version (28K):
[in this window]
[in a new window]
  		Fig. 1. Comparison of twins, singletons, and reduced cases. The incidence of premature delivery, low birth weight, and mortality after reduction are closer to singleton values than twins. Values are percentages except mortality rate, which is per 1,000.

Evans. Reduction of Twins to a Singleton. Obstet Gynecol 2004.

 

The incidence of cerebral palsy has been also shown to be higher in twins than in singletons even when accounting for prematurity, per se.11 In counseling patients with twins known in the late first trimester, we draw on the literature to estimate a loss rate of 8–10% and for morbidity rates to be slightly more than double compared with singletons. The increase in maternal risks in twin pregnancies has also long been appreciated.14

Can the reduction of twins to a singleton be ethically justified? Restricted only to centers with experience? Broadly withheld until research is performed on the manifest and latent consequences? We have partial answers to each of these questions. We lack space for a full argument and will do so in another forum. Our discussion will address the moral implications of the choice of words for debate and discussion, answer moral objections to multifetal pregnancy reduction in twins, and propose a moral compromise for the near-term future.

The choice of words is a moral choice. Normal human beings usually choose their words after having made habitual and partial moral judgment. We can, however, practice self-examination. We can examine the options before choosing words for debate. Or, we can remain in a state of moral certainty and hurl words like weapons. Discussions and debates, especially about reproductive ethics, are "heated" because the judgments made are so deeply rooted in unexamined world views, moral beliefs about women and fetuses, and convictions about the intrinsic value of human life.

To some, "reduction" sounds like a euphemism to cover a surgical approach to the hazards of multiple pregnancies; the end result appears to be only that 1 twin is killed for the other's benefit. Of course, morally speaking, much more is happening. To others, the term is more neutral and benign because it follows a prior judgment that it is certainly always right to help a single woman or a couple with an unplanned or unwanted pregnancy of any number. To ears that have never heard the fear and anxiety in multifetal pregnancies, "reduction" appears to be a soft cover for hard choices, that is, continuation, adoption, reduction, or abortion.

In 1996, Rorty and Pinkerton28 discussed the ethics of "elective fetal reduction." They posed a case of a 33-year-old woman carrying twins. She has 2 children at home. Feeling threats to her marriage, family resources, and from the prospect of 4 children, she requests reduction to a singleton. Rorty and Pinkerton defended reduction after infertility treatment but not in natural twins. They said that twins pose only a slightly higher risk to maternal health than a singleton. They further argued that 1) infertility treatment creates moral claim on the physician to remedy unwanted results, 2) there are no medical indications for twin reduction, 3) the procedure poses risks to the surviving fetus, 4) there is no morally justified way to choose between twins, and 5) reduction in natural twins trivializes the moral seriousness of selective abortion after prenatal diagnosis and is a precedent for eugenics.

Rorty and Pinkerton28 invited new evidence on safety but limited the moral options to continuation, termination, or placing 1 twin for adoption.28 They cited one of us (M.I.E.) for support, who had written that physicians need not be "merely technicians to our patients’ desires."2 We briefly respond.

Data in Table 2 speak to Rorty and Pinkerton's28 first objection. Compared with singletons, the higher incidence of premature delivery of twins and complications for the woman add up to more than "slightly higher" risk to maternal health in premature delivery, preeclampsia, hemorrhage, and rarely even death.14

At the time, Rorty and Pinkerton28 saw no medical indications for twin reduction, absent genetic or maternal health reasons. Table 2 is relevant to differential risks and outcomes for infants. Data from several major studies now make twin reduction a reasonable consideration for medical reasons. When Rorty and Pinkerton did their research, studies comparing mortality and morbidity in twin and singleton pregnancies were mainly in the early stages.

For example, large international studies of Blondel and Kaminski29 showed that twins contributed a much larger proportion of preterm deliveries and low birth weight newborns than did triplets.6–8,29 He wrote that "preventive interventions should not be restricted to triplets, but should also include twins."29 We come to a similar but less directive conclusion.

Obstetricians can provide an unbiased process of education and counseling about the comparative risks of twin and singleton pregnancies. Counseling about a woman's options, including reduction, can now be part of prenatal care in twin pregnancies. The subject may be difficult for both physicians and patients because of a culturally sanctioned stopping point of twins in multiple pregnancies. An invisible hand guided by cultural views permitted both physicians and patients unquestioningly to consider twins as a reasonable medical–moral compromise. With new knowledge comes a new duty to offer all options that are legal in this society, to educate the patient about the options (including the fact that the long-term effects of twin reduction are unknown), help her with weighing her choices in the context of her values, and support her choice if the circumstances warrant. Law is the floor of morality but not the ceiling. Physicians who disagree with what the law permits have a self-respecting way to decline to be involved at all with such options.

