François Audibert

Prevention of preeclampsia and intrauterine growth restriction with aspirin started in early pregnancy: a meta-analysis.

OBJECTIVE: To estimate the effect of low-dose aspirin started in early pregnancy on the incidence of preeclampsia and intrauterine growth restriction (IUGR). DATA SOURCES: A systematic review and meta-analysis were performed through electronic database searches (PubMed, Cochrane, Embase). METHODS OF STUDY SELECTION: Randomized controlled trials of pregnant women at risk of preeclampsia who were assigned to receive aspirin or placebo (or no treatment) were reviewed. Secondary outcomes included IUGR, severe preeclampsia and preterm birth. The effect of aspirin was analyzed as a function of gestational age at initiation of the intervention (16 weeks of gestation or less, 16 weeks of gestation or more). TABULATION, INTEGRATION, AND RESULTS: Thirty-four randomized controlled trials met the inclusion criteria, including 27 studies (11,348 women) with follow-up for the outcome of preeclampsia. Low-dose aspirin started at 16 weeks or earlier was associated with a significant reduction in preeclampsia (relative risk [RR] 0.47, 95% confidence interval [CI] 0.34–0.65, prevalence in 9.3% treated compared with 21.3% control) and IUGR (RR 0.44, 95% CI 0.30–0.65, 7% treated compared with 16.3% control), whereas aspirin started after 16 weeks was not (preeclampsia: RR 0.81, 95% CI 0.63–1.03, prevalence in 7.3% treated compared with 8.1% control; IUGR: RR 0.98, 95% CI 0.87–1.10, 10.3% treated compared with 10.5% control). Low-dose aspirin started at 16 weeks or earlier also was associated with a reduction in severe preeclampsia (RR 0.09, 95% CI 0.02–0.37, 0.7% treated compared with 15.0% control), gestational hypertension (RR 0.62, 95% CI 0.45–0.84, 16.7% treated compared with 29.7% control), and preterm birth (RR 0.22, 95% CI 0.10–0.49, 3.5% treated compared with 16.9% control). Of note, all studies for which aspirin had been started at 16 weeks or earlier included women identified to be at moderate or high risk for preeclampsia. CONCLUSION: Low-dose aspirin initiated in early pregnancy is an efficient method of reducing the incidence of preeclampsia and IUGR.

Pre-conceptional Vitamin/Folic Acid Supplementation 2007: The Use of Folic Acid in Combination With a Multivitamin Supplement for the Prevention of Neural Tube Defects and Other Congenital Anomalies

