Danish National In-Vitro Fertilization Registry 1994 and 1995: a controlled study of births, malformations and cytogenetic findings

Deciding how many embryos to transfer after in vitro fertilisation: development and pilot test of a decision aid

OBJECTIVE

When deciding how many embryos to transfer during in vitro fertilisation (IVF), clinicians and patients have to balance optimizing the chance of pregnancy against preventing multiple pregnancies and the associated complications. This paper describes the development and pilot test of a patient decision aid (DA) for this purpose.

METHODS

The development of the DA consisted of a literature search, establishment of the format, and a pilot test among IVF patients. The DA development was supervised by a panel of experts in the fields of subfertility, obstetrics and DA-research and it was based on the criteria of the International Patient Decision Aid Standards.

RESULTS

One Cochrane review and 34 articles were selected for the DA content. The DA presents information in text, summaries, tables, figures and through an interactive worksheet. The DA was reviewed positively and as acceptable for use in clinical practice by patients and professionals.

CONCLUSION

The DA was thoroughly developed and is likely to be helpful for the decision-making process for the number of embryos transferred after IVF.

PRACTICE IMPLICATIONS

Physicians and researchers can use the DA without restriction in clinical practice or research related to decision-making.

Genomic assessment of follicular marker genes as pregnancy predictors for human IVF

Embryo selection efficiency in human IVF procedure is still suboptimal as shown by low pregnancy rates with single embryo transfer (SET). Bidirectional communication between the oocyte and follicular cells (FC) is essential to achieve developmental competence of the oocyte. Differences in the gene expression profile of FCs from follicles leading to pregnancy could provide useful markers of oocyte developmental competence. FCs were recovered by individual follicle puncture. FC expression levels of potential markers were assessed by Q-PCR with an intra-patient and an inter-patient analysis approach. Using gene expression, a predictive model of ongoing pregnancy was investigated. Using intra-patient analysis, four candidate genes, phosphoglycerate kinase 1 (PGK1), regulator of G-protein signalling 2 (RGS2), regulator of G-protein signalling 3 (RGS3) and cell division cycle 42 (CDC42) showed a difference between FCs from follicles leading to a pregnancy or developmental failure. The best predictors for ongoing pregnancy were PGK1 and RGS2. Additionally, inter-patient analysis revealed differences in FC expression for PGK1 and CDC42 between follicles leading to a transferred embryo with positive pregnancy results and those with negative results. Both inter-patient and intra-patient approaches must be taken into consideration to delineate gene expression variations in the context of follicular competence. A predictor model using biomarkers could improve the efficiency of predicting developmental competence of oocytes. These new approaches provide useful tools in the context of embryo selection and in the improvement of pregnancy rates with SET.

Twins born following assisted reproductive technology: perinatal outcome and admission to hospital

BACKGROUND

Compared with spontaneously conceived (SC) singletons, adverse perinatal outcome, neonatal intensive care unit (NICU) admission and hospital admission in infancy are more common in those born following Assisted Reproductive Technology (ART). Similar comparisons for twins have shown conflicting results.

METHODS

We investigated perinatal outcome and hospital admission during the first 3 years of life for all twin children born in Western Australia between 1994 and 2000 [700 ART, 4097 SC].

RESULTS

ART twins had a greater risk of adverse perinatal outcome including preterm birth, low birthweight and death compared with SC twins of unlike-sex. In their first year of life, ART twins had a longer birth admission; were 60% more likely to be admitted to a NICU; and had a higher risk of hospital admission. The increased risk of hospital admission continued in the second and third year but was not statistically significant in the third year.

CONCLUSIONS

Couples undertaking ART should be aware that in addition to the known increased perinatal risks associated with a twin birth, ART twins are more likely than SC twins to be admitted to a NICU and hospitalized in the first 3 years of life.

In vitro fertilisation policy in Israel and women's perspectives: the more the better?

Israel offers nearly full funding for in vitro fertilisation (IVF) to any Israeli woman irrespective of her marital status or sexual orientation, until she has two children with her current partner. Consequently, Israeli women are the world's most intensive consumers of IVF. This 2006 study explored the perceptions of Israeli IVF patients about the treatment and their experiences, probing possible links between state policy and women's choices and health. Israeli women (n=137), all currently undergoing IVF, were invited to fill out questionnaires. The questionnaires were delivered in five IVF centres by university nursing students or by the clinics' nurses. Most women were optimistic they would become pregnant, and described the treatment as having modest or no negative effects on their lives. They expressed a sweeping commitment to IVF, which they were willing to repeat "as many times as needed". At the same time, the majority appeared to have very partial treatment-related knowledge and marginalised side effects, even though they had experienced some themselves. We interpret the observed favourable image of IVF as closely related to the encouragement implied in the extensive state funding of IVF and in the Jewish Israeli tradition of pronatalism, which may account for the virtual absence of critical public debate on the subject.

Intracytoplasmic sperm injection (ICSI)--what are the risks?

In vitro fertilization used in combination with intracytoplasmic sperm injection allows otherwise sterile couples to become parents. Despite recent studies on the safety of these technologies, there is still only an incomplete picture of the risks associated with the usage of these assisted reproductive techniques to offspring. The risk of multiple gestations continues to be of major concern because of its association with low birth weight, preterm delivery, and increased perinatal mortality. This article outlines the risks associated with in vitro fertilization/intracytoplasmic sperm injection as a well-defined treatment for couples with severe male factor infertility.

Neonatal outcome of 937 children born after transfer of cryopreserved embryos obtained by ICSI and IVF and comparison with outcome data of fresh ICSI and IVF cycles

BACKGROUND

To evaluate the safety of cryopreservation in combination with IVF and ICSI, prenatal diagnosis and neonatal outcome were investigated in children conceived from frozen-thawed ICSI embryos (cryo ICSI) and frozen-thawed IVF embryos (cryo IVF). Data were also compared with earlier published results from fresh ICSI and IVF embryos.

METHODS

Questionnaire data and results of physical examination at 2 months of 547 cryo ICSI children and 390 cryo IVF children were compared, and these were also compared with those of infants born after transfer of fresh embryos.

RESULTS

Birth characteristics were comparable for cryo ICSI and cryo IVF infants. Cryo singletons showed a trend towards higher mean birthweight compared with fresh singletons, in ICSI and IVF, reaching significance when all cryo (ICSI plus IVF) singletons were considered. Low birthweight rate according to multiplicity was comparable between the fresh and the cryo groups, in ICSI and IVF. Non-statistically significantly increased rates of de novo chromosomal anomalies (3.2%) were found in cryo ICSI fetuses/children compared with the fresh ICSI group (1.7%) (OR 1.96; 95% CI 0.92-4.14). Major malformations were more frequently observed in cryo ICSI live borns (6.4%) than in cryo IVF live borns (3.1%) (OR 2.15; 95% CI 1.10-4.20) and fresh ICSI live borns (3.4%) (OR 1.96; 95% CI 1.31-2.91).