Rorty and Pinkerton28 argue for a morally relevant difference between the physician as helper in twin pregnancies after infertility treatments but not so in natural twins.28 Treatment creates claims to help with an unwanted number of fetuses, but why not help in any twin pregnancy? Unintentionally, Rorty and Pinkerton could be understood to say that natural twins are morally different from twins conceived with technical help. Except perhaps for cloning, how twins are conceived is morally neutral. Some theologically based ethics are opposed to any "unnatural" interference with coitus. But even here, natural twins do not have more moral status than twins conceived with ART. Bias could also be at work. Natural twins are perceived as "special" children with instant appeal.

Rorty and Pinkerton28 state that there is no morally acceptable way to select between twins for reduction. In practice, the triage priority for selection has been: diagnosed abnormalities, suspicion of abnormality, size discordancy, location, and technical ease.16 If parents want to know the sex and zygosity of the twins, we disclose it. We will discuss the issues of twin reduction and sex selection in another forum. We assume that Rorty and Pinkerton would agree that criteria for selection need much more study.

Finally, Rorty and Pinkerton28 argue that to reduce twins for social reasons undermines the gravity of medical indications for selective abortion. They hold that selective abortion is justified only for serious genetic diseases. This argument is good in theory but will have adverse consequences for parents if put into practice. Consensus is impossible because there are cultural as well as individual differences in how people define health and disease.30–32 If parental choice has proven to be the fairest and least morally offensive policy for decisions after prenatal diagnosis, it has the best chance of guiding decisions about twin pregnancies, within constraints, that is, advising patients to reconsider judgments made in haste or anger.

Putting twins up for adoption is sometimes considered by parents. Our patients usually consider it seriously but more often choose reduction. Some couples seek prenatal diagnosis but differ greatly in their understanding of genetic risks.31,32 Couples also seek reduction but differ in how they understand the risks for the twins and the mother.33,34

We have made an exploratory moral commitment to patients and do not plan to reverse it until evidence persuades to the contrary. In some cases of twin pregnancies, we must respond to moral imperatives to reduce or prevent harm and to help parents or individuals who feel that their security and futures are at stake.

Even after an extensive consent process, fetal reduction of any number is emotionally and morally troubling for couples.33–37 The long-term effects of reduction are unknown. Although problematic because of privacy concerns, some follow-up studies could be performed with the approval of an institutional review board and informed, voluntary consent of the participants.

We recommend that the obstetrics community not adopt elective twin reduction as a general practice. Patients can be referred to centers with experience in multifetal pregnancy reduction that also offer counseling about this choice. More cases and case-controlled studies are needed to prove safety and efficacy. We urge other centers to publish their total experience in twin reduction. Our experience is this choice can be right in some cases; however, troubling questions remain about a general practice of twin reduction in obstetrics.

We expect most patients with twins to continue with twins. However, there is a continually increasing proportion of the infertility population aged more than 40 years who for a variety of medical and social reasons only want to have a singleton pregnancy. Data suggest that for such patients, multifetal pregnancy reduction is safer than continuing with twins. As will all other technologies, as its safety and efficacy have been proven, indications will liberalize. In the 1980s and 1990s as multifetal pregnancy reduction was being developed and improved, there was little debate, except among the most strident opponents, that multifetal pregnancy reduction from quadruplets or more was the best way to improve outcomes in such cases. In the last decade, the major debate was over the outcome of triplets. Several studies have addressed that issue, and those with the most data suggest improved outcomes with reduction of triplets to twins. Interestingly, the reduction of triplets to a singleton has a higher loss rate (7% versus 4.5%), but both are much less than attempting to carry the triplets (15%).23 However, for those patients starting with twins, reducing from twins to a singleton seems to significantly lower risks and improve outcomes.


   Footnotes
 
Received September 17, 2003. Received in revised form February 2, 2004. Accepted March 23, 2004.

