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T Y Leung

Publications and source records attributed to T Y Leung.

At least 19 recordsLinked to original sources
PubMed2007

First-trimester combined screening for trisomy 21 in a predominantly Chinese population.

OBJECTIVE: To examine the effectiveness of first-trimester fetal trisomy 21 screening using a combination of maternal age, nuchal translucency thickness (NT) and maternal serum free beta-human chorionic gonadotropin (beta-hCG) and pregnancy-associated plasma protein-A (PAPP-A) levels in a predominantly Chinese population in Hong Kong. METHODS: This was a prospective study over a 1.5-year period of 2990 women who underwent combined screening for trisomy 21 between 11+0 and 13+6 weeks of gestation in a university fetal medicine unit. NT was measured according to the criteria set by The Fetal Medicine Foundation (FMF), maternal serum free beta-hCG and PAPP-A levels were measured, and the risk of trisomy 21 was calculated using The FMF's algorithm. Fetal karyotyping was advised when the risk was 1 : 300 or above. All subjects were followed up for pregnancy and fetal outcome. RESULTS: Of the 2990 women who underwent the screening program, 99% were Chinese. There were 57 twin pregnancies, giving a total of 3047 fetuses. Thirty-one percent of the women were 35 years old or above. One hundred and eighty-five (6.1%) fetuses were screen-positive; this included 14 cases of trisomy 21 and 17 cases of other chromosomal abnormalities. The positive predictive value was 16.7%. Among the 2862 screen-negative fetuses, only 18 (0.6%) cases had an unknown fetal outcome. There were no cases in which trisomy 21 was missed and the infant was liveborn. CONCLUSION: First-trimester combined screening for fetal trisomy 21 is highly effective among Chinese subjects.

Adult↗
PubMed2006

First-trimester maternal serum levels of placental hormones are independent predictors of second-trimester fetal growth parameters.

OBJECTIVE: To determine whether first-trimester maternal serum levels of pregnancy-associated plasma protein-A (PAPP-A) and free beta-human chorionic gonadotropin (fbeta-hCG) are independent predictors of second-trimester fetal growth parameters. METHODS: This was a cohort study over a 1-year period involving 594 Chinese women who underwent both first-trimester combined screening for Down syndrome and a routine second-trimester ultrasound examination. Maternal PAPP-A and fbeta-hCG levels (expressed in log(10) of multiples of median (MoM)), crown-rump length (CRL) (expressed in standardized Z-score (Z-CRL)), and maternal height and weight, were correlated with the Z-score of biparietal diameter (Z-BPD), femur length (Z-FL) and abdominal circumference (Z-AC) measured in the second trimester, using the Pearson test, followed by multiple regression analysis. RESULTS: Z-BPD, Z-FL and Z-AC were positively correlated with log(10) PAPP-A MoM, CRL and maternal height (all P < 0.05), while log(10) fbeta-hCG MoM was negatively correlated with Z-AC (P < 0.05). After controlling for the effects of CRL, maternal height and weight, log(10) PAPP-A MoM was found to be an independent positive predictor of Z-FL (r = 0.797, P < 0.001) and Z-AC (r = 0.305, P = 0.049), and log(10) fbeta-hCG MoM was an independent negative predictor of Z-FL (r = -0.381, P = 0.023) and Z-AC (r = -0.418, P = 0.002). Neither hormonal level was related to Z-BPD. CONCLUSIONS: First-trimester PAPP-A and fbeta-hCG are independent factors that influence subsequent fetal growth. PAPP-A level is positively correlated with FL and AC in the second trimester, while fbeta-hCG level is negatively correlated with them. However, BPD is not affected by either of the hormones.

Adult↗
PubMed2006

First-trimester maternal serum level of pregnancy-associated plasma protein-A is an independent predictor of fetal maxillary bone length.