CONCLUSIONS

In cryo ICSI compared with cryo IVF, prenatal and neonatal outcome results were comparable, except for a higher major malformation rate in the cryo ICSI group. In the total cryo group compared with the total fresh group, we found a higher mean birthweight in singletons and a higher major malformation rate in live borns.

Safety of assisted reproduction, assessed by risk of abnormalities in children born after use of in vitro fertilization techniques

Assisted reproductive technologies are increasingly used in the treatment of both male and female infertility. The techniques, including in vitro fertilization, with or without intracytoplasmic sperm injection as an adjunctive treatment, represent a tremendous step forward for infertile couples who previously had no treatment options. As we move towards the 30(th) anniversary of the birth of the first baby conceived by in vitro fertilization, questions about the safety of these procedures linger. We review here the available literature regarding the safety of assisted reproductive technologies; these data are made far more robust by the inclusion of long-term follow-up data from the first generation of children arising after the introduction of these technologies.

The risk of malformation following assisted reproduction

INTRODUCTION

Intracytoplasmatic sperm injection (ICSI) is currently the most frequently used human reproductive technology in Germany. ICSI was introduced as routine, insurance-funded medical care in 2002 by the Federal Joint Committee. A re-evaluation of published literature on malformation rates in children born of ICSI pregnancies within a period of three years formed part of the committee's decision. The analysis investigated whether ICSI increases the risk of malformation in the offspring, compared to in vitro fertilization (IVF) and natural conception.

METHODS

Systematic literature review.

RESULTS

929 studies were identified. Three meta-analyses, 15 studies investigating malformations, and 12 studies analyzing imprinting disorders were included. The risk of malformation was not significantly different in nine studies comparing ICSI versus IVF. Two meta-analyses and three of eight cohort studies and retrospective analysis showed significantly more severe malformations after assisted reproduction than after natural conception. The remaining five studies displayed no significant results. Current evidence does not show a higher risk of major malformations in the offspring resulting from the use of ICSI compared to IVF. However, there is evidence that both techniques increase the risk for major malformations considerably, compared to natural conception, and further research is needed. The validity of the results is low since the studies were heterogeneous and the cohorts used in the studies had limited comparability.

Outcomes of multifetal pregnancies

AIM

To determine the outcomes of multifetal pregnancies and to compare maternal and neonatal complications between spontaneously conceived and assisted reproductive therapy.

METHODS

A retrospective analysis was conducted of the information from medical records relating to all multifetal pregnancies. The outcomes were analyzed and used for a comparison between spontaneous and assisted multifetal pregnancies.

RESULTS

There were 387 multifetal pregnancies during the study period, which was 1.3% of all the deliveries; 334 cases (86.3%) were spontaneous conceptions and 53 cases (13.7%) were the result of assisted reproductive therapy. Higher-order fetuses (> or =3) represented 8% of all multifetal pregnancies, 13% in the spontaneous group and 87% in the assisted group. The overall cesarean delivery rate was 73.9%. The assisted reproductive therapy group had a cesarean rate of 90.6% compared with 71.3% in the spontaneous group (P = 0.008). The assisted multifetal pregnancy group had more preterm labors and a longer maternal hospital stay than the spontaneous group. One maternal death occurred in the assisted group. The main causes of early neonatal death were prematurity, infection and congenital malformation. The newborns in the assisted group had more complications than the spontaneous group; most notable were respiratory distress syndrome, newborn intensive care admission, infection and longer hospital stay (6 days vs 15 days, P < 0.001). More complications occurred in higher-order fetuses than with twins.

CONCLUSIONS

Assisted multifetal pregnancies were more likely to be delivered by cesarean section and had a higher rate of higher-order fetuses, preterm birth and neonatal prematurity-related complications with a longer hospital stay in both mothers and newborns, than spontaneous multifetal pregnancies.

Effect of embryo quality on pregnancy outcome following single embryo transfer in women with a diminished egg reserve

OBJECTIVE

To evaluate independently the effect of blastomere number and degree of fragmentation on pregnancy outcome following single ETs in women with a decreased egg reserve.

DESIGN

Retrospective cohort analysis.

SETTING

In vitro fertilization center of a university-based practice.

PATIENT(S)

Women having a single ET related to a decreased egg reserve. A requirement for inclusion was a day 3 serum FSH >12 mIU/mL and < or =3 antral follicles on ultrasound.

INTERVENTION(S)

Patients received no or minimal stimulation with gonadotropins.

MAIN OUTCOME MEASURE(S)

Pregnancy rates (PRs) following single ETs were evaluated according to blastomere number (group 1, < or =4 cells; group 2, 5 cells; group 3, 6 cells; group 4, 7 cells; and group 5, > or =8 cells) and fragmentation index (A, no fragmentation; B, 1-25% fragmentation; and C, >25% fragmentation). Embryo transfers and morphologic evaluation were performed on day 3.

RESULT(S)

The clinical and delivered PRs according to blastomere number showed that 6-8-cell embryos were six times more likely to implant than 4-5-cell embryos (6.6% versus 40.4% clinical). Degree of fragmentation did not predict outcome nearly as well as blastomere number. The overall clinical and delivered PRs per transfer were 27.8% and 24.1%, respectively, and were 14.8% and 12.8% per retrieval, respectively, and were 9.0% and 7.3% per initiated cycle, respectively.

CONCLUSION(S)

Six, seven, or eight-cell embryos have equal chances of implanting in women with day 3 elevated serum FSH. The key finding is that these embryos do better than those with <6 blastomeres. These data may be helpful in women with a diminished ovarian reserve in attempting IVF with their own eggs or when choosing donor oocytes.

Guidelines for the number of embryos to transfer following in vitro fertilization

OBJECTIVE

To review the effect of the number of embryos transferred on the outcome of in vitro fertilization (IVF), to provide guidelines on the number of embryos to transfer in IVF-embryo transfer (ET) in order to optimize healthy live births and minimize multiple pregnancies.

OPTIONS

Rates of live birth, clinical pregnancy, and multiple pregnancy or birth by number of embryos transferred are compared.

OUTCOMES

Clinical pregnancy, multiple pregnancy, and live birth rates.

EVIDENCE

The Cochrane Library and MEDLINE were searched for English language articles from 1990 to April 2006. Search terms included embryo transfer (ET), assisted reproduction, in vitro fertilization (IVF), ntracytoplasmic sperm injection (ICSI), multiple pregnancy, and multiple gestation. Additional references were identified through hand searches of bibliographies of identified articles.

VALUES

Available evidence was reviewed by the Reproductive Endocrinology and Infertility Committee and the Maternal-Fetal Medicine Committee of the Society of Obstetricians and Gynaecologists of Canada and the Board of the Canadian Fertility and Andrology Society, and was qualified using the Evaluation of Evidence Guidelines developed by the Canadian Task Force on the Periodic Health Exam.

