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Dive into the research topics where Nan Okun is active.

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Featured researches published by Nan Okun.


Obstetrics & Gynecology | 2005

Antibiotics for bacterial vaginosis or Trichomonas vaginalis in pregnancy: a systematic review.

Nan Okun; Karen Gronau; Mary E. Hannah

OBJECTIVE: To determine whether antibiotic treatment for bacterial vaginosis or Trichomonas vaginalis during pregnancy decreases the risk of preterm birth and associated adverse outcomes. DATA SOURCES: Pre-MEDLINE and MEDLINE (1966–2003), EMBASE (1980–2003), and the Cochrane Library were searched using the keywords “bacterial vaginosis,” “Trichomonas,” “Trichomonas vaginalis,” “Trichomonas vaginitis,” “Trichomonas infections,” “pregnancy,” “pregnant,” “antibiotics,” and “antibiotic prophylaxis.” METHODS OF STUDY SELECTION: The search produced 1,888 titles, of which 1,256 abstracts were reviewed further. Of these, 1,217 were ineligible. Inclusion criteria were the following: randomized controlled trials in which antibiotics were compared with no antibiotic or placebo, for women in the second or third trimester of pregnancy with symptomatic or asymptomatic bacterial vaginosis or Trichomonas vaginalis, intact membranes, and not in labor. Exclusion criteria were as follows: published in a language other than English, dropout rate of more than 20% of women in either group, and lack of usable outcomes. Of the 39 papers reviewed in detail, 14 studies were included in the meta-analysis. TABULATION, INTEGRATION, AND RESULTS: One of the authors reviewed titles obtained from the searches, and 2 reviewers independently reviewed the abstracts, excluded those that were ineligible, identified eligible papers, and abstracted the data. For women with bacterial vaginosis, antibiotics reduced the risk of persistent infection but did not reduce the risk of preterm birth or the incidence of associated adverse outcomes for the general population or for any subgroup analyzed. For women with Trichomonas vaginalis, metronidazole reduced the risk of persistent infection but increased the incidence of preterm birth. CONCLUSION: Contrary to the conclusions of 3 recent systematic reviews, we found no evidence to support the use of antibiotic treatment for bacterial vaginosis or Trichomonas vaginalis in pregnancy to reduce the risk of preterm birth or its associated morbidities in low- or high-risk women.


Placenta | 2008

Screening for Placental Insufficiency in High-risk Pregnancies: Is Earlier Better?

S.L. Costa; Leslie Proctor; Jodie M Dodd; Meghana Toal; Nan Okun; J.-A. Johnson; Rory Windrim; John Kingdom

OBJECTIVE To compare a profile of placental function between the first and second trimesters in pregnancies at high risk of adverse perinatal outcomes attributable to placental insufficiency. STUDY DESIGN Prospective cohort study in 61 singleton pregnancies. Uterine artery Doppler and placental morphology (shape and texture) were determined at 11-13(+6) weeks and at 18-23(+6) weeks. First trimester (pregnancy-associated placental protein-A [PAPP-A]) and second trimester (total hCG and alpha fetoprotein [AFP]) serum biochemistry were determined. The two screening periods were compared for the prediction of a range of severe adverse perinatal outcomes (intrauterine growth restriction [IUGR], abruption, severe pre-eclampsia/HELLP syndrome, delivery<32 weeks, or stillbirth). RESULTS Adverse perinatal outcomes occurred in 14 (23%) women; 3 (4.9%) losses<20 weeks, 2 (3.3%) stillbirths>20 weeks, 4 (6.6%) IUGR, 7 (11.5%) severe pre-eclampsia/HELLP syndrome, and 10 (16.4%) deliveries<32 weeks. Abnormal second trimester placental morphology was significantly associated with adverse outcome [+LR: 3.6, 95% CI: 1.3-8.5; -LR: 0.63, 95% CI: 0.36-0.93; p=0.025], as was > or = 1 abnormal second trimester tests [+LR: 5.9, 95% CI: 1.6-24; -LR: 0.68, 95% CI: 0.59-0.89; p=0.005] or > or = 2 abnormal second trimester tests [+LR: 3.6, 95% CI: 1.3-7.7; -LR: 0.58, 95% CI: 0.27-0.94; p=0.035]. No combination of first trimester tests significantly predicted severe adverse perinatal outcomes. A study sample size of 822 women with similar high-risk characteristics would be needed in order to refute the conclusion that present methods of first trimester screening are not inferior to second trimester screening for severe placental insufficiency (p=0.05, power 80%, z-test). CONCLUSIONS In clinically high-risk pregnancies, prediction of adverse perinatal outcomes using placental function testing is more effective in the second compared with the first trimester.