OBJECTIVE: To derive a nomogram of fetal maxillary bone length (MAX) for a Chinese population and to study whether first-trimester maternal serum levels of pregnancy-associated plasma protein-A (PAPP-A) is an independent predictor of fetal MAX. METHODS: This was a prospective observational study over 10 months examining Chinese women with a singleton pregnancy who attended the first-trimester screening program for Down syndrome. The subjects had the fetal crown-rump length (CRL), nuchal translucency, MAX, maternal serum PAPP-A and free beta-human chorionic gonadotropin (fbeta-hCG) levels measured. A nomogram of MAX was derived using normal pregnancies with reliable dates. The correlations between MAX, CRL, PAPP-A and fbeta-hCG levels were studied, after correction for gestational dependency using Z-score transformation for the ultrasound markers (Z-MAX and Z-CRL), and logarithmic transformation of multiple of gestation-specific medians for the biochemical markers (log10PAPP-A multiples of the median (MoM) and log10fbeta-hCG MoM), using the Pearson test and multiple regression analysis. RESULTS: During the study period, 607 Chinese women met the inclusion criteria. The mean gestational age at the first-trimester screening was 12 + 4 weeks (SD, 4 days). Curve estimation analysis showed that a linear relationship fit best between MAX and CRL (MAX (mm) = -0.01 + 0.101 * CRL (mm); r = 0.826; P < 0.0001), and between MAX and gestational age (MAX (mm) = -8.465 + 0.170 * gestational age (day); r = 0.754; SD = 0.71; P < 0.0001). There were significant positive correlations between Z-MAX and Z-CRL (r = 0.627; P = < 0.0001), Z-MAX and log10PAPP-A MoM (r = 0.239; P = < 0.0001). Multiple regression analysis showed that both Z-CRL (P = < 0.0001) and log10 PAPP-A MoM (P = 0.048) were independent predictors for Z-MAX. CONCLUSION: Both CRL and maternal levels of PAPP-A are independent predictors of the fetal MAX measured during the first trimester. The positive correlation between PAPP-A levels and fetal MAX is consistent with the known biological function of PAPP-A on bone growth. This association must be adjusted for when both PAPP-A and MAX are combined for screening of Down syndrome.

Asian People↗
PubMed2006

Prediction of intrapartum Cesarean delivery for non-reassuring fetal status after a successful external cephalic version by a low pre-version pulsatility index of the fetal middle cerebral artery.

OBJECTIVE: To determine whether a pre-version Doppler assessment of fetal cerebral and umbilical blood flow can predict the ultimate need for intrapartum Cesarean delivery after a successful external cephalic version (ECV). METHODS: A prospective observational study on women undergoing ECV between 36 and 38 gestational weeks was performed over a 5-year period. The pulsatility index (PI) of the fetal middle cerebral artery (MCA) and umbilical artery, heart rate and amniotic fluid index were measured before ECV. Women who had successful ECV were then divided into three groups according to the mode of delivery: (1) vaginal delivery, (2) intrapartum Cesarean delivery for poor progress and (3) intrapartum Cesarean delivery for non-reassuring fetal status. The fetal blood flow parameters were compared between the groups. Potential predictors were further analyzed using receiver-operating characteristics curves. RESULTS: Of 174 women with successful ECV, 140 (80.5%) had vaginal delivery, 19 (10.9%) required emergency intrapartum Cesarean delivery for non-reassuring fetal status and 15 (8.6%) for poor progress. MCA-PI was significantly lower in the group with non-reassuring fetal status. MCA-PI is predictive of intrapartum Cesarean delivery (area under the curve = 0.68, P = 0.021). The sensitivity and specificity at a cut-off level of 1.4 were 62.5% and 76%, respectively, while at a cut-off level of 1.5 they were 68.8% and 63.5%, respectively. CONCLUSION: Intrapartum Cesarean delivery for non-reassuring fetal status after successful ECV is associated with a lower pre-version fetal MCA-PI.

Breech Presentation↗
PubMed2005

Fetal intra-abdominal umbilical vein varix: what is the clinical significance?

