P C Tan

University of Malaya, Kuala Lumpur, Kuala Lumpur, Malaysia

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Publications (16)26.23 Total impact

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    Article: Oral nifedipine versus intravenous labetalol for acute blood pressure control in hypertensive emergencies of pregnancy: a randomised trial.
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    ABSTRACT: To compare oral nifedipine with intravenous labetalol in their rapidity to control hypertensive emergencies of pregnancy. A double-blind randomised trial. A university hospital in Malaysia. Pregnant women with severe gestational hypertension≥160/110 mmHg who required immediate treatment. Patients were randomised to receive nifedipine (10 mg tablet, orally, up to five doses) and intravenous placebo saline injection or intravenous labetalol injection (in an escalating dose regimen of 20, 40, 80, 80 and 80 mg) and a placebo tablet every 15 minutes until the target blood pressure of ≤150/100 mmHg was achieved. Crossover treatment was effected if the initial treatment regimen was unsuccessful. MAIN OUTCOME MEASURE  The time taken to achieve a blood pressure of ≤150/100 mmHg. The median time taken to achieve target blood pressure was 30 minutes (interquartile range, IQR 22.5-67.5 minutes) versus 45 minutes (IQR 30-60 minutes) for nifedipine and labetalol, respectively (P=0.59). Repeated measures analysis of variance indicated that in the first hour both systolic (F=87.6, P<0.001) and diastolic (F=55.8, P<0.001) blood pressure significantly decreased, but there was no difference between the nifedipine and labetalol groups for both systolic (F=0.12, P=0.74) and diastolic (F=0.92, P=0.34) blood pressure trends over time. Crossover treatment was required in 20% of women from each group. Oral nifedipine and intravenous labetalol regimens are similarly effective in the acute control of severe hypertension in pregnancy.
    BJOG An International Journal of Obstetrics & Gynaecology 01/2012; 119(1):78-85. · 3.41 Impact Factor
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    Article: Predominance of Blastocystis sp. subtype 4 in rural communities, Nepal.
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    ABSTRACT: Blastocystis sp. is a common intestinal parasite. To date, there have been sporadic and scanty studies on Blastocystis sp. carried out in rural communities in Nepal. We surveyed the prevalence of Blastocystis sp. and its possible associated risk factors, and reported the predominant Blastocystis sp. subtype in two rural communities, Bolde Phediche and Bahunipati, in Nepal. Human faecal samples were collected from 241 participants, cultured using in vitro cultivation and examined for Blastocystis sp. The presence of Blastocystis sp. in faecal samples was further confirmed by polymerase chain reaction (PCR) and subsequently genotyped using subtype-specific sequence tagged site (STS) primers. There were 26.1% (63/241) of the participants that were infected by Blastocystis sp. We detected 84.1% (53/63) of Blastocystis sp. subtype 4 infections in these rural communities. The unusually high prevalence of Blastocystis sp. subtype 4 can be attributed to the rearing of family-owned animals in barns built close to their houses. Eighty one percent (51/63) of the Blastocystis sp. infected participants drank not boiled or unfiltered water. The present study revealed that Blastocystis sp. could pose a health concern to the communities and travellers to the hilly area in Nepal. Infection may be transmitted through human-to-human, zoonotic and waterborne transmissions. We provide recommendations to ensure good public health practices.
    Parasitology Research 11/2011; 110(4):1553-62. · 2.15 Impact Factor
  • Article: Maternal hemoglobin level and red cell indices as predictors of gestational diabetes in a multi-ethnic Asian population.