OBJECTIVE To provide information regarding the use of folic acid in combination with a multivitamin supplement for the prevention of neural tube defects and other congenital anomalies, so that physicians, midwives, nurses, and other health care workers can assist in the education of women in the pre-conception phase of their health care. OPTION: Supplementation with folic acid and vitamins is problematic, since 50% of pregnancies are unplanned, and womens health status may not be optimal when they conceive. OUTCOMES Folic acid in combination with a multivitamin supplement has been associated with a decrease in specific birth defects. EVIDENCE Medline, PubMed, and Cochrane Database were searched for relevant English language articles published between 1985 and 2007. The previous Society of Obstetricians and Gynaecologists of Canada (SOGC) Policy Statement of November 1993 and statements from the American College of Obstetrics and Gynecology and Canadian College of Medical Geneticists were also reviewed in developing this clinical practice guideline. VALUES The quality of evidence was rated using the criteria described in the Report of the Canadian Task Force on Preventive Health Care. BENEFITS, HARMS, AND COSTS Promoting the use of folic acid and a multivitamin supplement among women of reproductive age will reduce the incidence of birth defects. The costs are those of daily vitamin supplementation and eating a healthy diet. RECOMMENDATIONS 1. Women in the reproductive age group should be advised about the benefits of folic acid in addition to a multivitamin supplement during wellness visits (birth control renewal, Pap testing, yearly examination) especially if pregnancy is contemplated. (III-A) 2. Women should be advised to maintain a healthy diet, as recommended in Eating Well With Canadas Food Guide (Health Canada). Foods containing excellent to good sources of folic acid are fortified grains, spinach, lentils, chick peas, asparagus, broccoli, peas, Brussels sprouts, corn, and oranges. However, it is unlikely that diet alone can provide levels similar to folate-multivitamin supplementation. (III-A) 3. Women taking a multivitamin containing folic acid should be advised not to take more than one daily dose of vitamin supplement, as indicated on the product label. (II-2-A) 4. Folic acid and multivitamin supplements should be widely available without financial or other barriers for women planning pregnancy to ensure the extra level of supplementation. (III-B) 5. Folic acid 5 mg supplementation will not mask vitamin B12 deficiency (pernicious anemia), and investigations (examination or laboratory) are not required prior to initiating supplementation. (II-2-A) 6. The recommended strategy to prevent recurrence of a congenital anomaly (anencephaly, myelomeningocele, meningocele, oral facial cleft, structural heart disease, limb defect, urinary tract anomaly, hydrocephalus) that has been reported to have a decreased incidence following preconception / first trimester folic acid +/- multivitamin oral supplementation is planned pregnancy +/- supplementation compliance. A folate-supplemented diet with additional daily supplementation of multivitamins with 5 mg folic acid should begin at least three months before conception and continue until 10 to 12 weeks post conception. From 12 weeks post-conception and continuing throughout pregnancy and the postpartum period (4-6 weeks or as long as breastfeeding continues), supplementation should consist of a multivitamin with folic acid (0.4-1.0 mg). (I-A) 7. The recommended strategy(ies) for primary prevention or to decrease the incidence of fetal congenital anomalies will include a number of options or treatment approaches depending on patient age, ethnicity, compliance, and genetic congenital anomaly risk status. OPTION A: Patients with no personal health risks, planned pregnancy, and good compliance require a good diet of folate-rich foods and daily supplementation with a multivitamin with folic acid (0.4-1.0 mg) for at least two to three months before conception and throughout pregnancy and the postpartum period (4-6 weeks and as long as breastfeeding continues). (II-2-A) OPTION B: Patients with health risks, including epilepsy, insulin dependent diabetes, obesity with BMI >35 kg/m2, family history of neural tube defect, belonging to a high-risk ethnic group (e.g., Sikh) require increased dietary intake of folate-rich foods and daily supplementation, with multivitamins with 5 mg folic acid, beginning at least three months before conception and continuing until 10 to 12 weeks post conception. From 12 weeks post-conception and continuing throughout pregnancy and the postpartum period (4-6 weeks or as long as breastfeeding continues), supplementation should consist of a multivitamin with folic acid (0.4-1.0 mg). (II-2-A) OPTION C: Patients who have a history of poor compliance with medications and additional lifestyle issues of variable diet, no consistent birth control, and possible teratogenic substance use (alcohol, tobacco, recreational non-prescription drugs) require counselling about the prevention of birth defects and health problems with folic acid and multivitamin supplementation. The higher dose folic acid strategy (5 mg) with multivitamin should be used, as it may obtain a more adequate serum red blood cell folate level with irregular vitamin / folic acid intake but with a minimal additional health risk. (III-B) 8. The Canadian Federal Government could consider an evaluation process for the benefit/risk of increasing the level of national folic acid flour fortification to 300 mg/100 g (present level 140 mg/100 g). (III-B) 9. The Canadian Federal Government could consider an evaluation process for the benefit/risk of additional flour fortification with multivitamins other than folic acid. (III-B) 10. The Society of Obstetricians and Gynaecologists of Canada will explore the possibility of a Canadian Consensus conference on the use of folic acid and multivitamins for the primary prevention of specific congenital anomalies. The conference would include Health Canada/Congenital Anomalies Surveillance, Canadian College of Medical Geneticists, Canadian Paediatric Society, Motherisk, and pharmaceutical industry representatives. VALIDATION This is a revision of a previous guideline and information from other consensus reviews from medical and government publications has been used. SPONSOR The Society of Obstetricians and Gynaecologists of Canada.