OBJECTIVE: To assess the clinical significance of fetal intra-abdominal umbilical vein (FIUV) varix. METHODS: We reviewed all cases of FIUV varix diagnosed in a university hospital from 1994 to 2003 and searched the English literature for cases of prenatal diagnosis of FIUV varix. The FIUV was considered dilated when the measurements were above 2 SD of the mean for gestational age. Cases reported in the literature were included if they met the diagnostic criteria for FIUV varix. RESULTS: Between 1994 and 2003, 13 fetuses were diagnosed in our hospital as having FIUV varix. Review of the literature revealed an additional 80 cases. Fetal outcome was available for analysis in 91 cases. Additional sonographic abnormalities were detected prenatally in 29 cases (31.9%), most commonly anomalies of the cardiovascular system (including structural and functional abnormalities), hydropic features and anemia. There were nine (9.9%) cases of chromosomal abnormalities. All except one had associated sonographic abnormalities. There were 12 (13%) perinatal losses. Only 54 cases (59.3%) of fetuses with FIUV varix had a normal obstetric outcome. In the 62 cases with isolated FIUV varix, there were five unexplained intrauterine deaths (8.1%) occurring between 29 and 38 weeks of gestation. The incidence of complications, which included intrauterine death, thrombosis of the umbilical vein and abnormal antenatal cardiotocogram, were significantly higher (P = 0.01, Fisher's exact test) if the diagnosis of FIUV varix was made before 26 weeks. CONCLUSIONS: FIUV varix is associated with a high incidence of fetal anomalies and obstetric complications. Detailed sonography is necessary to exclude fetal anomalies. Karyotyping should be offered when additional fetal abnormalities are detected. Intensive surveillance including color Doppler ultrasound should be started from the moment of diagnosis until delivery, especially in those cases presenting early in pregnancy.

Abdomen↗
PubMed2005

Cervical length at 18-22 weeks of gestation for prediction of spontaneous preterm delivery in Hong Kong Chinese women.

OBJECTIVE: To assess the value of a single cervical length measurement by transvaginal sonography (TVS) at the time of mid-trimester anomaly scan for predicting spontaneous preterm delivery (SPD) among Chinese women. METHODS: A prospective observational study was carried out involving 2880 subjects with singleton pregnancies and confirmed gestational age. Cervical length was measured at 18-22 weeks of gestation. RESULTS: The incidence of SPD < 34 weeks and < 37 weeks were 0.7% and 3.7%, respectively. Women with SPD < 34 weeks and SPD < 37 weeks had shorter median cervical lengths (32.6 mm and 36.2 mm, respectively) than those with term deliveries (37.6 mm) (P = 0.006 and 0.025, respectively). The predictive performance of cervical length was better for SPD < 34 weeks compared with < 37 weeks. A cervical length < or = 27 mm, which corresponded to the 4th centile, occurred in 36.8%, 62.5% and 100% of those with SPD < 34, < 30 and < 26 weeks, respectively. The positive likelihood ratio (LR) of a cervical length < or = 27 mm in predicting SPD < 34 weeks was 9.8. Using logistic regression, both short cervix and funneling were independent predictors for SPD < 34 weeks of gestation. The coexistence of funneling and a cervical length < or = 27 mm gave a positive predictive value (PPV) and LR of SPD < 34 weeks of 14.7% and 26.0, respectively. CONCLUSIONS: Mid-trimester cervical length is predictive of SPD in Chinese women. However, given the low PPV of a short cervical length, its clinical utility is still limited in low-risk populations.

Adult↗
PubMed2001

Screening for postnatal depression: are specific instruments mandatory?

BACKGROUND: Few studies have examined the utility of rating scales developed in non-puerperal context in detecting postnatal depression. This study evaluated the utility of the General Health Questionnaire (GHQ) and the Beck Depression Inventory (BDI) in screening for depression among recently delivered women in Hong Kong. METHODS: A prospective cohort of 145 Chinese women completed the GHQ, BDI and Edinburgh Postnatal Depression Scale (EPDS) 6 weeks after delivery. They were then assessed using the non-patient version of the Structured Clinical Interview for DSM-III-R (SCID-NP) to establish psychiatric diagnosis, against which the criterion validity of the GHQ and BDI was evaluated against this clinical diagnosis. The psychometric performance of the GHQ, BDI and EPDS in detecting postnatal depression was assessed using the receiver operating characteristic (ROC) curves. RESULTS: Both Chinese GHQ and BDI had satisfactory sensitivity and positive predictive value in detecting postnatal depression. Their receiver operating characteristic (ROC) curves were comparable to that of the EPDS. LIMITATION: The study was conducted in Chinese women using translated version of the rating scales. CONCLUSIONS: The GHQ and BDI are useful for detecting postnatal depression among recently delivered Chinese women. The results of this study suggest that rating scales developed in non-puerperal context may also be applicable for postnatal depression.