BENEFITS, HARMS, AND COSTS

This guideline is intended to minimize the occurrence of multifetal gestation, particularly high-order multiples (HOM), while maintaining acceptable overall pregnancy and live birth rates following IVF-ET.

Serum insulin-like growth factor-I (IGF-I) and growth in children born after assisted reproduction

CONTEXT

Concern has been raised about the safety of assisted reproduction techniques for the offspring.

OBJECTIVES

The objective of the study was to investigate postnatal growth and growth factors in children born after intra-cytoplasmatic sperm injection (ICSI) and in vitro fertilization (IVF).

DESIGN

The study had two cohorts: a population-based longitudinal infant cohort 0-36 months [236 ICSI, 173 IVF, 1530 naturally conceived (NC)], and a cross-sectional child cohort at 5 yr (68 ICSI, 67 IVF, 70 NC).

INTERVENTION

Anthropometrical measurements were made at birth, 3, 18, 36 (infant cohort), and 60 months (child cohort), and blood samples were collected at 3 or 60 months.

MAIN OUTCOME MEASURES

Serum IGF-I, IGFBP-3, height, weight, head and abdominal circumference, body mass index, and fat folds were the main outcome measures.

RESULTS

Anthropometrical measurements showed no significant differences between ICSI and IVF children and controls in either cohort. However, singleton ICSI girls [3.4 (0.6) kg, P = 0.008] had a slightly lower birth weight than IVF [3.5 (0.5) kg] and NC girls [3.5 (0.5) kg]. Birth weights of singleton boys [3.6 (0.5) kg], twin boys [2.6 (0.6) kg], and twin girls [2.4 (0.5) kg] did not differ between types of conception. In the infant cohort in 3-month-old singletons, serum IGF-I was lower in ICSI [78 (26) ng/ml] than NC boys [94 (27) ng/ml, P < 0.001] and IVF [74 (34) ng/ml], compared with NC girls [93 (43) ng/ml, P = 0.011]. ICSI children were also smaller than their target height (sd score) at 3 yr of age [mean -0.91 (1.2)], compared with NC children [-0.61 (0.9), P = 0.033]. In the child cohort, target height attainment (sd score) and growth factors did not differ among the three groups.

CONCLUSIONS

The overall growth pattern of ICSI and IVF children in both cohorts was normal. Our findings of subtle differences in target height attainment and serum IGF-I levels between infants born after assisted reproduction techniques and controls may not be clinically significant. However, these observations indicate that further systematic follow-up of growth and puberty in these children is needed.

Practitioner reporting of birth defects in children born following assisted reproductive technology: Does it still have a role in surveillance of birth defects?

BACKGROUND

National assisted reproductive technology (ART) data collections that rely on practitioners' reports of birth defects have consistently reported lower proportions of children with birth defects than record linkage studies that link ART infants to birth and malformation registers.

METHODS

We compared the birth defect data reported to the national Australian Assisted Conception Data Collection (ACDC) by practitioners at three Western Australian ART clinics with the birth defect data identified on the Western Australian Birth Defects Registry (WABDR) through record linkage of all the pregnancies conceived at these clinics to the WABDR. Cases are reported to the WABDR by multiple statutory and voluntary sources.

RESULTS

We found that the national ACDC significantly underestimated the prevalence of birth defects in WA-born ART infants. Less than one-third of ART children identified with a major birth defect on the WABDR were reported to the ACDC.

CONCLUSIONS

Although national ART data collections provide valuable information on pregnancy rates and short-term pregnancy outcomes such as multiple birth and birth weight, we strongly recommend that birth defect information used for patient counselling is preferentially drawn from large studies that have used record linkage to high-quality birth defect registers.

Naturally conceived twins with monochorionic placentation have the highest risk of fetal loss

OBJECTIVE

The aim of this study was to estimate the rate of fetal loss in dichorionic (DC) and monochorionic (MC) twin pregnancies stratified according to zygosity and method of conception.

METHODS

In a prospective multicenter observational study women with a twin pregnancy had an ultrasound scan before 14 + 6 weeks' gestation in order to determine chorionicity. The fetal loss rate, the perinatal, neonatal and infant mortality rates and the frequency of very preterm labor were estimated for the different types of twin.

RESULTS

Among the 495 pregnancies (421 DC and 74 MC) 229 (46%) were conceived naturally and 266 (54%) by assisted reproduction (AR). Outcome data for 945 liveborn babies were obtained. The spontaneous miscarriage rate before 24 weeks' gestation was 10.9% (7/64) among naturally conceived MC compared to 3.0% (5/165) for naturally conceived DC twins (P < 0.05). For twins conceived by AR the corresponding figures were 0% (0/10) and 0.4% (1/256). The odds ratio (OR) for very preterm birth-before 28 weeks' gestation-was 4.2 for MC twins compared to DC twins. The relative risk of fetal loss or death among DC twins was 20% of the risk for MC twins.

CONCLUSION

The risk of fetal loss, very preterm delivery and neonatal/infant death is significantly higher among twins with MC compared to DC placentation. Twins conceived by AR have a much lower risk of MC placentation. The risk of losing one or both twins seems higher among naturally conceived twins compared to twins conceived by AR, despite the fact that the maternal age was higher among the mothers of the AR twins.

Infertility, infertility treatment, and congenital malformations: Danish national birth cohort

OBJECTIVES

To examine whether infertile couples (with a time to pregnancy of > 12 months), who conceive naturally or after treatment, give birth to children with an increased prevalence of congenital malformations.

DESIGN

Longitudinal study.

SETTING

Danish national birth cohort.

PARTICIPANTS

Three groups of liveborn children and their mothers: 50,897 singletons and 1366 twins born of fertile couples (time to pregnancy < or = 12 months), 5764 singletons and 100 twins born of infertile couples who conceived naturally (time to pregnancy > 12 months), and 4588 singletons and 1690 twins born after infertility treatment.

MAIN OUTCOME MEASURES

Prevalence of congenital malformations determined from hospital discharge diagnoses.

RESULTS

Compared with singletons born of fertile couples, singletons born of infertile couples who conceived naturally or after treatment had a higher prevalence of congenital malformations-hazard ratios 1.20 (95% confidence interval 1.07 to 1.35) and 1.39 (1.23 to 1.57). The overall prevalence of congenital malformations increased with increasing time to pregnancy. When the analysis was restricted to singletons born of infertile couples, babies born after treatment had an increased prevalence of genital organ malformations (hazard ratio 2.32, 1.24 to 4.35) compared with babies conceived naturally. No significant differences existed in the overall prevalence of congenital malformations among twins.

