To review the effect of assisted reproductive technology (ART) on perinatal outcomes, to provide guidelines to optimize obstetrical management and counselling of Canadian women using ART, and to identify areas specific to birth outcomes and ART requiring further research.
This guideline discusses the adverse outcomes that have been recorded in association with ART, including obstetrical complications, adverse perinatal outcomes, multiple gestations, structural congenital abnormalities, chromosomal abnormalities, imprinting disorders, and childhood cancer.
The Cochrane Library and MEDLINE were searched for English-language articles from 1990 to February 2005, relating to assisted reproduction and perinatal outcomes. Search terms included assisted reproduction, assisted reproductive technology, ovulation induction, intracytoplasmic sperm injection (ICSI), embryo transfer, and in vitro fertilization (IVF). Additional publications were identified from the bibliographies of these articles as well as the Science Citation Index. Studies assessing gamete intrafallopian transfer (GIFT) and zygote intrafallopian transfer (ZIFT) were excluded since they are rarely used in Canada. All study types were reviewed. Randomized controlled trials were considered evidence of the highest quality, followed by cohort studies. Key studies and supporting data for each recommendation are summarized with evaluative comments and referenced.
The evidence collected was reviewed by the Genetics Committee and the Reproductive Endocrinology Infertility Committee of the Society of Obstetricians and Gynaecologists of Canada (SOGC) and quantified using the Evaluation of Evidence Guidelines developed by the Canadian Task Force on the Periodic Health Examination.
The type and magnitude of benefits, harms, and costs expected for patients from guideline implementation. This guideline has been reviewed by the Genetics Committee and the Reproductive Endocrinology and Infertility Committee, and approved by the Executive and Council of the Society of Obstetricians and Gynaecologists of Canada and the Board of the Canadian Fertility and Andrology Society.
1. Spontaneous pregnancies in untreated infertile women may be at higher risk for obstetrical complications and perinatal mortality than spontaneous pregnancies in fertile women. Further research is required to clarify the contribution of infertility itself to adverse obstetrical and perinatal outcomes. (II-2A) 2. All men with severe oligozoospermia or azoospermia should be offered genetic/clinical counselling for informed consent and offered karyotyping for chromosomal abnormalities before attempting IVF-ICSI. They should be made aware of the availability of tests for Y chromosome microdeletion. Some patients may consider the option of donor insemination. (II-3B) 3. Couples exploring IVF-ICSI when the man has obstructive azoospermia should be offered genetic/clinical counselling for informed consent and offered genetic testing for alterations in genes associated with cystic fibrosis (CF) before attempting IVF-ICSI. (II-2A) 4. Pregnancies achieved by ovarian stimulation with gonadotropins and intrauterine insemination are at higher risk for perinatal complications, and close surveillance during pregnancy should be considered. It remains unclear if these increased risks are attributable to the underlying infertility, characteristics of the infertile couple, or use of assisted reproductive techniques. Multiple gestations remain a significant risk of gonadotropin treatment. (II-2A) 5. Pregnancies achieved by IVF with or without ICSI are at higher risk for obstetrical and perinatal complications than spontaneous pregnancies, and close surveillance during pregnancy should be considered. It remains unclear if these increased risks are attributable to the underlying infertility, characteristics of the infertile couple, or use of assisted reproductive techniques. (II-2A) 6. Women undergoing ART should be informed about the increased rate of obstetrical interventions such as induced labour and elective Caesarean delivery. (II-2A) 7. Couples suffering from infertility who are exploring treatment options should be made aware of the psychosocial implications of ART. Further research into the psychosocial impact of ART is needed. (II-2A) 8. Singleton pregnancies achieved by assisted reproduction are at higher risk than spontaneous pregnancies for adverse perinatal outcomes, including perinatal mortality, preterm delivery, and low birth weight, and close surveillance during pregnancy should be available as needed. (II-2A) 9. A significant risk of ART is multiple pregnancies. Infertile couples need to be informed of the increased risks of multifetal pregnancies. Although dichorionic twins are most common, the incidence of monochorionic twins is also increased. Risks of multiple pregnancies include higher rates of perinatal mortality, preterm birth, low birth weight, gestational hypertension, placental abruption, and placenta previa. Perinatal mortality in assisted conception twin pregnancies appears to be lower than in spontaneously conceived twin pregnancies. (II-2A) 10. When multifetal reduction is being considered for high-order multiple pregnancies, psychosocial counselling should be readily available. Careful surveillance for fetal growth problems should be undertaken after multifetal reduction. (II-2A) 11. To reduce the risks of multiple pregnancies associated with ART and to optimize pregnancy rates, national guidelines should be developed on the number of embryos replaced according to characteristics such as patient's age and grade of embryos. (II-2A) 12. Further epidemiologic and basic science research is needed to help determine the etiology and extent of the increased risks to childhood and long-term growth and development associated with ART. (II-2A) 13. Discussion of options for prenatal screening for congenital structural abnormalities in pregnancies achieved by ART is recommended, including appropriate use of biochemical and sonographic screening. (II-2A) 14. Further epidemiologic and basic science research is needed to help determine the etiology and extent of the increased risks of congenital abnormalities associated with ART. (II-2A) 15. Couples considering IVF-ICSI for male-factor infertility should receive information, and if necessary formal genetic counselling, about the increased risk of de novo chromosomal abnormalities (mainly sex chromosomal anomalies) associated with their condition. Prenatal diagnosis by chorionic villus sampling (CVS) or amniocentesis should be offered to these couples if they conceive. (II-2A) 16. Further epidemiologic and basic science research is needed to help determine the etiology and extent of the increased risks of chromosomal abnormalities associated with ART. (II-2A) 17. Discussion of options for prenatal screening and testing for aneuploidy in pregnancies achieved by ART, adapted for maternal age and number of fetuses, is recommended, including appropriate use of biochemical and sonographic screening. (II-2A) 18. The precise risks of imprinting and childhood cancer from ART remain unclear but cannot be ignored. Further clinical research, including long-term follow-up, is urgently required to evaluate the prevalence of imprinting disorders and cancers associated with ART. (II-2A) 19. The clinical application of preimplantation genetic diagnosis must balance the benefits of avoiding disease transmission with the medical risks and financial burden of in vitro fertilization. Further ethical discussion and clinical research is required to evaluate appropriate indications for preimplantation genetic diagnosis. (III-B).