Adolescent↗
PubMed2001

Factors associated with the use of breast and cervical cancer screening services among Chinese women in Hong Kong.

We conducted a cross-sectional survey using a self-administered questionnaire among attendees of a well women clinic in Hong Kong during June and July 1998. The study aimed to examine the factors associated with the past and future use of screening services among Chinese women in Hong Kong and their perception of service providers. Of the 430 respondents (64% response rate), 87% were aged 31-50 y, 85% married, 93% attained education to upper secondary school level, and 96% were non-smokers. Nearly all respondents (99%) reported having sexual experience and most of them (87%) had such experience with only one partner; 59% reported having a pap-smear test, 28% a mammogram and 44% a breast self-examination. Women who were health conscious (ate a lower fat diet and performed regular exercise) were more likely to have used the screening service (mammogram and pap-smear test) and performed breast self-examination. Staff manner, privacy and cost were the most common contributing factors for respondent's desire for future use of the screening service. Respondents showed a preference for doctors (70%) over nurses (30%), and females (80%) over males (20%) as their service providers. The findings suggest the need to disseminate appropriate information on screening services among the public to dispel misconceptions about the preference for doctors over nurses and females over males. Improving clinician- and other staff-patient communication would be important for breast and cervical screening programs in Hong Kong.

Adult↗
PubMed2001

Whole blood mercury concentrations in sub-fertile men in Hong Kong.

We aimed to investigate the association between whole blood mercury concentrations and semen quality in sub-fertile men. Fifty-nine male partners of infertile couples attending the Assisted Reproduction Unit of the Chinese University of Hong Kong between 1997 and 1998 were recruited into our study. Blood was taken from each subject for whole blood mercury concentration and hormone profile. Semen samples were obtained for computer assisted semen analysis using the Hobson sperm tracker. The semen parameters and hormone profile were compared between subjects with normal and those with elevated mercury concentrations. Twenty-one subjects (35.6%) had a whole blood mercury concentration higher than the normal range (0-50 nmol/l). All parameters of the semen analysis including the concentration of sperm, percentage of morphologically normal sperm, percentage of motile sperm, curvilinear velocity, straight-line velocity, average path velocity, and amplitude of lateral head displacement, were reduced in those with elevated blood mercury concentrations, although the difference was not statistically significant. We failed to demonstrate a statistically significant effect on the measurement of semen quality, but other adverse effects cannot be excluded. From a public heath perspective, these findings confirm that mercury toxicity is a potentially serious problem affecting the local community.

Adult↗
PubMed2001

Risk and prediction of preterm delivery in pregnancies complicated by antepartum hemorrhage of unknown origin before 34 weeks.

OBJECTIVE: To assess the timing and risk factors of preterm delivery in pregnancies complicated by antepartum hemorrhage of unknown origin (APHUO) before 34 weeks of gestation, and to formulate a clinical management protocol. METHODS: A retrospective study involving singleton pregnancies with APHUO occurring before the 34th week of gestation was performed over a 4-year period at a university teaching hospital. RESULTS: Seventy-five cases were identified. Fifty-nine (78.7%) did not have any associated uterine contractions, 74.7 and 90.7% of the cases were classified as having mild bleeding according to history and physical examination, respectively. The number of cases delivering before 37 weeks of gestation and before 34 weeks were 28 (37.3%) and 22 (29.3%), respectively. Eighteen cases (24%) delivered within the first week of APHUO, and 4 (5.3%) within the first day. The number of cases delivering within the first week was significantly higher when there were uterine contractions (62.5 vs. 13.6%, p < 0.001). The severity of bleeding was not shown to be related to the time of delivery. CONCLUSION: APHUO that occurs before 34 weeks is associated with a high risk of preterm delivery before 34 weeks (29.3%). The chance of delivery within the first week is 62.5% when there are coexisting uterine contractions. Even if contractions are absent, the risk is still high (13.6%) and persists beyond the first week. We suggest that this group of patients should be managed with a course of steroid injection and hospitalization for 4 days.

