Analysis of the size distributions of fetal and maternal cell-free DNA by paired-end sequencing.

BACKGROUND: Noninvasive prenatal diagnosis with cell-free DNA in maternal plasma is challenging because only a small portion of the DNA sample is derived from the fetus. A few previous studies provided size-range estimates of maternal and fetal DNA, but direct measurement of the size distributions is difficult because of the small quantity of cell-free DNA. METHODS: We used high-throughput paired-end sequencing to directly measure the size distributions of maternal and fetal DNA in cell-free maternal plasma collected from 3 typical diploid and 4 aneuploid male pregnancies. As a control, restriction fragments of lambda DNA were also sequenced. RESULTS: Cell-free DNA had a dominant peak at approximately 162 bp and a minor peak at approximately 340 bp. Chromosome Y sequences were rarely longer than 250 bp but were present in sizes of <150 bp at a larger proportion compared with the rest of the sequences. Selective analysis of the shortest fragments generally increased the fetal DNA fraction but did not necessarily increase the sensitivity of aneuploidy detection, owing to the reduction in the number of DNA molecules being counted. Restriction fragments of lambda DNA with sizes between 60 bp and 120 bp were preferentially sequenced, indicating that the shotgun sequencing work flow introduced a bias toward shorter fragments. CONCLUSIONS: Our results confirm that fetal DNA is shorter than maternal DNA. The enrichment of fetal DNA by size selection, however, may not provide a dramatic increase in sensitivity for assays that rely on length measurement in situ because of a trade-off between the fetal DNA fraction and the number of molecules being counted.

Maintenance nifedipine tocolysis compared with placebo: a randomized controlled trial.

OBJECTIVE: To estimate whether maintenance nifedipine tocolysis after arrested preterm labor prolongs pregnancy and improves neonatal outcomes. METHODS: A prospective, randomized double-blind, multicenter study was conducted. After successful tocolysis, patients were randomly assigned to receive 20 mg nifedipine or an identical-appearing placebo every 4-6 hours until 37 weeks of gestation. The primary outcome was attainment of 37 weeks of gestation. Patients were enrolled between 24 weeks and 34 weeks if they had six or fewer contractions per hour, intact membranes, and less than 4 cm cervical dilation. Exclusion criteria were placental abruption or previa, fetal anomaly incompatible with life, or maternal medical contraindication to tocolysis. Sixty-six patients were required for 80% power to detect a 50% reduction in birth before 37 weeks, with a two-tailed alpha of 0.05. Data were analyzed by intent to treat. RESULTS: Seventy-one patients were randomly assigned. Two patients were excluded after randomization and one was lost to follow-up. Thirty-five patients received placebo, and 33 received nifedipine. There were no maternal demographic differences between groups; the placebo group was significantly more dilated and effaced at study entry. There was no difference in attainment of 37 weeks (39% nifedipine compared with 37% placebo, P>.91), mean delay of delivery (33.5+/-19.9 days nifedipine compared with 32.6+/-21.4 days placebo, P=.81) or delay of delivery for greater than 48 hours or 1, 2, 3, or 4 weeks. Neonatal outcomes were similar between groups. CONCLUSION: When compared with placebo, maintenance nifedipine tocolysis did not confer a large reduction in preterm birth or improvement in neonatal outcomes. CLINICAL TRIAL REGISTRATION: ClinicalTrials.gov, www.clinicaltrials.gov, NCT00185952 LEVEL OF EVIDENCE: I.

Noninvasive diagnosis of fetal aneuploidy by shotgun sequencing DNA from maternal blood.

We directly sequenced cell-free DNA with high-throughput shotgun sequencing technology from plasma of pregnant women, obtaining, on average, 5 million sequence tags per patient sample. This enabled us to measure the over- and underrepresentation of chromosomes from an aneuploid fetus. The sequencing approach is polymorphism-independent and therefore universally applicable for the noninvasive detection of fetal aneuploidy. Using this method, we successfully identified all nine cases of trisomy 21 (Down syndrome), two cases of trisomy 18 (Edward syndrome), and one case of trisomy 13 (Patau syndrome) in a cohort of 18 normal and aneuploid pregnancies; trisomy was detected at gestational ages as early as the 14th week. Direct sequencing also allowed us to study the characteristics of cell-free plasma DNA, and we found evidence that this DNA is enriched for sequences from nucleosomes.

Prenatal diagnosis of placenta accreta: sonography or magnetic resonance imaging?

OBJECTIVE: The purpose of this study was to compare the accuracy of transabdominal sonography and magnetic resonance imaging (MRI) for prenatal diagnosis of placenta accreta. METHODS: A historical cohort study was undertaken at 3 institutions identifying women at risk for placenta accreta who had undergone both sonography and MRI prenatally. Sonographic and MRI findings were compared with the final diagnosis as determined at delivery and by pathologic examination. RESULTS: Thirty-two patients who had both sonography and MRI prenatally to evaluate for placenta accreta were identified. Of these, 15 had confirmation of placenta accreta at delivery. Sonography correctly identified the presence of placenta accreta in 14 of 15 patients (93% sensitivity; 95% confidence interval [CI], 80%-100%) and the absence of placenta accreta in 12 of 17 patients (71% specificity; 95% CI, 49%-93%). Magnetic resonance imaging correctly identified the presence of placenta accreta in 12 of 15 patients (80% sensitivity; 95% CI, 60%-100%) and the absence of placenta accreta in 11 of 17 patients (65% specificity; 95% CI, 42%-88%). In 7 of 32 cases, sonography and MRI had discordant diagnoses: sonography was correct in 5 cases, and MRI was correct in 2. There was no statistical difference in sensitivity (P = .25) or specificity (P = .5) between sonography and MRI. CONCLUSIONS: Both sonography and MRI have fairly good sensitivity for prenatal diagnosis of placenta accreta; however, specificity does not appear to be as good as reported in other studies. In the case of inconclusive findings with one imaging modality, the other modality may be useful for clarifying the diagnosis.

Magnesium sulfate compared with nifedipine for acute tocolysis of preterm labor: a randomized controlled trial.

OBJECTIVE: To compare the efficacy and side effects of intravenous magnesium to oral nifedipine for acute tocolysis of preterm labor. METHODS: A multicenter randomized trial was performed. Patients in active preterm labor who were at 24 to 33 weeks and 6 days of gestation were randomly assigned to receive magnesium sulfate or nifedipine. The primary outcome was arrest of preterm labor, defined as prevention of delivery for 48 hours with uterine quiescence. RESULTS: One hundred ninety-two patients were enrolled. More patients assigned to magnesium sulfate achieved the primary outcome (87% compared with 72%, P=.01). There were no differences in delivery within 48 hours (7.6% magnesium sulfate compared with 8.0% nifedipine, P=.92), gestational age at delivery (35.8 compared with 36.0 weeks, P=.61), birth before 37 and 32 weeks (57% compared with 57%, P=.97, and 11% compared with 8%, P=.39), and episodes of recurrent preterm labor. Mild and severe maternal adverse effects were significantly more frequent with magnesium sulfate. Birth weight, birth weight less than 2,500 g, and neonatal morbidities were similar between groups, but newborns in the magnesium sulfate group spent longer in the neonatal intensive care unit (8.8+/-17.7 compared with 4.2+/-8.2 days, P=.007). CONCLUSION: Patients who received magnesium sulfate achieved the primary outcome more frequently. However, delay of delivery, gestational age at delivery, and neonatal outcomes were similar between groups. Nifedipine was associated with fewer maternal adverse effects.

A randomized trial of amnioreduction versus septostomy in the treatment of twin-twin transfusion syndrome.

OBJECTIVE: Left untreated, severe twin-to-twin transfusion syndrome (TTTS) presenting in the early second trimester of pregnancy is often associated with significant maternal morbidity and almost universal perinatal loss. Removal of excessive amounts of amniotic fluid through serial amniocenteses (amnioreduction) has been the mainstay of therapy. We sought to compare amnioreduction to intentional perforation of the intervening twin membrane (septostomy). STUDY DESIGN: Pregnant women with TTTS before 24 weeks' gestation were randomly assigned to serial amnioreduction or septostomy. A single puncture technique under ultrasound guidance was used for the septostomy. The primary outcome measure was survival to neonatal discharge, and was assessed based on the number of pregnancies or the number of fetuses as appropriate. RESULTS: The study was terminated at the planned interim analysis stage after 73 women were enrolled. This was because the rate of survival of at least 1 infant was similar in the amnioreduction group compared to the septostomy group (78% vs 80% of pregnancies, respectively; RR=0.94, 95%CI 0.55-1.61; P=.82). Patient undergoing septostomy were more likely to require a single procedure for treatment (64% vs 46%; P=.04). CONCLUSION: Although overall perinatal survival is not enhanced, septostomy offers the advantage of often requiring a single procedure compared to serial amnioreduction in the treatment of severe twin-to-twin transfusion syndrome.

Subclavian vein thrombosis following IVF and ovarian hyperstimulation: a case report.

Thromboembolic phenomena are a serious consequence of assisted reproductive technology. We present a case of upper extremity deep vein thrombosis (DVT) at 7 weeks gestation following ovarian hyperstimulation syndrome (OHSS) and IVF. Three weeks after recovering from OHSS, the patient presented with left neck pain and swelling. Ultrasound revealed a thrombus in the left jugular vein and left subclavian vein. Low molecular weight heparin (LMWH) was initiated with symptom resolution within 1 week. The patient remained on LWMH throughout her pregnancy and delivered at term. A literature review showed 97 published cases of thromboembolism following ovulation induction. A majority of these cases was associated with OHSS and pregnancy and the site of involvement was predominantly in the upper extremity and neck. Infertility physicians and obstetricians should be aware of this complication and keep in mind that it may occur weeks after resolution of OHSS symptoms.

Detection of sonographic markers of fetal aneuploidy depends on maternal and fetal characteristics.

OBJECTIVES: The purpose of this study was to determine factors that influence the detection rate of sonographic markers of fetal aneuploidy (SMFA). METHODS: We reviewed the sonographic images of 160 consecutive second-trimester trisomic fetuses for the presence of SMFA, either structural anomalies or sonographic soft markers. RESULTS: One hundred forty-nine (93.1%) records were complete and analyzed; 78 cases (52.3%) were identified with 1 or more SMFA. Sonographic markers of fetal aneuploidy were detected in 42.7%, 75.0%, and 90.9% of trisomies 21, 18, and 13, respectively (P<.005). The detection rate of SMFA had a positive linear correlation with gestational age (adjusted R(2)=0.64; P<.002). Sonographic markers of fetal aneuploidy were detected in 43.7% of fetuses of less than 18.0 weeks' gestation and 64.5% of fetuses of 18.0 weeks' gestation or greater (likelihood ratio=6.4; P<.01). Sonographic markers of fetal aneuploidy were detected in 23.5% of patients with suboptimal image quality versus 58.3% of the others (likelihood ratio=7.5; P<.05). The rate of structural malformation was similar between the male and female fetuses, whereas that of soft markers was 49.4% in male and 30.0% in female fetuses (odds ratio=2.3; range, 1.2-4.5; P<.02). Factor analysis showed that some soft markers and some structural anomalies tended to appear together. CONCLUSIONS: The type of fetal trisomy, gestational age, sex, and quality of images influence the detection rate of SMFA. The highest detection rate for SMFA in the second trimester is at or above 18 weeks' gestational age. Certain markers are detected in clusters. These findings may explain, in part, the variability in reported rates of detection of SMFA among trisomic fetuses. These findings need to be prospectively tested in the general population of pregnancies for applicability to sonographic risk calculations for fetal trisomies.

Randomized comparison of intravenous nitroglycerin and subcutaneous terbutaline for external cephalic version under tocolysis.

OBJECTIVE: The purpose of this study was to compare the efficacy and safety of intravenous nitroglycerin with that of subcutaneous terbutaline as a tocolytic agent for external cephalic version at term. STUDY DESIGN: We performed a prospective randomized trial. Patients between 37 and 42 weeks of gestation were assigned randomly to receive either 200 microg of intravenous nitroglycerin therapy or 0.25 mg of subcutaneous terbutaline therapy for tocolysis during external cephalic version. The rate of successful external cephalic version and side effects were compared between groups. RESULTS: Of 59 randomly assigned patients, 30 patients received intravenous nitroglycerin, and 29 patients received subcutaneous terbutaline. The overall success rate of external cephalic version in the study was 39%. The rate of successful external cephalic version was significantly higher in the terbutaline group (55% vs 23%; P = .01). The incidence of palpitations was significantly higher in patients who received terbutaline therapy (17.2% vs 0%; P = .02), as was the mean maternal heart rate at multiple time periods. CONCLUSION: Compared with intravenous nitroglycerin, subcutaneous terbutaline was associated with a significantly higher rate of successful external cephalic version at term.

Fetal renal growth as assessed through renal parenchymal area derived from prenatal and perinatal ultrasonography.

PURPOSE: Few quantitative parameters allow for comparison of serial studies in children with prenatally detected genitourinary abnormalities. We establish the first ultrasonographically based fetal renal parenchymal growth curve that could serve as a standard for fetal renal growth assessment. MATERIALS AND METHODS: Longitudinal ultrasounds of 246 normal fetal kidneys from 16 to 38 weeks of gestation were scanned with renal parenchymal area calculated and growth curves plotted. Our previously determined nomogram from birth to adolescence was then combined with this fetal nomogram to produce a composite renal growth curve. Data were plotted as mean parenchymal area +/- 2 SD using lines determined by polynomial regression. RESULTS: Renal growth curves were constructed independently for the right and left fetal kidneys as well as the total fetal renal parenchymal area. The polynomial regression equation for the right renal parenchymal area was y = -0.0076x(2) + 0.7141x - 8.5344 (r(2) = 0.91). The polynomial regression equation for the left renal parenchymal area was y = -0.0036x(2) + 0.5161x - 6.2337 (r(2) = 0.96). The polynomial regression equation for the total fetal renal parenchymal area was y = -0.0113x(2) + 1.234x - 14.814 (r(2) = 0.95). CONCLUSIONS: We propose a new quantitative standard to evaluate appropriate fetal kidney size the prenatal renal parenchymal area growth curve. Renal parenchymal growth curves for the normal fetal kidney may serve as a valuable tool to assess fetal renal pathology.

Pregnancy complicated by severe osteogenesis imperfecta: a report of two cases.

IMPLICATIONS: This case report discusses the anesthetic management of two parturients with severe osteogenesis imperfecta who presented for cesarean delivery. Although the anesthetic management for milder forms of the disease has been previously reported, anesthetic options for cases of this severity have not.