CONCLUSIONS

Hormonal treatment for infertility may be related to the occurrence of malformations of genital organs, but our results suggest that the reported increased prevalence of congenital malformations seen in singletons born after assisted reproductive technology is partly due to the underlying infertility or its determinants. The association between untreated infertility and congenital malformations warrants further examination.

Perinatal outcomes of spontaneous twins compared with twins conceived through intracytoplasmic sperm injection

OBJECTIVE

To compare perinatal outcomes in spontaneous twins compared with those conceived by intracytoplasmic sperm injection (ICSI).

DESIGN

Retrospective case-control study.

PATIENTS

Cases consisted of 274 intracytoplasmic sperm injection twins, controls were 348 naturally conceived twins delivered between 1999 and 2003 in a tertiary hospital.

MAIN OUTCOME MEASURES

Birth weight, gestational age at birth, cesarean delivery rate, perinatal mortality and morbidity, congenital anomalies, gestational diabetes and pregnancy induced hypertension.

RESULTS

Preterm deliveries (76.6% vs. 64.1% <37 weeks and 19.7% vs. 13.2% <32 weeks) and low birth weight (73% vs. 60.3% <2500 g and 19.7% vs. 12.6% <1500 g) were significantly higher in the ICSI group compared with controls. Gestational diabetes mellitus (8% vs. 2.9%) and cesarean deliveries (95.2% vs. 77.6%) were more common in cases compared with the control group. There was a significantly higher rate of perinatal morbidity (16.4% vs. 7.8%) and mortality (8% vs. 2.6%) in ICSI twins. The incidence of congenital malformations diagnosed at birth was higher in cases (4.4%) compared with controls (0.9%) but the difference was not significant when adjusted for maternal age.

CONCLUSION

Perinatal outcomes of twins after ICSI treatment are less optimal than naturally conceived twins.

Children born after assisted fertilization have an increased rate of major congenital anomalies

OBJECTIVE

To study the occurrence of major congenital anomalies (CAs) among children born after IVF (IVF, microinjections, and frozen embryo transfers) and after ovulation inductions with or without insemination (other assisted reproductive technologies [ART]).

DESIGN

Register-based study.

SETTING

Data regarding CAs were obtained from the Register of Congenital Malformations.

PATIENT(S)

Children from IVF (n = 4,559), children from other ART (n = 4,467), and controls (n = 27,078, a random sample of naturally conceived children) from the Medical Birth Register.

INTERVENTION(S)

In vitro fertilization and other ART treatment in ordinary practice.

MAIN OUTCOME MEASURE(S)

Rate of major CAs. Children from IVF and other ART were compared with control children, both overall and by plurality, controlling for confounding factors by logistic regression.

RESULT(S)

For IVF children, the adjusted odds ratio (OR) was 1.3 (95% confidence interval [CI], 1.1-1.6). Stratifying by gender and plurality showed that the risk was only increased for boys, and the risk was decreased for multiple IVF girls (OR = 0.5, 95% CI 0.2-0.9). The crude OR of major CA for other ART children was 1.3 (95% CI 1.1-1.5), but adjusted differences by gender and plurality were statistically insignificant.

CONCLUSION(S)

In vitro fertilization was associated with an increased risk for major CAs among singleton boys and a decreased risk among multiple girls. The risk after other ART was only slightly increased.

Risk of birth defects among children conceived with assisted reproductive technology: providing an epidemiologic context to the data

Studies of assisted reproductive technology (ART) and birth defects must be scrutinized and appropriately interpreted in the context of their limitations. The recent findings reported by Klemetti et al. are compelling, given the study's many strengths, and add to the accumulating evidence suggestive of an association between ART and birth defects.

Preterm birth and low birth weight after assisted reproductive technology-related pregnancy in Australia between 1996 and 2000

OBJECTIVE

To describe patterns of preterm birth and low birth weight (LBW) for infants born after assisted reproductive technology (ART) and determine whether these were associated with maternal or treatment characteristics.

DESIGN

Retrospective cohort study of national population data of infants conceived through ART.

SETTING

Australian birth records from 1996 to 2000.

PATIENT(S)

Eighteen thousand, four hundred twenty-nine liveborn and stillborn infants conceived through ART.

INTERVENTION(S)

In vitro fertilization, intracytoplasmic sperm injection, and gamete intrafallopian transfer.

MAIN OUTCOME MEASURE(S)

Preterm birth and LBW.

RESULT(S)

Preterm birth and LBW were more common among singletons and twins conceived with IVF and born to nulliparous mothers. Preterm birth and LBW were, respectively, 1.3 times and 1.5 times more likely to occur among singletons conceived by transfer of fresh embryos, compared with transfer of frozen embryos. Preterm birth and LBW was more common among couples who had female-factor infertility compared with male-factor infertility.

CONCLUSION(S)

The transfer of fresh embryos and female-factor infertility were independently associated with preterm birth and LBW for both singletons and twins after ART.

Outcomes From Assisted Reproductive Technology

The use of assisted reproductive technology (ART) for treating the infertile couple is increasing in the United States. The purpose of this paper is to review the short-term outcomes after ART. Pregnancy rates after ART have shown nearly continuous improvement in the years since its inception. A number of factors affect the pregnancy rate, with the most important being a woman's age. Certain clinical diagnoses are associated with a poorer outcome from ART, including the presence of hydrosalpinges, uterine leiomyomata that distort the endometrial cavity, and decreased ovarian reserve. Multiple gestations are the major complication after ART. New laboratory techniques, including extended embryo culture, may allow the transfer of fewer embryos to maintain pregnancy rates while reducing the risk of multiple gestations. Although much of the morbidity in children born after ART is the result of multiples, recent analysis suggests that even singletons are at higher risk for perinatal morbidity, including preterm delivery and small for gestational age infants. In vitro fertilization may be associated with a slight increased risk for birth defects. The major short-term complication of ART in women is the development of ovarian hyperstimulation syndrome. This syndrome is difficult to predict, but new treatments are being developed that may limit its frequency. Because of its high pregnancy rate, couples are moving to ART more quickly in the management of their infertility. All outcomes of ART, including pregnancy rates and adverse complications, need to be compared with standard non-ART therapy when deciding the appropriate course of treatment for a given couple.

Antenatal care in singleton pregnancies after ICSI as compared to spontaneous conception: data from a prospective controlled cohort study in Germany

BACKGROUND

The aim was to compare the antenatal care and the intake of vitamins and medications of infertility patients with singleton pregnancies after ICSI to women with a spontaneously conceived singleton pregnancy.

METHODS

The data on the antenatal care of 2055 singleton pregnancies after ICSI from a prospective controlled multicentre study in Germany were analysed. The prospectively collected data of the control group of 7861 singletons were retrospectively assessed for the present analysis.