Female↗
PubMed2000

Effect of external cephalic version at term on fetal circulation.

OBJECTIVE: We sought to investigate the subclinical effect of external cephalic version on fetal circulation. STUDY DESIGN: A prospective observational study was conducted on 136 subjects who had external cephalic version at or beyond 36 weeks of gestation without clinical complication. Doppler ultrasonographic studies of the umbilical and middle cerebral circulations were performed before and after the external cephalic version. The following Doppler indexes were measured: (1) the pulsatility index of the umbilical artery, which represents disturbance of placental circulation, and (2) the pulsatility index of the fetal middle cerebral artery, which represents fetal response. The Wilcoxon signed rank test was used for all statistical analyses. RESULTS: There was no significant difference in pulsatility index of the umbilical artery before and after external cephalic version (P =.674). There was a statistically significant reduction in the pulsatility index of the middle cerebral artery after external cephalic version (P =.043), and this difference existed only among multiparous women (P =.029), among those in whom the external cephalic version was considered to be difficult (P =.038), and when the placenta was posteriorly located (P =.028). The reduction in pulsatility index was not related to whether the external cephalic version was successful. In all cases the Doppler indexes remained within the normal ranges, and there were no associated fetal complications. CONCLUSION: External cephalic version was not associated with any significant disturbance of placental resistance to blood flow. Conversely, external cephalic version was associated with a significant reduction in the pulsatility index of the middle cerebral circulation, especially among the multiparous women, after a difficult procedure or in those with a posterior placenta. This probably represents a normal fetal physiologic response to manipulation of the fetal head.

Bradycardia↗
PubMed2000

Cell-free fetal deoxyribonucleic acid in maternal circulation as a marker of fetal-maternal hemorrhage in patients undergoing external cephalic version near term.

OBJECTIVE: Our aim was to investigate whether external cephalic version performed near term increases the concentration of cell-free fetal deoxyribonucleic acid in maternal plasma. STUDY DESIGN: Forty-five patients who had singleton male fetuses and were undergoing external cephalic version at or beyond 36 weeks of gestation were recruited during a 20-month period. Maternal venous blood samples were taken before and within 10 minutes after external cephalic version. Deoxyribonucleic acid was extracted from the plasma samples. The amount of fetal deoxyribonucleic acid was quantified by means of the SRY gene on the Y chromosome as a fetal marker. The change in SRY gene concentration before and after external cephalic version was compared by paired sample t test. RESULTS: There was a significant increase in the concentration of fetal deoxyribonucleic acid in maternal serum after external cephalic version (before, 296 +/- 209 copies per milliliter; after, 369 +/- 228 copies per milliliter; P =.014). This increase in the concentration of deoxyribonucleic acid was most profound among the nulliparous patients after a successful version and in the presence of a posterior placenta. The location of the placenta was found to be the most significant factor accounting for the change in the deoxyribonucleic acid concentration. CONCLUSIONS: External cephalic version near term imposed a significant disturbance to the maternalplacental interface. Fetal deoxyribonucleic acid is a sensitive marker that is useful in the assessment of subclinical fetal-maternal hemorrhage.

Adult↗
PubMed2000

Thyroid function and psychiatric morbidity in patients with manic disorder receiving lithium therapy.