10.1097/01.AOG.0000128299.57908.90


   REFERENCES
TOP
ABSTRACT
 MATERIALS AND METHODS
 RESULTS
 DISCUSSION
 REFERENCES
 
1. Dumez Y, Oury JF. Method for first trimester selective abortion in multiple pregnancy. Contrib Gynecol Obstet 1986;15:50–3.[Medline]

2. Evans MI, Fletcher JC, Zador IE, Newton BW, Quigg MH, Struyk CD. Selective first trimester termination in octuplet and quadruplet pregnancies: clinical and ethical issues. Obstet Gynecol 1988;71:289–96.[Abstract/Free Full Text]

3. Berkowitz RL, Lynch L, Chitkara U, Wilkins IA, Mehalek KE, Alvarez E. Selective reduction of multiple pregnancies in the first trimester. N Engl J Med 1988;318:1043–7.[Medline]

4. Evans MI, Berkowitz R, Wapner R, Carpenter RJ, Goldberg JD, Ayoub MA, et al. Improvement in outcomes of multifetal pregnancy reduction with increased experience. Am J Obstet Gynecol. 2001;184:97–103.[Medline]

5. Kovalevsky G, Rinaudo P, Coutifaris C. Do assisted reproductive technologies cause adverse outcomes? Fertil Steril 2003;79:1270–2.[Medline]

6. Mathews TJ, Menacker F, MacDorman MF. Infant mortality statistics from the 2000 period linked birth/infant death data set. Natl Vital Stat Rep 2002;50:1–28.[Medline]

7. Martin JA, Hamilton BE, Sutton PD, Ventura SJ, Menacker F, Munson ML. Births: final data for 2002. Natl Vital Stat Rep 2003;52:1–114.[Medline]

8. Tournaye H. ICSI: a technique too far? Int J Androl 2003;26:63–9.[Medline]

9. Pinborg A, Loft A, Schmidt L, Andersen AN. Morbidity in a Danish national cohort of 472 IVF/ICSI twins, 1132 non-IVF/ICSI twins and 634 IVF/ICSI singletons: health-related and social implications for the children and their families. Hum Reprod 2003;18:1234–43.[Abstract/Free Full Text]

10. Scher AI, Petterson B, Blair E, Ellenberg JH, Grether JK, Haan E, et al. The risk of mortality or cerebral palsy in twins: a collaborative population-based study. Pediatr Res 2002;52:671–81.[Medline]

11. Pharoah PO. Neurological outcome in twins [review]. Semin Neonatol 2002;7:223–30.[Medline]

12. Shinwell E. Neonatal and long-term outcomes of very low birth weight infants from single and multiple pregnancies. Semin Neonatal 2002;7:203–9.

13. Kogan MD, Alexander GR, Kotelchuck M, MacDorman MF, Buekens P, Martin JA, et al. Trends in twin birth outcomes and prenatal care utilization in the United States, 1981–1997. JAMA 2000;19:284:335–41.

14. Multiple gestation pregnancy. The ESHRE Capri Workshop Group [review]. Hum Rep. 2000;5:1856–64.

15. Zhang J, Meikle S, Grainger DA, Trumble A. Multifetal pregnancy in older women and perinatal outcomes. Fertil Steril. 2002;78:562–8.[Medline]

16. Glinianaia SV, Rankin J, Renwick M. Time trends in twin perinatal mortality in northern England, 1982–94. Northern Region Perinatal Mortality Survey Steering Group. Twin Res 1998;1:189–95.[Medline]

17. Stromberg B, Dahlquist G, Ericson A, Finnstrom O, Koster M, Stjernqvist K. Neurological sequelae in children born after in-vitro fertilization. Lancet 2002;359:461–5.[Medline]

18. Hansen M, Kurinczuk JJ. Bower C, Webb S. The risk of major birth defects after intracytoplasmic sperm injection and in vitro fertilization. N Engl J Med 2002;346:725–30.[Abstract/Free Full Text]

19. Schieve LA, Meikle SF, Ferre C, Peterson HB, Jeng G, Wilcox LS. Low and very low birth weight infants conceived with the use of assisted reproductive technology. N Engl J Med 2002;346:731–7.[Abstract/Free Full Text]

20. Adashi EY, Barr PN, Berkowitz RL, Braude P, Bryan E, Carr J, et al. Infertility therapy-associated multiple pregnancies (births): an ongoing epidemic. Reproductive Biomedicine On line 2003;7:515–542.