Clinical utility of strict diagnostic criteria for the HELLP (hemolysis, elevated liver enzymes, and low platelets) syndrome

OBJECTIVE Our purpose was to compare the maternal outcome of pregnancies complicated by HELLP (hemolysis, elevated liver enzymes, and low platelets) syndrome, partial HELLP syndrome, or severe preeclampsia. STUDY DESIGN In a retrospective cohort study we reviewed the maternal charts of 316 women with HELLP syndrome or severe preeclampsia managed at our perinatal center between July 1, 1992, and June 30, 1995. HELLP syndrome was strictly defined by previously published laboratory criteria. Women were divided into three groups: HELLP syndrome (n = 67), partial HELLP syndrome (one or two but not all three features of HELLP syndrome, n = 71), and severe preeclampsia (no features of HELLP syndrome, n = 178). Results were compared by chi 2 analysis and one-way analysis of variance. RESULTS Mean gestational ages at delivery in the HELLP, partial HELLP, and severe preeclampsia groups were, respectively, 31.7, 32.7, and 34.5 weeks (p < 0.001 between HELLP and severe preeclampsia). There was one maternal death from intracerebral hemorrhage in the HELLP group. In women with HELLP syndrome there was a higher incidence of cesarean section (p < 0.05), disseminated intravascular coagulation (p < 0.001), and need for transfusion (p < 0.001) than in the other two groups. CONCLUSIONS Higher incidences of maternal complications in women with HELLP syndrome stress the importance of strict criteria for the definition of HELLP syndrome. Women with partial HELLP syndrome should be studied and managed separately from women with complete HELLP syndrome.

Obstetrical complications associated with abnormal maternal serum markers analytes.

OBJECTIVE To review the obstetrical outcomes associated with abnormally elevated or decreased level of one or more of the most frequently measured maternal serum marker analytes used in screening for aneuploidy. To provide guidance to facilitate the management of pregnancies that have abnormal levels of one of more markers and to assess the usefulness of these markers as a screening test. OPTIONS Perinatal outcomes associated with abnormal levels of maternal serum markers analytes are compared with the outcomes of pregnancies with normal levels of the same analytes or the general population. EVIDENCE The Cochrane Library and Medline were searched for English-language articles published from 1966 to February 2007, relating to maternal serum markers and perinatal outcomes. Search terms included PAPP-A (pregnancy associated plasma protein A), AFP (alphafetoprotein), hCG (human chorionic gonadotropin), estriol, unconjugated estriol, inhibin, inhibin-A, maternal serum screen, triple marker screen, quadruple screen, integrated prenatal screen, first trimester screen, and combined prenatal screen. All study types were reviewed. Randomized controlled trials were considered evidence of the highest quality, followed by cohort studies. Key individual studies on which the recommendations are based are referenced. Supporting data for each recommendation are summarized with evaluative comments and references. The evidence was evaluated using the guidelines developed by the Canadian Task Force on Preventive Health Care. VALUES The evidence collected was reviewed by the Genetics Committee of the Society of Obstetricians and Gynaecologists of Canada. BENEFITS, HARMS, AND COSTS The benefit expected from this guideline is to facilitate early detection of potential adverse pregnancy outcomes when risks are identified at the time of a maternal serum screen. It will help further stratification of risk and provide options for pregnancy management to minimize the impact of pregnancy complications. The potential harms resulting from such practice are associated with the so called false positive (i.e., uncomplicated pregnancies labelled at increased risk for adverse perinatal outcomes), the potential stress associated with such a label, and the investigations performed for surveillance in this situation. No cost-benefit analysis is available to assess costs and savings associated with this guideline. SUMMARY STATEMENTS: 1. An unexplained level of a maternal serum marker analyte is defined as an abnormal level after confirmation of gestational age by ultrasound and exclusion of maternal, fetal, or placental causes for the abnormal level. (III) 2. Abnormally elevated levels of serum markers are associated with adverse pregnancy outcomes in twin pregnancies, after correction for the number of fetuses. Spontaneous or planned mutifetal reductions may result in abnormal elevations of serum markers. (II-2) RECOMMENDATIONS: 1. In the first trimester, an unexplained low PAPP-A (< 0.4 MoM) and/or a low hCG (< 0.5 MoM) are associated with an increased frequency of adverse obstetrical outcomes, and, at present, no specific protocol for treatment is available. (II-2A) In the second trimester, an unexplained elevation of maternal serum AFP (> 2.5 MoM), hCG (> 3.0 MoM), and/or inhibin-A (> or =2.0 MoM) or a decreased level of maternal serum AFP (< 0.25 MoM) and/or unconjugated estriol (< 0.5 MoM) are associated with an increased frequency of adverse obstetrical outcomes, and, at present, no specific protocol for treatment is available. (II-2A) 2. Pregnant woman with an unexplained elevated PAPP-A or hCG in the first trimester and an unexplained low hCG or inhibin-A and an unexplained elevated unconjugated estriol in the second trimester should receive normal antenatal care, as this pattern of analytes is not associated with adverse perinatal outcomes. (II-2A) 3. The combination of second or third trimester placenta previa and an unexplained elevated maternal serum AFP should increase the index of suspicion for placenta accreta, increta, or percreta. (II-2B) An assessment (ultrasound, MRI) of the placental-uterine interface should be performed. Abnormal invasion should be strongly suspected, and the planning of delivery location and technique should be done accordingly. (III-C) 4. A prenatal consultation with the medical genetics department is recommended for low unconjugated estriol levels (<0.3 MoM), as this analyte pattern can be associated with genetic conditions. (II-2B) 5. The clinical management protocol for identification of potential adverse obstetrical outcomes should be guided by one or more abnormal maternal serum marker analyte value rather than the false positive screening results for the trisomy 21 and/or the trisomy 18 screen. (II-2B) 6. Pregnant woman who are undergoing renal dialysis or who have had a renal transplant should be offered maternal serum screening, but interpretation of the result is difficult as the level of serum hCG is not reliable. (II-2A) 7. Abnormal maternal uterine artery Doppler in association with elevated maternal serum AFP, hCG, or inhibin-A or decreased PAPP-A identifies a group of women at greater risk of IUGR and gestational hypertension with proteinuria. Uterine artery Doppler measurements may be used in the evaluation of an unexplained abnormal level of either of these markers. (II-2B) 8. Further research is recommended to identify the best protocol for pregnancy management and surveillance in women identified at increased risk of adverse pregnancy outcomes based on an abnormality of a maternal serum screening analyte. (III-A) 9. In the absence of evidence supporting any specific surveillance protocol, an obstetrician should be consulted in order to establish a fetal surveillance plan specific to the increased obstetrical risks (maternal and fetal) identified. This plan may include enhanced patient education on signs and symptoms of the most common complications, increased frequency of antenatal visits, increased ultrasound (fetal growth, amniotic fluid levels), and fetal surveillance (biophysical profile, arterial and venous Doppler), and cervical length assessment. (III-A) 10. Limited information suggests that, in women with elevated hCG in the second trimester and/or abnormal uterine artery Doppler (at 22-24 weeks), low-dose aspirin (60-81 mg daily) is associated with higher birthweight and lower incidence of gestational hypertension with proteinuria. This therapy may be used in women who are at risk. (II-2B) 11. Further studies are recommended in order to assess the benefits of low-dose aspirin, low molecular weight heparin, or other therapeutic options in pregnancies determined to be at increased risk on the basis of an abnormal maternal serum screening analyte. (III-A) 12. Multiple maternal serum markers screening should not be used at present as a population-based screening method for adverse pregnancy outcomes (such as preeclampsia, placental abruption, and stillbirth) outside an established research protocol, as sensitivity is low, false positive rates are high, and no management protocol has been shown to clearly improve outcomes. (II-2D) When maternal serum screening is performed for the usual clinical indication (fetal aneuploidy and/or neural tube defect), abnormal analyte results can be utilized for the identification of pregnancies at risk and to direct their clinical management. (II-2B) Further studies are recommended to determine the optimal screening method for poor maternal and/or perinatal outcomes. (III-A).

Mycophenolate mofetil in pregnancy after renal transplantation: a case of major fetal malformations.

BACKGROUND: Mycophenolate mofetil has teratogenic properties in rats and rabbits. Previous human studies have reported an increased rate of fetal losses with its use. We report a case of major fetal malformations due to mycophenolate mofetil. CASE: The patient was treated with mycophenolate mofetil before conception and during the first trimester of pregnancy. The fetus had multiple malformations, specifically, facial dysmorphology and midline anomalies, including agenesis of the corpus callosum. CONCLUSION: This case of fetal malformation attributable to mycophenolate mofetil must be taken into consideration when considering pregnancy in an organ-transplant recipient.

Screening for preeclampsia using first-trimester serum markers and uterine artery Doppler in nulliparous women

OBJECTIVE To evaluate the screening accuracy of pregnancy hypertensive disorders by maternal serum biomarkers and uterine artery Doppler in the first trimester. STUDY DESIGN Prospectively enrolled nulliparous women had uterine artery Doppler and serum measured at 11-13 weeks. Maternal characteristics, uterine artery Doppler, and serum placental biomarkers (pregnancy-associated plasma protein-A, Inhibin-A, placental protein 13, A disintegrin and metalloprotease 12, free β-hCG, placental growth factor) were recorded. RESULTS Among 893 women, 20 (2.2%) had gestational hypertension developed and 40 (4.5%) had preeclampsia developed, including 9 (1.0%) early-onset preeclampsia and 16 (1.8%) severe preeclampsia. A combined screening model with clinical characteristics, pregnancy-associated plasma protein-A, Inhibin-A, and placental growth factor could detect 75% of early-onset preeclampsia at a 10% false-positive rate. After adjustment for clinical variables, uterine artery Doppler, placental protein 13, and A disintegrin and metalloprotease 12 did not improve the diagnostic accuracy. CONCLUSION A combination of clinical characteristics and first-trimester maternal serum biomarkers (pregnancy-associated plasma protein-A, Inhibin-A, and placental growth factor) provides an accurate screening for early-onset preeclampsia in nulliparous women.

Delayed Child-Bearing

OBJECTIVE To provide an overview of delayed child-bearing and to describe the implications for women and health care providers. OPTIONS Delayed child-bearing, which has increased greatly in recent decades, is associated with an increased risk of infertility, pregnancy complications, and adverse pregnancy outcome. This guideline provides information that will optimize the counselling and care of Canadian women with respect to their reproductive choices. OUTCOMES Maternal age is the most important determinant of fertility, and obstetric and perinatal risks increase with maternal age. Many women are unaware of the success rates or limitations of assisted reproductive technology and of the increased medical risks of delayed child-bearing, including multiple births, preterm delivery, stillbirth, and Caesarean section. This guideline provides a framework to address these issues. EVIDENCE Studies published between 2000 and August 2010 were retrieved through searches of PubMed and the Cochrane Library using appropriate key words (delayed child-bearing, deferred pregnancy, maternal age, assisted reproductive technology, infertility, and multiple births) and MeSH terms (maternal age, reproductive behaviour, fertility). The Internet was also searched using similar key words, and national and international medical specialty societies were searched for clinical practice guidelines and position statements. Data were extracted based on the aims, sample, authors, year, and results. VALUES The quality of evidence was rated using the criteria described in the Report of the Canadian Task Force on Preventive Health Care (Table 1). SPONSOR The Society of Obstetricians and Gynaecologists of Canada. RECOMMENDATIONS 1. Women who delay child-bearing are at increased risk of infertility. Prospective parents, especially women, should know that their fecundity and fertility begin to decline significantly after 32 years of age. Prospective parents should know that assisted reproductive technologies cannot guarantee a live birth or completely compensate for age-related decline in fertility. (II-2A) 2. A fertility evaluation should be initiated after 6 months of unprotected intercourse without conception in women 35 to 37 years of age, and earlier in women > 37 years of age. (II-2A) 3. Prospective parents should be informed that semen quality and male fertility deteriorate with advancing age and that the risk of genetic disorders in offspring increases. (II-2A) 4. Women ≥ 35 years of age should be offered screening for fetal aneuploidy and undergo a detailed second trimester ultrasound examination to look for significant fetal birth defects (particularly cardiac defects). (II-1A) 5. Delayed child-bearing is associated with increased obstetrical and perinatal complications. Care providers need to be aware of these complications and adjust obstetrical management protocols to ensure optimal maternal and perinatal outcomes. (II-2A) 6. All adults of reproductive age should be aware of the obstetrical and perinatal risks of advanced maternal age so they can make informed decisions about the timing of child-bearing. (II-2A) 7. Strategies to improve informed decision-making by prospective parents should be designed, implemented, and evaluated. These strategies should provide opportunity for adults to understand the potential medical, social, and economic consequences of child-bearing throughout the reproductive years. (III-B) 8. Barriers to healthy reproduction, including workplace policies, should be reviewed to optimize the likelihood of healthy pregnancies. (III-C).

An international trial of antioxidants in the prevention of preeclampsia (INTAPP).

OBJECTIVE We sought to investigate whether prenatal vitamin C and E supplementation reduces the incidence of gestational hypertension (GH) and its adverse conditions among high- and low-risk women. STUDY DESIGN In a multicenter randomized controlled trial, women were stratified by the risk status and assigned to daily treatment (1 g vitamin C and 400 IU vitamin E) or placebo. The primary outcome was GH and its adverse conditions. RESULTS Of the 2647 women randomized, 2363 were included in the analysis. There was no difference in the risk of GH and its adverse conditions between groups (relative risk, 0.99; 95% confidence interval, 0.78-1.26). However, vitamins C and E increased the risk of fetal loss or perinatal death (nonprespecified) as well as preterm prelabor rupture of membranes. CONCLUSION Vitamin C and E supplementation did not reduce the rate of preeclampsia or GH, but increased the risk of fetal loss or perinatal death and preterm prelabor rupture of membranes.

The relationships between antenatal management, the cause of delivery and neonatal outcome in a large cohort of very preterm singleton infants.

Objective To determine whether the cause of very preterm delivery influences neonatal outcome.

Prenatal Screening for Fetal Aneuploidy in Singleton Pregnancies

OBJECTIVE To develop a Canadian consensus document on maternal screening for fetal aneuploidy (e.g., Down syndrome and trisomy 18) in singleton pregnancies. OPTIONS Pregnancy screening for fetal aneuploidy started in the mid 1960s, using maternal age as the screening test. New developments in maternal serum and ultrasound screening have made it possible to offer all pregnant patients a non-invasive screening test to assess their risk of having a fetus with aneuploidy to determine whether invasive prenatal diagnostic testing is necessary. This document reviews the options available for non-invasive screening and makes recommendations for Canadian patients and health care workers. OUTCOMES To offer non-invasive screening for fetal aneuploidy (trisomy 13, 18, 21) to all pregnant women. Invasive prenatal diagnosis would be offered to women who screen above a set risk cut-off level on non-invasive screening or to pregnant women whose personal, obstetrical, or family history places them at increased risk. Currently available non-invasive screening options include maternal age combined with one of the following: (1) first trimester screening (nuchal translucency, maternal age, and maternal serum biochemical markers), (2) second trimester serum screening (maternal age and maternal serum biochemical markers), or (3) 2-step integrated screening, which includes first and second trimester serum screening with or without nuchal translucency (integrated prenatal screen, serum integrated prenatal screening, contingent, and sequential). These options are reviewed, and recommendations are made. EVIDENCE Studies published between 1982 and 2009 were retrieved through searches of PubMed or Medline and CINAHL and the Cochrane Library, using appropriate controlled vocabulary and key words (aneuploidy, Down syndrome, trisomy, prenatal screening, genetic health risk, genetic health surveillance, prenatal diagnosis). Results were restricted to systematic reviews, randomized controlled trials, and relevant observational studies. There were no language restrictions. Searches were updated on a regular basis and incorporated in the guideline to August 2010. Grey (unpublished) literature was identified through searching the websites of health technology assessment and health technology assessment-related agencies, clinical practice guideline collections, clinical trial registries, and national and international medical specialty societies. The previous Society of Obstetricians and Gynaecologists of Canada guidelines regarding prenatal screening were also reviewed in developing this clinical practice guideline. VALUES The quality of evidence was rated using the criteria described in the Report of the Canadian Task Force on Preventive Health Care. BENEFITS, HARMS, AND COSTS This guideline is intended to reduce the number of prenatal invasive procedures done when maternal age is the only indication. This will have the benefit of reducing the numbers of normal pregnancies lost because of complications of invasive procedures. Any screening test has an inherent false-positive rate, which may result in undue anxiety. It is not possible at this time to undertake a detailed cost-benefit analysis of the implementation of this guideline, since this would require health surveillance and research and health resources not presently available; however, these factors need to be evaluated in a prospective approach by provincial and territorial initiatives. RECOMMENDATIONS 1. All pregnant women in Canada, regardless of age, should be offered, through an informed counselling process, the option of a prenatal screening test for the most common clinically significant fetal aneuploidies in addition to a second trimester ultrasound for dating, assessment of fetal anatomy, and detection of multiples. (I-A) 2. Counselling must be non-directive and must respect a womans right to accept or decline any or all of the testing or options offered at any point in the process. (III-A) 3. Maternal age alone is a poor minimum standard for prenatal screening for aneuploidy, and it should not be used a basis for recommending invasive testing when non-invasive prenatal screening for aneuploidy is available. (II-2A) 4. Invasive prenatal diagnosis for cytogenetic analysis should not be performed without multiple marker screening results except for women who are at increased risk of fetal aneuploidy (a) because of ultrasound findings, (b) because the pregnancy was conceived by in vitro fertilization with intracytoplasmic sperm injection, or (c) because the woman or her partner has a history of a previous child or fetus with a chromosomal abnormality or is a carrier of a chromosome rearrangement that increases the risk of having a fetus with a chromosomal abnormality. (II-2E) 5. At minimum, any prenatal screen offered to Canadian women who present for care in the first trimester should have a detection rate of 75% with no more than a 3% false-positive rate. The performance of the screen should be substantiated by annual audit. (III-B) 6. The minimum standard for women presenting in the second trimester should be a screen that has a detection rate of 75% with no more than a 5% false-positive rate. The performance of the screen should be substantiated by annual audit. (III-B) 7. First trimester nuchal translucency should be interpreted for risk assessment only when measured by sonographers or sonologists trained and accredited for this service and when there is ongoing quality assurance (II-2A), and it should not be offered as a screen without biochemical markers in singleton pregnancies. (I-E) 8. Evaluation of the fetal nasal bone in the first trimester should not be incorporated as a screen unless it is performed by sonographers or sonologists trained and accredited for this service and there is ongoing quality assurance. (II-2E) 9. For women who undertake first trimester screening, second trimester serum alpha fetoprotein screening and/or ultrasound examination is recommended to screen for open neural tube defects. (II-1A) 10. Timely referral and access is critical for women and should be facilitated to ensure women are able to undergo the type of screening test they have chosen as first trimester screening. The first steps of integrated screening (with or without nuchal translucency), contingent, or sequential screening are performed in an early and relatively narrow time window. (II-1A) 11. Ultrasound dating should be performed if menstrual or conception dating is unreliable. For any abnormal serum screen calculated on the basis of menstrual dating, an ultrasound should be done to confirm gestational age. (II-1A) 12. The presence or absence of soft markers or anomalies in the 18- to 20-week ultrasound can be used to modify the a priori risk of aneuploidy established by age or prior screening. (II-2B) 13. Information such as gestational dating, maternal weight, ethnicity, insulin-dependent diabetes mellitus, and use of assisted reproduction technologies should be provided to the laboratory to improve accuracy of testing. (II-2A) 14. Health care providers should be aware of the screening modalities available in their province or territory. (III-B) 15. A reliable system needs to be in place ensuring timely reporting of results. (III-C) 16. Screening programs should be implemented with resources that support audited screening and diagnostic laboratory services, ultrasound, genetic counselling services, patient and health care provider education, and high quality diagnostic testing, as well as resources for administration, annual clinical audit, and data management. In addition, there must be the flexibility and funding to adjust the program to new technology and protocols. (II-3B).