RESULTS

The ICSI patients were significantly older (32.9 versus 27.0 years, P<0.019) and more likely to be obese (body mass index>or=30 kg/m2: 13.9 versus 4.8%, P<0.001) than the controls. The control mothers were significantly more likely to smoke (19.2%) or to consume alcohol (23.5%) during pregnancy than the ICSI mothers (7.4 and 0.6% respectively). Only 38.1% of ICSI patients took folic acid before conception. Only 61.7% of ICSI patients received an iodine supplementation at some point during pregnancy. ICSI patients went more regularly to the routine antenatal care consultations at the gynaecologist and had ultrasound examinations performed more regularly than the controls. The absolute number of ultrasound examinations was significantly higher in the ICSI group (13.6+/-6.0 versus 4.1+/-2.4).

CONCLUSION

In spite of the intensive use of antenatal medical care by patients pregnant after ICSI, simple methods, such as the use of supplementary iodine and periconceptional folic acid, were used rarely. This indicates that counselling pregnant patients after ICSI about periconceptional and antenatal care seems to be insufficient in Germany and must be improved.

In vitro fertilization is associated with an increase in major birth defects

OBJECTIVE

To determine the risk of major birth defects in cohorts of children conceived through IVF or through IUI as compared with naturally conceived children.

DESIGN

Retrospective cohort study.

SETTING

Academic medical center.

PATIENT(S)

Children conceived by IVF or IUI at the University of Iowa from 1989 through 2002, compared with a matched cohort of naturally conceived children.

INTERVENTION(S)

None.

MAIN OUTCOME MEASURE(S)

Outcome data were obtained from Iowa state birth and fetal death certificates and from the Iowa Birth Defects Registry.

RESULT(S)

Ninety of 1,462 IVF-conceived children (6.2%) and 17 of 343 IUI-conceived children (5.0%) had a major birth defect, compared with 369 of 8,422 naturally conceived children (4.4%). The adjusted odds ratio of a major birth defect in all IVF-conceived children was 1.30 (95% confidence interval [CI] 1.00-1.67) and 1.11 (95% CI 0.67-1.84) for IUI-conceived children. The birth defect rate was increased after IVF when the analysis was limited to term singletons. Cardiovascular and musculoskeletal defects and known birth defect syndromes were increased after IVF. Among IVF-conceived children, there was no difference in birth defect rates after intracytoplasmic sperm injection (ICSI) or after transfer of cryopreserved embryos.

CONCLUSION(S)

Infants conceived through IVF have a slightly higher rate of major birth defects. More birth defects are noted among children born to infertile couples treated with IUI, although this difference is not statistically significant. Larger studies of infants conceived by infertile couples after all types of infertility treatment are needed to definitively determine whether the increased risk of birth defects is secondary to problems inherent in the infertile couple and/or factors associated with some aspect of the treatment.

Stillbirth and Infant Mortality Among Hispanic Singletons, Twins, and Triplets in the United States

OBJECTIVE

We estimate the impact of increasing fetal number on fetal and infant mortality among Hispanic mothers.

METHODS

Retrospective cohort study involving singletons, twins, and triplets delivered in the United States from 1995 through 2000, except for the analysis on infant mortality in singletons (1995 through 1999). Main outcome measures were stillbirth (> or = 20 weeks) and infant mortality (< 365 days).

RESULTS

A total of 37,489,600 individual births were reviewed, consisting of 36,840,704 singletons, 613,930 twins, and 34,966 triplets. Hispanics accounted for 6,848,027 (18.6%) singletons, 85,887 (14.0%) individual twins, and 2,725 (7.8%) individual triplets. Among singletons, stillbirth (odds ratio [OR] 0.91, 95% confidence interval [CI] 0.90-0.92) and infant mortality (OR 0.85, 95% CI 0.84-0.86) were both lower in Hispanics than in whites. Among twins, Hispanics had a lower risk for infant mortality (OR 0.93, 95% CI 0.88-0.97) but a comparable risk for stillbirth (OR 1.06, 95% CI 0.98-1.13). Although the risk for infant mortality in Hispanic triplets was comparable to that of whites (OR 1.20, 95% CI 0.94-1.54), Hispanic triplets had a 50% higher likelihood of dying in utero (OR 1.50, 95% CI 1.06-2.14).

CONCLUSION

Although Hispanic infants generally show better or comparable survival indices compared with whites, the risk for fetal and infant death in Hispanics increases in fetal number in a dose-dependent fashion, thereby obliterating the Hispanic advantage. The elevated risk for stillbirth among Hispanic triplets is particularly noteworthy and underscores the need for caution in making generalizations of favorable birth outcomes in Hispanics.

Perinatel outcomes of singleton pregnancies achieved by in vitro fertilization: a systematic review and meta-analysis

OBJECTIVE

To determine whether the incidence of adverse obstetric outcomes is higher in singleton pregnancies achieved by in vitro fertilization (IVF) than in spontaneously conceived singletons matched for maternal age.

METHODS

We used comprehensive search strategies to search MEDLINE and EMBASE databases. We selected case-control and cohort studies that compared singleton pregnancies conceived by IVF or intracytoplasmic sperm injection (ICSI) with spontaneously conceived singletons (matched for maternal age [case-control studies] or controlled for maternal age [cohort studies]). Two reviewers independently assessed titles, abstracts, and study quality and extracted data. Statistical analysis was performed with Review Manager for Windows (Version 4.2, Oxford, UK). We performed meta-analysis of dichotomous data, using odds ratios (ORs) as measures of effect size, with a random effects model. We followed the Meta-Analysis of Observational Studies in Epidemiology (MOOSE) guidelines for meta-analysis of observational studies.

RESULTS

Singleton pregnancies resulting from IVF have increased rates of poor obstetric outcome, compared with spontaneously conceived singletons matched for maternal age, with increases in perinatal mortality (OR 2.40; 95% confidence interval [CI] 1.59-3.63), preterm birth at < 33 weeks' gestation (OR 2.99; 95% CI 1.54-5.80), preterm birth at < 37 weeks' gestation (OR 1.93; 95% CI 1.36-2.74), very low birth weight (< 1500 g) (OR 3.78; 95% CI 4.29-5.75), small for gestational age (OR 1.59; 95% CI 1.20-2.11), and congenital malformations (OR 1.41; CI 1.06-1.88).

CONCLUSIONS

IVF singleton pregnancies have increased rates of poor obstetric outcome, compared with spontaneously conceived singletons matched for maternal age.