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    ABSTRACT: To evaluate maternal hemoglobin levels and red cell indices as predictive factors for gestational diabetes (GDM). Data from 1,538 women were analyzed. At the first visit for prenatal care, the 50-gram glucose challenge test was followed by the 75-gram glucose tolerance test in those who screened positive. GDM was diagnosed based on the WHO (1999) criteria. Maternal complete blood count was obtained at the first visit, hospitalization for birth, and after birth. Receiver operator characteristic curves were generated to establish thresholds. Multivariable logistic regression analyses were performed to establish independent predictors of GDM. GDM was diagnosed in 182/1,538 (11.8%). GDM was associated with hemoglobin level, hematocrit and erythrocyte count at the first visit for prenatal care only. Hemoglobin threshold at the first visit was established at 11.5 g/dl. After adjustment, high hemoglobin [AOR 1.5 (95% CI 1.0-2.1); p = 0.027] remained predictive of GDM. High maternal hemoglobin level at the first prenatal visit is independently predictive of GDM.
    Clinical and experimental obstetrics & gynecology 01/2011; 38(2):150-4. · 0.43 Impact Factor
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    Article: Coitus and orgasm at term: effect on spontaneous labour and pregnancy outcome.
    P C Tan, C M Yow, S Z Omar
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    ABSTRACT: Coitus and orgasm in late pregnancy are believed to facilitate the onset of labour. We aim to evaluate the relationship at term of reported coitus and orgasm with spontaneous labour. Women at term scheduled for non-urgent labour induction were asked to keep a coitus and orgasm diary. These women were recruited for a randomised trial on the effect of coitus to promote spontaneous labour. For this analysis, the women were categorised into coitally-active and abstinent groups according to their coital diary. Spontaneous labour prior to the date of scheduled labour induction was the primary outcome. Labour, delivery and neonatal outcome were also evaluated. Multivariable logistic regression analysis was used to control for significant variables. On univariate analysis, the inverse association of coitus with spontaneous labour was borderline (odds ratio [OR] 0.6; 95 percent confidence interval [CI] 0.3-1.0; p-value is 0.052). Orgasm was not associated with spontaneous labour (p-value is 0.33). After adjustment, coitus (adjusted OR 0.4; 95 percent CI 0.2-0.8; p-value is 0.009) displayed a significant inverse association with spontaneous labour. Coitus and orgasm were not associated with any other adverse pregnancy outcome. Women who reported coitus were less likely to go into spontaneous labour prior to their scheduled labour induction. Reported coitus and orgasm were not associated with adverse pregnancy outcome.
    Singapore medical journal 11/2009; 50(11):1062-7. · 0.73 Impact Factor
  • Article: Transvaginal sonography of cervical length and Bishop score as predictors of successful induction of term labor: the effect of parity.
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    ABSTRACT: To evaluate the predictive value for successful labor induction of transvaginal ultrasound (TVS) of cervical length according to parity. TVS of the cervix was performed before term labor induction. Induction was considered successful if vaginal delivery was achieved within 24 hours; 231 women were available for final analysis. Analysis of the receiver operator characteristics curve showed an optimal cut-off for cervical length of < or = 20 mm for successful induction. Following multivariate logistic regression analysis, a sonographic short cervix (AOR 5.6; p < 0.001) was an independent predictor of successful induction but not a favorable Bishop score (p = 0.47). Among multiparas with a short cervix, positive and negative predictive values for successful induction were 98% (95% CI 90-100%) and 21% (95% CI 13%-32%) and among nulliparas, predictive values were 69% (95% CI 53%-82%) and 77% (95% CI 64%-87%) respectively. In nulliparas, cervical length can usefully predict labor induction outcome.
    Clinical and experimental obstetrics & gynecology 01/2009; 36(1):35-9. · 0.43 Impact Factor
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    Article: Predictors of newborn admission after labour induction at term: Bishop score, pre-induction ultrasonography and clinical risk factors.
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    ABSTRACT: Following labour induction at term, 12 percent of neonates can expected to be admitted to the neonatal intensive care unit. We aimed to evaluate the Bishop score, pre-induction ultrasonography (US) assessment of amniotic fluid, foetal weight and cervical length, and pre-induction and intrapartum risk factors as predictors of neonatal admission. 152 women at term, scheduled for labour induction, consented to participate in this prospective study. Transabdominal US was performed to obtain foetal biometry and amniotic fluid index, followed by transvaginal US to measure cervical length. US findings were concealed. The Bishop score was obtained at initiation of labour induction. Pre-induction and intrapartum risk factors were also considered in the multivariate logistic regression analysis. All study women received standard care. On univariate analysis, factors associated with neonatal admission were: gestational age at less than or equal to 40 weeks, labour induction for diabetes mellitus, Bishop score of less than 5 at initiation of labour induction, estimated foetal weight of less than 2.5 kg by US, induction to delivery interval of more than 24 hours, caesarean delivery and umbilical cord blood pH of less than 7.1. Cervical length of greater than 20 mm on transvaginal US (p-value is 0.10) was not significant. After multivariate logistic regression analysis, controlling for the significant variables, only the unfavourable Bishop score (adjusted OR 4.2; 95% CI 1.2-13.8; p-value is 0.02) and caesarean delivery (adjusted OR 3.9; 95% CI 1.1-13.7; p-value is 0.035) were independent predictors of neonatal admission. The identification of an unfavourable Bishop score as an independent predictor of neonatal admission is useful in the counselling of women who are considering labour induction.
    Singapore medical journal 04/2008; 49(3):193-8. · 0.73 Impact Factor
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    Article: Predictors for caesarean delivery and neonatal admission after trial of labour in women with one previous lower segment caesarean scar.
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    ABSTRACT: Caesarean delivery rates are still increasing, and reliable predictors of adverse outcomes at a subsequent trial of scar are important as they guide decision-making on the best mode of delivery. We aimed to evaluate whether there are any predictors for caesarean delivery and neonatal admission, following trial of labour after one lower transverse caesarean section. 768 women at term with singleton gestation and who had undergone a trial of labour between June 2002 and December 2005, were retrospectively identified using the labour ward register. 51 infants were admitted to a neonatal unit. Case notes for these cases were retrieved. Emergency repeat caesarean delivery and neonatal admission were the main outcome measures. Following multivariate logistic regression analysis, no previous vaginal birth (adjusted odds-ratio [AOR] 3.4), diabetes mellitus or hypertension in pregnancy (AOR 1.7), induction of labour (AOR 2.0), oxytocin use in labour (AOR 2.4), and meconium-stained liquor (AOR 4.9) were independent predictors of emergency caesarean delivery. Diabetes mellitus or hypertension in pregnancy (AOR 3.1), prelabour rupture of membranes (AOR 4.7) and caesarean delivery (AOR 6.0) were independent predictors of neonatal admission. Predictors for emergency caesarean delivery and neonatal admission following a trial of labour can be identified. This information should be incorporated into the counselling of women contemplating a trial of labour. The strongest predictor for neonatal admission was emergency caesarean delivery, further emphasising the need for careful case selection in a trial of labour to minimise the risk of failure.
    Singapore medical journal 04/2008; 49(3):188-92. · 0.73 Impact Factor
  • Article: Alpha-thalassaemia in association with beta-thalassaemia patients in Malaysia: a study on the co-inheritance of both disorders.
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    ABSTRACT: Individuals with double heterozygosity for alpha- and beta-thalassaemia and heterozygous beta-thalassaemia show a similar haematological picture. Co-inheritance of alpha- and beta-thalassaemia in both partners may result in pregnancies with either Hb Bart's hydrops foetalis or beta-thalassaemia major, or pregnancies with both disorders. The co-inheritance of alpha-thalassaemia in 322 beta-thalassaemia carriers in Malaysia was studied. The frequency of alpha-thalassaemia in the beta-thalassaemia carriers was 12.7% (41/322), with a carrier frequency of 7.8% for the SEA deletion, 3.7% for the -alpha(3.7) deletion, 0.9% for Hb Constant Spring and 0.3% for the -alpha(4.2) deletion. Double heterozygosity for alpha- and beta-thalassaemia was confirmed in 5 out of the 41 couples and the risk of the fatal condition Hb Bart's hydrops foetalis was confirmed in two of these couples. Detection of the Southeast Asian (SEA) deletion in the Malaysian Malays in this study confirms that Hb Bart's hydrops foetalis can occur in this ethnic group. Results of this study have provided new information on the frequency and different types of alpha-thalassaemia (--(SEA), -alpha(3.7) and -alpha(4.2) deletions, Hb Constant Spring) in Malaysian beta-thalassaemia carriers.