21. American Society for Reproductive Medicine; Society for Assisted Reproductive Technology Registry. Assisted reproductive Technology in the United States: 1999 results generated from the American Society for Reproductive Medicine/Society for Assisted Reproductive Technology Registry. Fertil Steril 2002;78:918–31.[Medline]

22. Toner JP. Progress we can be proud of: U. S. trends in assisted reproduction over the first 20 years. Fertil Steril 2002;78:943–50.[Medline]

23. Yaron Y, Bryant-Greenwood PK, Dave N, Moldenhauer JS, Kramer RL, Johnson MP, et al. Multifetal pregnancy reduction of triplets to twins: comparison with non-reduced triplets and twins. Am J Obstet Gynecol. 1999;180:1268–71.[Medline]

24. Neonatal encephalopathy and cerebral palsy: defining the pathogenesis and pathophysiology: a report by the American College of Obstetricians and Gynecologists. Washington, DC: American College of Obstetricians and Gynecologists; 2003.

25. Leridon H. Human fertility: the basic components. Chicago, (IL): University of Chicago Press; 1977.

26. Boklage CE. Survival probability of human conceptions from fertilization to term. Int. J Fertil. 1990;35:79–80, 81–94.

27. Glinianaia SV, Rankin J, Wright C, Sturgiss SN, Renwick M, for the Northern Region Perinatal Mortality Survey Steering Group. A multiple pregnancy register in the north of England. Twin Res 2002;5:436–9.[Medline]

28. Rorty MV, Pinkerton JV. Elective fetal reduction: the ultimate elective surgery. J Contemp Health Law & Policy. 1996;13:53–77.

29. Blondel B, Kaminski M. The increase in multiple births and its consequences on perinatal health [review]. J Gynecol Obstet Biol Reprod (Paris) 2002;31:725–40.

30. Fletcher JC. What are society's interests in human genetics and reproductive technologies? Law Med Health Care 1988;16:131–7.[Medline]

31. Kalra SK, Milad MP, Klock SC, Grobman WA. Infertility patients and their partners: differences in the disease for twin gestation. Obstet Gynecol 2003;102:152–5.[Abstract/Free Full Text]

32. Evans MI, Bottoms SF, Critchfield GC, Greb A. LaFerla JJ. Parental perception of genetic risk: Correlation with prenatal diagnostic procedures. Int J Obstet Gynecol 1990;31:25–28.

33. Britt DW, Mans M, Risinger ST, Evans MI. Bonding and coping with loss: examining the construction of a bonding intervention for multifetal reduction procedures. Fetal Diagn Ther 2001;16:158–65.[Medline]

34. Britt DW, Risinger ST, Mans M, Evans MI. Devastation and relief: conflicting meanings in discovering fetal anomalies. Ultrasound Obstet Gynecol 2002;20:1–5.[Medline]

35. Tadin I, Roje D, Banovic I, Karelovic D, Mimica M. Fetal reduction in multifetal pregnancy–ethical dilemmas. Yonsei Med J 2002;43:252–8.[Medline]

36. Britt DW, Risinger ST, Mans M, Evans MI. Anxiety among women who have undergone fertility therapy and who are considering multifetal pregnancy reduction: trends and scenarios. J Mat Fetal Neonatal Med 2003;13:271–8.

37. Chervenak FA, McCullough LB, Wapner R. Three ethically justified indications for selective termination in multifetal pregnancy: a practical and comprehensive management strategy. J Assisted Reprod Genet 1997;12:531–6.




This article has been cited by other articles:


Home page
 Obstet GynecolHome page
E. Quarello, G. Gorincour, and S. Tassy
Fetal Reduction From Twins to a Singleton: Selective Reduction or Partial Abortion?
Obstet. Gynecol., December 1, 2004; 104(6): 1423 - 1424.
[Full Text] [PDF]

Home page
 Obstet GynecolHome page
K. M. Raviele and K. Daus
Fetal Reduction From Twins to a Singleton: Selective Reduction or Partial Abortion?
Obstet. Gynecol., December 1, 2004; 104(6): 1424 - 1424.
[Full Text] [PDF]

This Article
Right arrow Abstract Freely available
Right arrow Full Text (PDF)
Right arrow Alert me when this article is cited
Right arrow Alert me if a correction is posted
Services
Right arrow Similar articles in this journal
Right arrow Similar articles in PubMed
Right arrow Alert me to new issues of the journal
Right arrow Download to citation manager
Citing Articles
Right arrow Citing Articles via HighWire
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Evans, M. I.
Right arrow Articles by Fletcher, J. C.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Evans, M. I.
Right arrow Articles by Fletcher, J. C.
Related Collections
Right arrow Ethics
Right arrow Genetics and teratology
Right arrow Prenatal Diagnosis
Right arrow Abortion

HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS