First-trimester screening for trisomies 21 and 18.

BACKGROUND: Screening for aneuploid pregnancies is routinely performed after 15 weeks of gestation and has a sensitivity of approximately 65 percent, with a false positive rate of 5 percent. First-trimester markers of aneuploidy have been developed, but their use in combination has not been adequately evaluated in clinical practice. METHODS: We conducted a multicenter study of screening for trisomies 21 and 18 among patients with pregnancies between 74 and 97 days of gestation, based on maternal age, maternal levels of free beta human chorionic gonadotropin and pregnancy-associated plasma protein A, and ultrasonographic measurement of fetal nuchal translucency. A screening result was considered to be positive for trisomy 21 if the calculated risk was at least 1 in 270 pregnancies and positive for trisomy 18 if the risk was at least 1 in 150. RESULTS: Screening was completed in 8514 patients with singleton pregnancies. This approach to screening identified 85.2 percent of the 61 cases of Down's syndrome (95 percent confidence interval, 73.8 to 93.0), with a false positive rate of 9.4 percent (95 percent confidence interval, 8.8 to 10.1). At a false positive rate of 5 percent, the detection rate was 78.7 percent (95 percent confidence interval, 66.3 to 88.1). Screening identified 90.9 percent of the 11 cases of trisomy 18 (95 percent confidence interval, 58.7 to 99.8), with a 2 percent false positive rate. Among women 35 years of age or older, screening identified 89.8 percent of fetuses with trisomy 21, with a false positive rate of 15.2 percent, and 100 percent of fetuses with trisomy 18. CONCLUSIONS: First-trimester screening for trisomies 21 and 18 on the basis of maternal age, maternal levels of free beta human chorionic gonadotropin and pregnancy-associated plasma protein A, and measurement of fetal nuchal translucency has good sensitivity at an acceptable false positive rate.

Late first-trimester placental disruption and subsequent gestational hypertension/preeclampsia.

OBJECTIVE: To evaluate the potential relationship between placental disruption in weeks 13 and 14 and the subsequent development of gestational hypertension or preeclampsia. METHODS: Using subjects recruited during a randomized trial funded by the National Institute of Child Health and Human Development, which compared early amniocentesis and late transabdominal chorionic villus sampling (CVS) in weeks 13 and 14, rates of gestational hypertension and preeclampsia were compared between cases with varying degrees of placental disruption. RESULTS: A total of 3,698 of 3,775 randomized subjects had cytogenetically normal pregnancies and were analyzed. A significantly higher rate of hypertension/preeclampsia was observed in the late CVS group (5.4%, n = 1,878) compared with the early amniocentesis cohort (3.5%, n = 1,820; P = .005). This difference persisted after controlling for maternal age, body mass index, parity, previous preterm delivery, smoking, and fetal gender. Early amniocentesis cases were further stratified on the basis of whether the placenta had been penetrated (n = 460) or not (n = 1,360). Risk of hypertensive complications was lowest if the placenta was not traversed (3.4%), greater with placental penetration (3.9%), and highest when the placenta was directly sampled during CVS (5.4%, P = .02). CONCLUSION: We hypothesize that focal disruption of the placenta at 13-14 weeks may increase the risk of hypertension/preeclampsia. These findings provide support for the theory that disturbances in early placentation lead subsequently to maternal hypertension.

Sequential pathways of testing after first-trimester screening for trisomy 21.

OBJECTIVE: To evaluate the performance and use of second-trimester multiple-marker maternal serum screening for trisomy 21 by women who had previously undergone first-trimester combined screening (nuchal translucency, pregnancy-associated plasma protein A, and free beta-hCG), with disclosure of risk estimates. METHODS: In a multicenter, first-trimester screening study sponsored by the National Institute of Child Health and Human Development, multiple-marker maternal serum screening with alpha-fetoprotein, unconjugated estriol, and total hCG was performed in 4,145 (7 with trisomy 21) of 7,392 (9 with trisomy 21) women who were first-trimester screen-negative and 180 (7 with trisomy 21) of 813 (52 with trisomy 21) who were first-trimester screen-positive. Second-trimester risks were calculated using multiples of the median and a standardized risk algorithm with a cutoff risk of 1:270. RESULTS: Among the first-trimester screen-negative cohort, 6 of 7 (86%) trisomy 21 cases were detected by second-trimester multiple-marker maternal serum screening with a false-positive rate of 8.9%. Among the first-trimester screen-positive cohort, all 7 trisomy 21 cases were also detected in the second trimester, albeit with a 38.7% false-positive rate. CONCLUSION: Our data demonstrate that a sequential screening program that provides patients with first-trimester results and offers the option for early invasive testing or additional serum screening in the second trimester can detect 98% of trisomy 21-affected pregnancies. However, such an approach will result in 17% of patients being considered at risk and, hence, potentially having an invasive test. LEVEL OF EVIDENCE: II-2

Health-related quality-of-life assessment of prenatal diagnosis: chorionic villi sampling and amniocentesis.

This study assesses the health-related quality-of-life (HRQL) effects of chorionic villi sampling (CVS) and genetic amniocentesis (GA), including both process and outcomes of prenatal diagnosis. The HRQL of 126 women participating in a randomized controlled clinical trial of CVS versus GA in Toronto and Hamilton, Ontario, was assessed in four interviews at weeks 8, 13, 18, and 22 of pregnancy. Statistical analyses included analysis of variance, repeated measures analysis of covariance, chi-square, Fisher's exact test, Student's t-tests, and paired t-tests. Utility scores for patients undergoing CVS exceeded those for GA patients at week 18 (p = 0.04). Utility scores for hypothetical health states did not differ significantly by trial arm. CVS results in slightly improved HRQL during prenatal diagnosis. This advantage needs to be weighed against the high disutility patients attach to infrequent outcomes associated with pregnancy losses, equivocal diagnoses, and diagnostic inaccuracy.

Medical management of a cervical pregnancy: a case report.

BACKGROUND: Cervical pregnancy is a rare condition that can become life-threatening if heavy bleeding occurs. CASE: Grace (pseudonym) is a 32-year-old woman who was admitted to hospital at approximately 6 weeks' gestational age after several days of heavy bleeding. Ultrasonographic examination revealed the presence of cervical pregnancy. She received multiple doses of methotrexate with folinic acid rescue, and did not require surgical intervention. Nine months after the resolution of the cervical pregnancy, Grace again became pregnant. She had an uncomplicated gestation and a normal vaginal delivery of a healthy baby at term. CONCLUSION: Multiple-dose methotrexate with folinic acid rescue was a safe option for the medical treatment of ectopic cervical pregnancy in this case. Long-term toxicity studies and case reports are required to provide more information regarding safety and for clinicians to individualize treatment regimens.

Prospective cohort study of three- versus two-dimensional ultrasound for prediction of oocyte maturity.

OBJECTIVE: To determine whether three-dimensional follicular ultrasound (3-D) measurements are better predictors of optimal timing of hCG administration than two-dimensional (2-D) images, the current standard. DESIGN: Prospective, cohort study. SETTING: Tertiary referral center. PATIENT(S): Seventy-six patients undergoing IVF. INTERVENTION(S): Seventy-six consecutive patients undergoing serial follicular monitoring during IVF had an additional daily 3-D volume scan of their ovaries once lead follicles had reached 16 mm diameter. MAIN OUTCOME MEASURE(S): Number of mature oocytes retrieved. RESULT(S): The 2-D follicular diameter measurements predicted 25.4% of the observed variance in the number of mature oocytes retrieved. The 3-D follicular volume measurements were more predictive of outcome, accounting for 29.2% of the observed variance in number of mature oocytes retrieved. Follicles >22 mm diameter and 5 mL volume were associated with fewer mature oocytes reflecting an undesired postmature state. Follicles measuring 11 to 15 mm had a 50% chance of yielding a mature oocyte. CONCLUSION(S): Three-dimensional follicular volume measurements have a stronger correlation with the number of mature oocytes retrieved than 2-D measurements. As 3-D technology improves, this parameter may replace 2-D measurements in the optimal timing of hCG before oocyte retrieval.

Core binding factor beta (CBFB) haploinsufficiency due to an interstitial deletion at 16q21q22 resulting in delayed cranial ossification, cleft palate, congenital heart anomalies, and feeding difficulties but favorable outcome.

The core binding factor beta gene (CBFB), essential to bone morphogenesis, is located at 16q22.1. Homozygous deficiency of CBFB leads to ossification defects in mice. CBFB forms a heterodimer with RUNX2 (CBFA1) during embryonic bone development. RUNX2 mutations lead to cleidocranial dysplasia in humans. We describe an infant boy with an interstitial deletion of 16q21q22, delayed skull ossification, cleft palate, and heart anomalies who had a difficult course in infancy but eventually improved and is healthy. He was found to have CBFB haploinsufficiency, but did not have mutations in RUNX2. We suggest that 16q21q22 deletion be considered when there are antenatal or postnatal findings of enlarged cranial sutures with or without cleft palate. The finding of CBFB haploinsufficiency in our case and the similarity of cranial ossification defects with a mouse model of CBFB deletion suggest a role for CBFB in cranial bone development in humans.

Association of extreme first-trimester free human chorionic gonadotropin-beta, pregnancy-associated plasma protein A, and nuchal translucency with intrauterine growth restriction and other adverse pregnancy outcomes.

OBJECTIVE: The purpose of this study was to determine the association between first-trimester trisomy 21 screening markers (free human chorionic gonadotropin-beta [hCG], pregnancy-associated plasma protein A [PAPP-A], and nuchal translucency) and adverse pregnancy outcome. STUDY DESIGN: This was a cohort study of 8012 patients enrolled in a National Institute of Child Health and Human Development-sponsored study of first-trimester trisomy 21 and 18 screening. Trisomy 21 and 18 risk results and individual marker levels in unaffected pregnancies and pregnancies with adverse outcomes were evaluated. RESULTS: PAPP-A <1st percentile (OR 5.4, 95% CI 2.8-10.3) and PAPP-A <5th percentile (OR 2.7, 95% CI 1.9-3.9) and free beta-hCG <1st percentile (OR 2.7, 95% CI 1.3-5.9) were associated with increased risk of intrauterine growth restriction (IUGR) with positive predictive values of 24.1%, 14.1%, and 14.3%, respectively. PAPP-A <5th percentile (OR 2.3 95% CI 1.1-4.7) and nuchal translucency >99th percentile (OR 3.5, 95% CI 1.1-11.3) were associated with increased risk of preterm delivery before 34 weeks. Increased risk at screening for trisomy 21 and 18 identified 16 of the 29 other chromosomal abnormalities (55%). Low free beta-hCG, low PAPP-A, and increased nuchal translucency were all associated with an increased rate of fetal abnormality. CONCLUSION: Extreme values of first-trimester free beta-hCG, PAPP-A, and nuchal translucency are all associated with adverse outcomes. The especially high predictive value for IUGR of PAPP-A levels below the 1st percentile suggests that patients within this group may benefit from increased surveillance for this condition.