Ultrasound in Obstetrics & Gynecology | 2011

Retrospective review of diagnostic performance of intracranial translucency in detection of open spina bifida at the 11–13‐week scan

Katherine Fong; Ants Toi; Nan Okun; E. Al-Shami; Ravi Menezes

To evaluate diagnostic performance of intracranial translucency (IT) for detection of open spina bifida and interobserver agreement for visualization of IT during the 11–13‐week scan.


American Journal of Obstetrics and Gynecology | 2003

Effectiveness of cervical cerclage for a sonographically shortened cervix: A systematic review and meta-analysis

Timea Belej-Rak; Nan Okun; Rory Windrim; Susan Ross; Mary E. Hannah

OBJECTIVE The purpose of this study was to determine the effectiveness of cerclage for a shortened cervix on transvaginal ultrasound scanning in terms of the rates of preterm delivery and adverse neonatal and maternal outcomes. STUDY DESIGN Pre-MEDLINE and MEDLINE, EMBASE, and the Cochrane Library were searched for human studies that compared cerclage placement to no cerclage on the basis of transvaginal ultrasound findings of a short cervix (< or =2.5 cm). Two authors independently determined eligibility and abstracted data. Meta-analyses were conducted when possible. RESULTS Thirty-five studies were reviewed; 6 studies were eligible and were included in the analysis. There was no statistically significant effect of cerclage on the rates of preterm delivery (<37, <34, <32, and <28 weeks of gestation), preterm labor, neonatal mortality or morbidity, gestational age at delivery, or time to delivery. Birth weight was significantly higher with than without cerclage (P=.004). CONCLUSION The available evidence does not support cerclage for a sonographically detected short cervix. A randomized controlled trial is needed to determine whether this intervention will reduce adverse neonatal outcomes.


Obstetrical & Gynecological Survey | 2013

Emergency Cerclage: Literature Review

Shirin Namouz; Shay Porat; Nan Okun; Rory Windrim; Dan Farine

Abstract This article reviews the use and effectiveness of emergency cerclage for women who present with a dilated cervix in the second trimester of pregnancy and seeks to identify predictors of favorable emergency cerclage outcomes. We searched PubMed and the Cochrane Library for the period January 1995 to April 2012 and used the terms “emergency cerclage,” “emergency stitch,” “rescue cerclage,” and “rescue stitch.” Thirty-four studies in which transvaginal emergency cervical cerclage was performed in women with a dilated cervix were identified and included. Predictors of poor outcome were prolapsed membranes, evidence of intra-amniotic or systemic infection, symptomatic presentation, cervical dilatation greater than 3 cm, or cerclage after 22 weeks. According to observational and limited randomized controlled trials, the cerclage group did significantly better than the bed-rest group in mean randomization-to-delivery interval, preterm delivery before 34 weeks, and compound neonatal morbidity. The current data suggest that emergency cerclage is associated with a longer latency period and, most often, with better pregnancy outcomes when compared with bed rest. Many of the predictors of adverse outcomes appear to be associated with evidence of inflammation or infection. Target Audience: Obstetricians and gynecologists, family physicians Learning Objectives: After completing this CME activity, physicians should be better able to review the use and evaluate the effectiveness of emergency cerclage for women who present with a dilated cervix in the second trimester, to identify predictors of favorable emergency cerclage outcomes, and to compare emergency cerclage versus bed rest.


Fertility and Sterility | 2016

Pregnancy outcomes in women with polycystic ovary syndrome undergoing in vitro fertilization

Lynn Sterling; Jennifer Liu; Nan Okun; Anamika Sakhuja; Sony Sierra; Ellen M. Greenblatt

OBJECTIVE To determine whether the diagnosis of polycystic ovary syndrome (PCOS) independently predicts increased rates of pregnancy complications relative to control subjects, after adjusting for important confounders. DESIGN Retrospective cohort. SETTING Not applicable. PATIENT(S) A review of all pregnancies after fresh IVF with or without intracytoplasmic sperm injection transfers from December 2006 to 2012 (n = 1,084) identified 394 eligible singleton births (71 women with PCOS; 323 controls without). INTERVENTION(S) Not applicable. MAIN OUTCOME MEASURE(S) Singleton births were assessed for selected adverse pregnancy and birth outcomes. RESULT(S) Women with PCOS demonstrated a higher risk of developing the following pregnancy complications after adjusting for differences in age, parity, body mass index, and time to conception: gestational diabetes (adjusted odds ratio [AOR] 3.15, 95% confidence interval [CI] 1.35-7.33), hypertensive disorders of pregnancy (AOR 4.25, 95% CI 1.94-9.32), preterm birth <37 weeks (AOR 2.30, 95% CI 1.07-4.97), and large for gestational age >90th percentile (AOR 2.77, 95% CI 1.21-6.35). The increased risk of preterm birth <37 weeks was eliminated after adjusting for development of hypertensive disorders of pregnancy, whereas the increased risk of large for gestational age remained significant after adjusting for gestational diabetes mellitus status. Time to conception did not differ significantly between groups, nor did rates of antepartum hemorrhage, cesarean section, or perinatal mortality. CONCLUSION(S) Polycystic ovary syndrome independently predicts higher risk of adverse pregnancy outcomes after adjusting for differences in maternal age, parity, body mass index, and time to conception. This new information may be of relevance in counseling and monitoring women with PCOS, although larger prospective studies may be needed to validate our findings.