Euthyroid hyperthyroxinemia as a result of a transient increase in thyroid-stimulating hormone (TSH) levels may contribute to the development of manic disorder. Lithium has a potent short-term antithyroidal effect that may account for its antimanic action. The thyroid function and psychiatric morbidity of 46 adult patients with manic disorder were assessed prospectively before and 1 and 6 months after lithium treatment. At baseline, the free thyroxine level (FT4, 16.23 +/- 3.11 pmol/L) was at the high end of the normal range, whereas the free triiodothyronine (FT3, 4.24 +/- 0.65 pmol/L) and TSH (1.47 +/- 0.73 mIU/L) levels were within the normal range. All patients were clinically euthyroid, but five of them (11%) had elevated FT4 levels. Baseline FT3 and FT4 levels were positively correlated with past psychiatric morbidity. The FT4 level at baseline and after 1 month of treatment was positively correlated with scores on the Brief Psychiatric Rating Scale (p < 0.02) and negatively correlated with scores on the Global Assessment Scale (p < 0.005). During the first month of treatment, the reduction of FT3 and FT4 levels was significantly correlated with a decrease in psychiatric symptoms. By 6 months, the FT3 level was no longer significantly different from that at the baseline, but FT4 levels remained significantly lower. The TSH level increased progressively from baseline to 6 months. Multilevel models showed that FT4 and serum lithium levels were positively and negatively associated with psychiatric symptoms, respectively. The findings of the study lend support to the notion that euthyroid hyperthyroxinemia contributes to acute mania and suggest that lithium's short-term antimanic action may be mediated by its antithyroid effect.

Adult↗
PubMed2000

Outcome of labour after successful external cephalic version at term complicated by isolated transient fetal bradycardia.

OBJECTIVES: To investigate factors associated with the occurrence of transient fetal bradycardia after external cephalic version, and labour outcome after isolated transient fetal bradycardia. DESIGN: Cohort study. SETTING: Teaching hospital with a policy of offering external cephalic version for breech presentation at or beyond 36 weeks of gestation. POPULATION: Four hundred and twenty-nine external cephalic versions performed over a 5-year period. METHODS: Between group differences were compared with the unpaired t test or the chi2 test. Logistic regression analysis was performed to exclude confounding effects. MAIN OUTCOME MEASURES: Incidence of caesarean section for fetal distress. RESULTS: Transient fetal bradycardia occurred in 8.4% of external cephalic versions, and was associated with a successful version (OR 16.45, P < 0.001), a difficult procedure (OR 3.70, P = 0.001), and nulliparity (OR 2.83, P = 0.007). The incidence of intrapartum caesarean section for fetal distress was 16.7% in pregnancies with transient fetal bradycardia, compared with 7.9% in those without (OR 2.34, 95% CI 0.81, 6.71). CONCLUSIONS: Transient fetal bradycardia after external cephalic version may be associated with a higher risk of intrapartum caesarean section for fetal distress.

Bradycardia↗
PubMed2000

A survey of pregnant women's attitude towards breech delivery and external cephalic version.

A structured interview survey was carried out in 150 women who came for their first antenatal visit in a university hospital in Hong Kong between June and July 1998. Their opinions and perceptions of fetal and maternal safeties on different modes of delivery for both cephalic and breech presentation, and external cephalic version (ECV) were surveyed. Their decisions on the management of term breech-presenting pregnancy were examined. Most women (92%) preferred vaginal delivery to Caesarean delivery (CS) in case of cephalic presentation, mainly because it was a natural way of parturition. They perceived that vaginal delivery was safer than CS for both mothers and babies, but the reverse was true for breech presentation. About 82% chose ECV as the first choice of managing breech presentation, mainly because a successful version allowed a natural way of delivery. Only 2% of women considered ECV ineffective, and 13.3% and 18.7% considered it not safe for mothers and fetuses respectively. Therefore, ECV should be an available option in all obstetric units. Adequate counselling and explanation would improve the acceptance of ECV.

Attitude to Health↗
PubMed2000

Small bowel herniation through subumbilical port site following laparoscopic surgery at the time of reversal of anesthesia.

Incisional hernias through laparoscopic trocar sites are unusual complications of laparoscopy. Two cases of small bowel herniation at subumbilical port site occurred at the time of withdrawal of the trocar sheath at the end of the laparoscopic procedure are reported. The herniations were precipitated by the coughing movements of the patients as a result of too early reversal of the general anesthesia. Awareness of the complication, precaution at time of sheath withdrawal and a well-timed reversal of the general anesthesia are important in avoiding such a complication.

Adult↗