    Community Genetics 02/2008; 11(3):129-34. · 1.32 Impact Factor
  • Article: Concurrent oxytocin with dinoprostone pessary versus dinoprostone pessary in labour induction of nulliparas with an unfavourable cervix: a randomised placebo-controlled trial.
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    ABSTRACT: To compare concurrent oxytocin with dinoprostone pessary versus dinoprostone pessary in labour induction for nulliparas with an unfavourable cervix. A randomised double-blind study. University Malaya Medical Centre, Malaysia. Nulliparas at term with intact membranes, Bishop score < or = 6 and admitted for labour induction. All women received 3 mg dinoprostone pessary for labour induction. Those randomised to the oxytocin arm received oxytocin infusion started at 1 micro/minute and doubled every 30 minutes to a maximum 16 micro/minute. Women assigned to placebo received identical volume of saline infusion. After 6 hours, infusion was stopped and vaginal reassessment performed to guide further management. Primary outcome was vaginal delivery within 24 hours. Concurrent oxytocin infusion with dinoprostone pessary did not significantly increase vaginal delivery rate within 24 hours (48.6 versus 35.9%; P = 0.07, relative risk [RR] 1.4 [95% CI 1.0-1.9]). It reduced the requirement for repeat dinoprostone (37.1 versus 61.2%; P = 0.001, RR 0.61 [95% CI 0.45-0.81]) and improved maternal satisfaction with the birth process (median score of 3 versus 5 on a 10-point visual analogue scale, P = 0.007). Caesarean rates were not different (41.9 versus 44.7%, P = 0.52). Labour induction with concurrent oxytocin infusion and vaginal dinoprostone could be considered for nulliparas with an unfavourable cervix. Larger studies are needed.
    BJOG An International Journal of Obstetrics & Gynaecology 07/2007; 114(7):824-32. · 3.41 Impact Factor
  • Article: Transvaginal sonographic measurement of cervical length vs. Bishop score in labor induction at term: tolerability and prediction of Cesarean delivery.
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    ABSTRACT: To compare transvaginal sonography for cervical length measurement and digital examination for Bishop score assessment in women undergoing labor induction at term, to assess their tolerability (in terms of pain) and ability to predict need for Cesarean delivery. A prospective study was performed on 249 women admitted for labor induction. Cervical length was measured using transvaginal ultrasound examination. A 10-point visual analog scale (VAS) for procedure-related pain was obtained. Bishop score was determined just before labor induction and another pain score was obtained. Delivery outcome was recorded. Analyses were by t-test, Fisher's exact test, receiver-operating characteristics (ROC) curves and multivariate logistic regression. Transvaginal sonography was significantly less painful than digital examination for Bishop score assessment (mean difference in VAS score 3.46; P<0.001). Analyses of the ROC curves for cervical length and Bishop score indicated that both were predictors of Cesarean delivery (area under the curve 0.611 vs. 0.607; P=0.012 vs. P=0.015, respectively) with optimal cut-offs for predicting Cesarean delivery of >20 mm for cervical length and Bishop score<or=5. Cervical length had superior sensitivity (80% vs. 64%) and marginally better positive (30% vs. 27%) and negative (89% vs. 83%) predictive values. Multivariate logistic regression analysis revealed that only nulliparity (adjusted odds ratio (AOR) 4.1; 95% CI, 2.1-8.1; P<0.001) and transvaginal sonographic cervical length>20 mm (AOR 3.4; 95% CI, 1.4-8.1; P=0.006) were independent predictors of Cesarean delivery. Transvaginal sonography for cervical length measurement is better tolerated than digital examination for Bishop score assessment. Both cervical length and Bishop score are useful predictors of the need for Cesarean delivery following labor induction. A cervical length>20 mm at labor induction at term is an independent predictor of Cesarean delivery.
    Ultrasound in Obstetrics and Gynecology 05/2007; 29(5):568-73. · 3.01 Impact Factor
  • Article: The fetal sex ratio and metabolic, biochemical, haematological and clinical indicators of severity of hyperemesis gravidarum.
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    ABSTRACT: The association between female fetal sex and hyperemesis gravidarum is well established in European and North American populations. The association between female fetuses and severity of hyperemesis remains uncertain. A retrospective study based on case notes review of 166 Asian women hospitalised for hyperemesis was performed. Female fetuses were significantly associated with hyperemesis in our population (P= 0.004, OR 1.6, 95% CI 1.2-2.2) as well as associated with severe ketonuria and high urea. When both severe ketonuria and high urea were present at initial hospital admission for hyperemesis, 83% (95% CI 66-93) of the fetuses were female.
    BJOG An International Journal of Obstetrics & Gynaecology 07/2006; 113(6):733-7. · 3.41 Impact Factor
  • Article: Indicators of prolonged hospital stay in hyperemesis gravidarum.
    International Journal of Gynecology & Obstetrics 07/2006; 93(3):246-7. · 2.05 Impact Factor
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    Article: Rapid and cost-effective antenatal diagnosis of haemoglobin Bart's hydrops foetalis syndrome using a duplex-polymerase chain reaction.
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    ABSTRACT: Haemoglobin Bart's hydrops foetalis syndrome (--SEA/--SEA) is not compatible with life and contributes to a majority of the hydropic foetuses in the Malaysian Chinese alpha-thalassaemia carriers who possess the 2-alpha-gene deletion in cis (--SEA/alphaalpha). A duplex-PCR which simultaneously amplifies a normal 136 bp sequence between the psialpha-alpha2-globin genes and a 730 bp Southeast Asian deletion-specific sequence (--SEA) between the psialpha2-theta1-globin genes was established. The duplex-PCR which detects the --SEA deletion in both chromosomes serves as a rapid and cost-effective confirmatory test in the antenatal diagnosis of Haemoglobin Bart's hydrops foetalis syndrome in Malaysia. In addition, the duplex-PCR is simple to perform as both the normal and deletion-specific alpha-globin gene sequences are amplified in the same PCR reaction.
    The Medical journal of Malaysia 11/2005; 60(4):447-53.
  • Article: Molecular defects in the beta-globin gene identified in different ethnic groups/populations during prenatal diagnosis for beta-thalassemia: a Malaysian experience.
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    ABSTRACT: Beta-thalassemia is the most-common genetic disorder of hemoglobin synthesis in Malaysia, and about 4.5% of the population are heterozygous carriers of the disorder. Prenatal diagnosis was performed for 96 couples using the Amplification Refractory Mutation System and Gap-Polymerase Chain Reaction. We identified 17 beta-globin defects-initiation codon for translation (T-G), -29 (A-G), -28 (A-G), CAP +1 (A-C), CD 8/9 (+G), CD 15 (G-A), CD 17 (A-T), CD 19 (A-G), Hb E (G-A), IVS1-1 (G-T), IVS1-5 (G-C), CD 41/42 (-CTTT), CD 71-72 (+A), IVS2-654 (CT), poly A(A-G), 100-kb Ggamma(Agammadeltabeta) degrees and 45-kb Filipino deletions. The 192 beta-alleles studied comprised Chinese (151 patients), Malay (21), Orang Asli from East Malaysia (15), Filipino (1), Indian (1), Indonesian Chinese (2), and Thai (1). In the Chinese, 2 beta-globin defects at CD 41/42 and IVS2-654 were responsible for 74% of beta-thalassemia. beta-mutations at CD 19, IVS1-1 (G-T), IVS1-5, poly A, and hemoglobin E caused 76% of the hemoglobin disorders in the Malays. The Filipino 45-kb deletion caused 73.3% of bthalassemia in the Orang Asli. Using genomic sequencing, the rare Chinese beta-mutation at CD 43 (G-T) was confirmed in 2 Chinese, and the Mediterranean mutation IVS1-1 (G-A) was observed in a Malay beta-thalassemia carrier. The beta-globin mutations confirmed in this prenatal diagnosis study were heterogenous and 65 (68%) couples showed a different globin defect from each other. The use of specific molecular protocols has allowed rapid and successful prenatal diagnosis of beta-thalassemia in Malaysia.
    Clinical and Experimental Medicine 01/2005; 4(3):142-7. · 1.58 Impact Factor
  • Article: Molecular defects in the β-globin gene identified in different ethnic groups/populations during prenatal diagnosis for β-thalassemia: a Malaysian experience
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    ABSTRACT: β-thalassemia is the most-common genetic disorder of hemoglobin synthesis in Malaysia, and about 4.5% of the population are heterozygous carriers of the disorder. Prenatal diagnosis was performed for 96 couples using the Amplification Refractory Mutation System and Gap-Polymerase Chain Reaction. We identified 17 β-globin defects-initiation codon for translation (T-G), -29 (A-G), -28 (A-G), CAP +1 (A-C), CD 8/9 (+G), CD 15 (G-A), CD 17 (A-T), CD 19 (A-G), Hb E (G-A), IVS1-1 (G-T), IVS1-5 (G-C), CD 41/42 (-CTTT), CD 71–72 (+A), IVS2-654 (CT), poly A(A-G), 100-kb Gγ(Aγδβ)° and 45-kb Filipino deletions. The 192 β-alleles studied comprised Chinese (151 patients), Malay (21), Orang Asli from East Malaysia (15), Filipino (1), Indian (1), Indonesian Chinese (2), and Thai (1). In the Chinese, 2 β-globin defects at CD 41/42 and IVS2-654 were responsible for 74% of β-thalassemia. β-mutations at CD 19, IVS1-1 (G-T), IVS1-5, poly A, and hemoglobin E caused 76% of the hemoglobin disorders in the Malays. The Filipino 45-kb deletion caused 73.3% of bthalassemia in the Orang Asli. Using genomic sequencing, the rare Chinese β-mutation at CD 43 (G-T) was confirmed in 2 Chinese, and the Mediterranean mutation IVS1-1 (G-A) was observed in a Malay β-thalassemia carrier. The β-globin mutations confirmed in this prenatal diagnosis study were heterogenous and 65 (68%) couples showed a different globin defect from each other. The use of specific molecular protocols has allowed rapid and successful prenatal diagnosis of β-thalassemia in Malaysia.
    Clinical and Experimental Medicine 11/2004; 4(3):142-147. · 1.58 Impact Factor
  • Article: Do fertility intentions predict subsequent behavior? Evidence from Peninsular Malaysia.
    P C Tan, N P Tey
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    ABSTRACT: Data from the 1984 Malaysian Population and Family Survey were matched with birth registration records for 1985-87 to determine the accuracy of statements regarding desired family size that were reported in a household survey in predicting subsequent reproductive behavior. The findings of this study were that stated fertility intention provides fairly accurate forecasts of fertility behavior in the subsequent period. In other words, whether a woman has another child is predicted closely by whether she wanted an additional child. Informational, educational, and motivational activities of family planning programs would, therefore, have greater success in reducing family size if fertility intentions were taken into account.
    Studies in Family Planning 25(4):222-31. · 1.28 Impact Factor