Prenatal Diagnosis | 2010

Fetal anatomic survey using three‐dimensional ultrasound in conjunction with first‐trimester nuchal translucency screening

Mousumi Bhaduri; Katherine Fong; Ants Toi; George Tomlinson; Nan Okun

To determine the visualization rates of fetal anatomic structures by three‐dimensional ultrasound (3DUS) at 12–13 weeks of gestation.


Journal of obstetrics and gynaecology Canada | 2004

Treatment options in fetomaternal hemorrhage: four case studies.

Lori Weisberg; John Kingdom; Sarah Keating; Greg Ryan; Gareth Seaward; Edmond Kelly; Nan Okun; Rory Windrim

BACKGROUND Significant fetomaternal hemorrhage (FMH) is an uncommon event that places the fetus at risk of severe morbidity and mortality. Symptoms and signs at presentation are subtle and, if promptly recognized, appropriate management may permit the fetus to escape serious injury. CASES Four cases of significant FMH were diagnosed in the high-risk obstetrical unit at Mount Sinai Hospital, Toronto, during 2003. Three of the women complained of reduced fetal movements and were investigated initially with a non-stress test, a Kleihauer-Betke test, and ultrasound, including Doppler of the middle cerebral artery. These women all required emergency Caesarean section for non-reassuring fetal status. One fetus was treated by intravascular transfusion. Another identified case was transfused postnatally. One asymptomatic case was identified after spontaneous vaginal birth and also treated by neonatal transfusion. Neurological outcomes were good in all four cases. CONCLUSIONS Reduced fetal movements may be the only complaint of FMH. Increased awareness is required to ensure a diagnosis is made. When a non-stress test for reduced fetal movement is non-reactive, a Kleihauer-Betke test should be ordered, as well as detailed ultrasonography, including fetal Doppler studies. The perinatal prognosis for FMH may improve by facilitating the appropriate use of fetal blood transfusion or delivery by Caesarean section.


Prenatal Diagnosis | 2013

The impact of maternal weight discrepancies on prenatal screening results for Down syndrome.

Tianhua Huang; Wendy S. Meschino; Nan Okun; Alan Dennis; Barry Hoffman; Nathalie Lepage; Shamim Rashid; Ritu Aul; Sandra A. Farrell

This study aimed to assess the quantitative impact of maternal weight discrepancy on the screen result for Down syndrome when using Integrated Prenatal Screening and First Trimester Combined Screening.


Endocrine Practice | 2013

Iodine nutrition during pregnancy in Toronto, Canada.

Pamela M. Katz; Angela M. Leung; Lewis E. Braverman; Elizabeth N. Pearce; George Tomlinson; Xuemei He; Jaclyn Vertes; Nan Okun; Paul G. Walfish; Denice S. Feig

OBJECTIVE To evaluate the status of iodine nutrition among pregnant women presenting for routine antenatal care in Toronto, Canada, as determined by the median urine iodine concentration (UIC) of this population. METHODS A cross-sectional, observational study was conducted involving 142 pregnant women recruited from four low-risk antenatal outpatient clinics in Toronto, Canada. Subjects completed a questionnaire and provided a spot urine sample for the measurement of iodine concentration. RESULTS Mean maternal age was 33.8 ± 4.3 years. Mean gestational age was 29.3 ± 7.8 weeks. The median UIC was 221 μg/L (interquartile range, 142 to 397 μg/L). Six women (4.2%) had urine iodine levels <50 μg/L, and 36 women (25.4%) had levels between 50 and 150 μg/L. CONCLUSION This cohort of primarily Caucasian, well-educated, and relatively affluent pregnant women in Toronto, Canada, are iodine sufficient, perhaps due to universal salt iodization and/or other dietary and lifestyle factors.

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Mary E. Hannah

Sunnybrook Health Sciences Centre

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Ants Toi

University of Toronto

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R. Douglas Wilson

University of British Columbia

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