Gametes and embryo epigenetic reprogramming affect developmental outcome: implication for assisted reproductive technologies

There is concern about the health of children who are conceived with the use assisted reproductive technologies (ART). In addition to reports of low birth weight and chromosomal anomalies, there is evidence that ART may be associated with increased epigenetic disorders in the infants who are conceived using these procedures. Epigenetic reprogramming is critical during gametogenesis and at preimplantation stage and involves DNA methylation, imprinting, RNA silencing, covalent modifications of histones, and remodeling by other chromatin-associated complexes. Epigenetic regulation is involved in early embryo development, fetal growth, and birth weight. Disturbances in epigenetic reprogramming may lead to developmental problems and early mortality. Recent reports suggest the increased incidence of imprinting disorders such as Beckwith-Wiedemann syndrome, Angelman syndrome, and retinoblastoma in children who are conceived with the use of ART. These may result from an accumulation of epigenetic alterations during embryo culture and/or by altered embryonic developmental timing. Further research is urgently needed to determine whether a causal relationship between ART and epigenetic disorders exists. Until then, cautious review of both short-term and long-term ART outcomes at a national level is recommended.

IVF/ICSI twin pregnancies: risks and prevention

Since the 1970s, the national twin birth rates have been increasing worldwide. Apart from the increasing childbearing age, the main cause is the use of assisted reproductive technologies (ART). To explore the overall consequences of dual embryo transfer (DET), the literature has been reviewed systematically regarding short- and long-term outcomes of IVF/ICSI twin pregnancies i.e. pregnancy complications, maternal risks, obstetric outcome and long-term morbidity including neurological sequelae, cognitive development and family implications. Another consequence of DET is vanishing twins, which seems to be a possible cause of adverse outcome in IVF singletons. The sparse literature on vanishing twins in IVF pregnancies and the influence on the surviving co-twin were also addressed. Finally, to determine the effects of implementing elective single embryo transfer (eSET), trials concerning eSET versus DET were analysed. In the light of the steadily increasing twin birth rates and the findings in this overview, where IVF/ICSI twins carry adverse outcome, it should be emphasized that the major obstacle in IVF remains the high twin birth rate. Furthermore vanishing twins account for another hazard of DET. These problems can be resolved by implementing eSET, diminishing the twin birth rate without affecting the overall goal of achieving a healthy infant.

Why do couples refuse or discontinue ART?

The first child born after in-vitro fertilisation, (IVF)-treatment, just passed its 26th birthday in July 2004. Since that birth-assisted reproduction techniques (ART) became a practicable technology, they had been used all over the world, and more than 2 million children were born after IVF-treatment. Despite all success in this field, ART is neither accepted nor used for all infertile couples, although this might be the only possibility of becoming pregnant. Two different kinds of ART refusal are distinguishable: the primary refusal being for financial, psychosocial, moral, ethical and medical reasons including the risk of severe ovarian hyperstimulation syndrome, the risk of multiple pregnancies and the risk of malformations. The secondary refusal includes dropouts after one or more unsuccessful IVF-treatments mainly influenced by the outcome of previous cycles (prognostic factors: oocyte and embryo count, embryo quality, females age) associated with psychological and emotional aspects. However, financial factors seem to be the most potent reasons for ART-refusal.

Racial disparity in fetal growth inhibition among singletons and multiples

OBJECTIVE

The purpose of this study was to determine the magnitude of black-white gap in intrauterine fetal growth inhibition among singletons and multiples.

STUDY DESIGN

This was a cross-sectional study on singleton, twin, and triplet live births in the United States from 1995 through 1998. We compared the risk for low and very low-birth-weight, preterm and very preterm, and small-for-gestational age between black and white neonates.

RESULTS

A total of 14,245,865 singletons (blacks = 16.2%), 392,761 twins (blacks = 18.0%), and 21,436 triplets (blacks = 7.7%) were analyzed. Black neonates depicted significantly higher risks for all indices of fetal growth inhibition regardless of plurality. The gestational age of onset of fetal growth lag for black fetuses was earliest among triplets (23 weeks and the gap remained unchanged) then singletons (26 weeks; maximum gap 37-42 weeks), and finally twins (33 weeks; maximum gap 37-40 weeks).

CONCLUSION

Black-white disparity in fetal growth inhibition varied by plurality subtypes. The different gestational ages of onset of black-white fetal growth divergence could potentially be exploited for targeting intervention measures aimed at narrowing the gap.

Perinatal mortality associated with abruptio placenta in singletons and multiples

OBJECTIVE

This study was undertaken to investigate the association among plurality (number of fetuses per pregnancy), abruptio placenta, and perinatal mortality.

STUDY DESIGN

A retrospective cohort study on 15,051,872 singletons, 413,619 twins, and 22,585 triplets delivered in the United States between 1995 and 1998 was conducted. We compared the occurrence of perinatal death between pregnancies complicated by abruptio placenta and those without with the use of adjusted odds ratios. The generalized estimating equations framework was applied to adjust for intracluster correlations among multiples.

RESULTS

Placental abruption occurred among 93,968 singletons (6.2 per 1000), 5051 twin (12.2 per 1000), and 353 triplet (15.6 per 1000) gestations ( P for trend<.0001). Placental abruption was associated with significant risk of mortality irrespective of the plurality subtype. Perinatal mortality was greatest among singletons (adjusted odds ratio [95% CI]=14.3[13.2-15.4]), followed by twins (4.4[3.9-4.9]) and least among triplets (3.0[2.0-4.6]) ( P for trend<.0001).

CONCLUSION

As plurality increases from 1 to 3, the risk of placental abruption rises, whereas the risk of abruptio-associated perinatal mortality declines.

Perinatal outcomes of in vitro fertilization twins: a systematic review and meta-analyses

OBJECTIVE

Uncontrolled studies suggest that in vitro fertilization twins have increased rates of preterm birth and low birth weight and would warrant increased antenatal monitoring. The objective of this meta-analysis was to determine whether the incidence of poor obstetric outcomes is higher for in vitro fertilization twins than for spontaneously conceived twins who were matched for maternal age.

STUDY DESIGN

Medline and EMBASE were searched with comprehensive search strategies. Case-control and cohort studies of twins who were conceived by in vitro fertilization or in vitro fertilization/intracytoplasmic sperm injection, with the transfer of fresh embryos or cryopreserved (frozen) in women with infertility, and/or whose partners were subfertile or infertile, compared with naturally (spontaneously) conceived twins who were matched for maternal age (case-control studies) or which were controlled for it (cohort studies). Two reviewers independently assessed titles, abstracts, and study quality and extracted the data. Statistical analysis was performed with commercial statistical software. Dichotomous data were meta-analyzed with odds ratios as measures of effect size, and continuous data was meta-analyzed with mean differences. Interstudy variation was incorporated with the assumption of a random effects model for the treatment effect.

RESULTS

Compared with spontaneously conceived twins who were matched for maternal age, in vitro fertilization twins have an increased risk of preterm birth between 32 and 36 weeks of gestation (odds ratio, 1.48; 95% CI, 1.05-2.10), and an elevated risk of preterm birth at <37 weeks of gestation when parity is also matched for an odds ratio of 1.57 (95% CI, 1.01-2.44). There was an increased rate of cesarean delivery among in vitro fertilization twins (odds ratio, 1.33; 95% CI, 1.06-1.67). There were no significant differences in incidences of perinatal death, low birth weight infants, or congenital malformations.

CONCLUSION

In vitro fertilization twins have increased rates of preterm birth compared with spontaneously conceived twins who were matched for maternal age, despite the fact that their outcomes would be expected to be better because of the decreased proportion of monochorionic twins.

A meta-analysis of controlled studies comparing major malformation rates in IVF and ICSI infants with naturally conceived children

PURPOSE

To estimate the risk of major malformations in IVF and ICSI infants.

METHODS

Forty-four studies published in English since 1990 where the major malformation rate for IVF or ICSI cases was compared to an appropriate control group were reviewed. Nineteen studies met all selection criteria. In addition, a quality score was developed to assess each study based on sample size, timing of diagnosis, appropriateness of control group and other factors.

RESULTS

In 19 studies, the major malformation rates ranged from 0-9.5% for IVF; 1.1-9.7 for ICSI; and 0-6.9% in the control groups. When ICSI was compared to IVF, and multiple births compared to singleton, there were no statistically significant differences. When data from 16 studies involving 28,524 IVF infants and 2,520,988 spontaneously conceived controls and 7 studies involving 7234 ICSI infants and 978,078 controls were pooled, we found an overall odds ratio for the 19 studies of 1.29 (95% CI 1.01-1.67).

CONCLUSIONS

The overall odds ratio of 1.29 was statistically significant at the 5% level. These results may be useful for counseling ART patients and properly designing the consent forms used for ART procedures. It is not clear whether this risk is due to the procedures used in ART. We found that some of these studies have design flaws. All of them lacked an appropriate control group, i.e. infertile patients conceiving spontaneously. These flaws may create biases that would in almost all instances increase the risk of major malformations in the study group. Further research with better designed studies will likely result in a better estimate of the risk of major malformations associated with IVF and ICSI.

Long-term outcomes in multiple gestations

Children born from a multiple gestation are at increased risk for cerebral palsy, learning disability, and language and neurobehavioral deficits. With the increased incidence of multiple pregnancies and use of assisted reproductive technology (ART), these issues are more commonly affecting parents. Long-term outcomes are a critical part of preconceptual and early pregnancy counseling for parents faced with a multiple gestation or considering ART, and the provider should be well versed on issues surrounding zygosity, gestational age, higher-order multiples, and the effects of options such as multifetal pregnancy reduction.

Genetics and assisted reproduction technology

In the past 20 years, a significant improvement has been shown in the treatment for infertility in both women and men through the development of in vitro fertilization (IVF) and intracytoplasmic sperm injection (ICSI). Only donated sperm could be previously used for treatment; now oocytes can also be donated. Furthermore, the combination of IVF and ICSI with advanced genetic methods has made preimplantation genetic diagnosis possible for many genetic conditions. These methods enable genetic testing of the early human embryo by using only a single cell, one blastomere biopsied from the embryo, as the sample from which the diagnosis of many chromosome rearrangements and other inherited diseases can be made. It has also been established that a considerable proportion of infertility is caused by genetic defects, which have several implications for infertility treatment. The purpose of this review is to give a concise introduction on how genetics is involved in assisted reproduction technology to specialists who may not be working in this particular field of gynecology, but who would need some knowledge of this for proper care of their patients.

Comparison of outcome of pregnancy after intra-uterine insemination (IUI) and IVF

INTRODUCTION

Pregnancy outcome after IVF has been shown to be worse than after spontaneous conception. There is discussion as to whether this results from the technique itself or the patient characteristics. This study compares pregnancy outcome after IVF and intra-uterine inemination (IUI) in a matched patient group.

METHODS

Data were obtained from our IVF and IUI databases (1997-2001). Matching was performed for maternal age, parity and plurality, and 126 IUI pregnancies were compared with 126 IVF pregnancies. Outcome variables were pregnancy duration, birth weight, Caesarean section rates, preterm contraction rates, neonatal intensive care unit admission, Apgar score, blood loss rates and maternal hypertension.

RESULTS

None of the analysed parameters was statistically different between the groups.

CONCLUSION

This matched case-control study does not show different pregnancy outcomes after IVF and IUI. Since there is no reason to believe that the IUI technique in itself leads to an increased obstetric or neonatal risk, this study suggests that the worse pregnancy outcome after IVF as compared with spontaneous conceptions is due to the specific patient characteristics, rather than to the use of IVF itself.

A multi-centre cohort study of the physical health of 5-year-old children conceived after intracytoplasmic sperm injection, in vitro fertilization and natural conception

BACKGROUND

Over a million children have been born from assisted conception worldwide. Newer techniques being introduced appear less and less 'natural', such as intracytoplasmic sperm injection (ICSI), but there is little information on these children beyond the neonatal period.

METHODS

540 ICSI conceived 5-year-old children from five European countries were comprehensively assessed, along with 538 matched naturally conceived children and 437 children conceived with standard IVF.

RESULTS

Of the 540 ICSI children examined, 63 (4.2%) had experienced a major congenital malformation. Compared with naturally conceived children, the odds of a major malformation were 2.77 (95% CI 1.41-5.46) for ICSI children and 1.80 (95% CI 0.85-3.81) for IVF children; these estimates were little affected by adjustment for socio-demographic factors. The higher rate observed in the ICSI group was due partially to an excess of malformations in the (boys') urogenital system. In addition, ICSI and IVF children were more likely than naturally conceived children to have had a significant childhood illness, to have had a surgical operation, to require medical therapy and to be admitted to hospital. A detailed physical examination revealed no further substantial differences between the groups, however.

CONCLUSIONS

Singleton ICSI and IVF 5-year-olds are more likely to need health care resources than naturally conceived children. Assessment of singleton ICSI and IVF children at 5 years of age was generally reassuring, however, we found that ICSI children presented with more major congenital malformations and both ICSI and IVF children were more likely to need health care resources than naturally conceived children. Ongoing monitoring of these children is therefore required.

Single embryo transfer: a mini-review

This paper provides a concise review of single embryo transfer (SET) in cycles using fresh embryos as well as in cycles using frozen-thawed embryos. Relevant studies were identified by a computerized search in PubMed for the period 1995-2004. The pregnancy rates, delivery rates and multiple pregnancy/birth rates were evaluated after fresh or frozen embryo transfer as well as cumulative delivery rates after fresh and frozen SET. The results of four randomized controlled trials (RCT) and seven observational studies using fresh embryo transfers are analysed. No RCT with SET in freezing-thawing cycles was identified, while one observational study was identified. The effects of a change in the rules from the National Board of Health and Welfare in Sweden in 2003 regarding the implementation of SET in Sweden are summarized.

Assisted reproductive technologies and the risk of birth defects—a systematic review

BACKGROUND

The risk of birth defects in infants born following assisted reproductive technology (ART) treatment is a controversial question. Most publications examining the prevalence of birth defects in ICSI and IVF infants compared to spontaneously conceived infants have serious methodological limitations; despite this, most researchers have concluded that there is no increased risk.

METHODS

We carried out a systematic review to identify all papers published by March 2003 with data relating to the prevalence of birth defects in infants conceived following IVF and/or ICSI compared with spontaneously conceived infants. Independent expert reviewers used criteria defined a priori to determine whether studies were suitable for inclusion in a meta-analysis. Fixed effects meta-analysis was performed for all studies and reviewer-selected studies.

RESULTS

Twenty-five studies were identified for review. Two-thirds of these showed a 25% or greater increased risk of birth defects in ART infants. The results of meta-analyses of the seven reviewer-selected studies and of all 25 studies suggest a statistically significant 30-40% increased risk of birth defects associated with ART.

CONCLUSIONS

Pooled results from all suitable published studies suggest that children born following ART are at increased risk of birth defects compared with spontaneous conceptions. This information should be made available to couples seeking ART treatment.

Imprinting diseases and IVF: Danish National IVF cohort study

BACKGROUND

The aim of this study was to compare the frequency of imprinting diseases in children born after IVF with the incidence in naturally conceived children.

METHODS

All singleton children born in Denmark from January 1, 1995 through December 31, 2001 were stratified into children born without and after IVF, and were followed from birth until the end of 2002 in the National Register of Patients and the Central Register of Psychiatric Diseases, which include all discharge diagnoses from somatic and psychiatric hospitals/clinics, respectively. Included in the study were malignancies, mental, behavioural and neurological diseases, congenital syndromes, and developmental disturbances. Only diagnosis codes potentially relevant for imprinting diseases were included.

RESULTS

During the 7-year study period, 442,349 singleton non-IVF and 6052 IVF children were born. Mean follow-up time was 4.5 and 4.1 years for the two groups, respectively, corresponding to 2 million and 25 000 follow-up years. In the IVF/non-IVF cohort, we detected 0/72 children with cancer, 47/3766 with mental diseases, 72/3654 neurological diseases, 4/287 congenital syndromes and 96/6727 developmental disturbances, in a total of 219/14,506 clinical outcomes. The number of children with specific imprinting diseases in the non-IVF group was 54: 44 kidney cancers, five retinoblastoma, three Prader-Willi syndrome and two Russel-Silver syndrome. Anticipating the same occurrence in IVF children, the total expected number was calculated to be 0.74. The observed number in the IVF group was 0. We found a significantly increased risk of cerebral palsy in the IVF group, with a rate ratio (RR) (IVF:non-IVF) of 1.8 [95% confidence interval (CI) 1.2-2.8; P < 0.01], and of sleeping disturbances, with an RR 2.0 (95% CI 1.2-3.3). The incidence rate of childhood cancers, mental diseases, congenital syndromes and developmental disturbances was equal in the two groups.

CONCLUSIONS

We found no indication of an increased risk of imprinting diseases after IVF, but an 80% increased risk of cerebral palsy. We observed equal frequencies of childhood cancers, mental diseases, congenital syndromes and developmental disturbances in the two groups. Danish register data do not support reports of an increased risk of imprinting diseases after IVF.

Elective single-embryo transfer versus double-embryo transfer in in vitro fertilization

BACKGROUND

The risks of premature birth and perinatal death are increased after in vitro fertilization. These risks are mainly due to the high incidence of multiple births, which relates to the number of embryos transferred.

METHODS

We performed a randomized, multicenter trial to assess the equivalence of two approaches to in vitro fertilization with respect to the rates of pregnancy that result in at least one live birth and to compare associated rates of multiple gestation. Women less than 36 years of age who had at least two good-quality embryos were randomly assigned either to undergo transfer of a single fresh embryo and, if there was no live birth, subsequent transfer of a single frozen-and-thawed embryo, or to undergo a single transfer of two fresh embryos. Equivalence was defined as a difference of no more than 10 percentage points in the rates of pregnancy resulting in at least one live birth.

RESULTS

Pregnancy resulting in at least one live birth occurred in 142 of 331 women (42.9 percent) in the double-embryo-transfer group as compared with 128 of 330 women (38.8 percent) in the single-embryo-transfer group (difference, 4.1 percentage points; 95 percent confidence interval, -3.4 to 11.6 percentage points); rates of multiple births were 33.1 percent and 0.8 percent, respectively (P<0.001). These results do not demonstrate equivalence of the two approaches in rates of live births, but they do indicate that any reduction in the rate of live births with the transfer of single embryos is unlikely to exceed 11.6 percentage points.

CONCLUSIONS

In women under 36 years of age, transferring one fresh embryo and then, if needed, one frozen-and-thawed embryo dramatically reduces the rate of multiple births while achieving a rate of live births that is not substantially lower than the rate that is achievable with a double-embryo transfer.

Increased risk of preterm birth in singleton pregnancies resulting from in vitro fertilization–embryo transfer or gamete intrafallopian transfer: A meta-analysis

OBJECTIVE

To perform a systematic review of the literature to determine whether singleton pregnancies resulting from IVF-ET/GIFT are at higher risk for preterm birth (<37 weeks).

DESIGN

Literature search and systematic review.

SETTING

Medical school.

INTERVENTION(S)

A MEDLINE search (1965-2000) was performed using the terms "premature labor," "infertility," "pregnancy complications," "gonadotropins," "pregnancy outcome," "preterm delivery," and "in vitro fertilization." Criteria for inclusion were English language, original research article, study patients conceived using IVF-ET (with or without intracytoplasmic sperm injection) or GIFT, pregnancy outcome reported compared with a control group (e.g., naturally conceived singletons at their hospital or a national reference), and prematurity clearly defined. Incomplete articles (e.g., abstracts), reports of other studies, and studies that failed to separate multiple from singleton gestations were excluded.

MAIN OUTCOME MEASURE(S)

Summary of relative risks of preterm birth.

RESULT(S)

Twenty-seven articles met all inclusion/exclusion criteria and were analyzed by meta-analysis. The random-effects summary relative risk of preterm birth in singleton pregnancies resulting from IVF-ET/GIFT was 1.98 (95% confidence interval, 1.77-2.22).

CONCLUSION(S)

The risk of preterm birth in singleton pregnancies resulting from IVF-ET/GIFT is twice that of natural conceived pregnancies.

When to avoid creating surplus human embryos

The advice that should be given to a couple considering assisted reproductive technologies for the treatment of their infertility, when they are completely opposed to the destruction of surplus embryos, is discussed. It is urged that they do not use treatments that generate surplus embryos. They should be given the options of declining IVF and considering adoption, or less efficient treatments, namely limited ovarian stimulation, limited insemination of available ova or natural cycle IVF where no surplus embryos are generated.