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Biomedical subjects

Chin Peng Lee

Publications and source records attributed to Chin Peng Lee.

15 recordsLinked to original sources

First-trimester fetal limb biometry in Chinese population.

OBJECTIVES: To establish reference ranges for fetal limb biometry obtained by transabdominal ultrasound examination at 12-14 weeks of gestation in Chinese women. METHODS: A total of 1489 normal singleton fetuses between 12(+0) and 14(+6) weeks of gestation were examined transabdominally by two experienced observers. The gestation was ascertained by measurement of fetal crown-rump length (CRL) or biparietal diameter (BPD) and head circumference (HC). The lengths of the humerus and femur were prospectively worked out. RESULTS: Gestation-specific reference ranges for limb measurements were calculated. The femur length (FL) (mean +/- SD) was 9.15 +/- 1.44 mm at 12-12(+6) weeks, 11.45 +/- 1.35 mm at 13-13(+6) weeks, and 13.64 +/- 1.60 mm at 14-14(+6) weeks; the corresponding humerus length (HL) (mean +/- SD) was 9.63 +/- 1.44 mm, 12.01 +/- 1.41 mm, 14.29 +/- 1.48 mm, respectively. CONCLUSIONS: There was a general increase in fetal limb biometry with gestation. Fetal limb length can be an early marker of early growth restriction as well as fetal skeletal dysplasia among women in the local population.

Adult↗

Sonographic features of hemivertebra at 13 weeks' gestation.

Hemivertebra is a rare congenital spinal disorder where only one side of the vertebral body develops, leading to deformation of the spine, such as scoliosis or kyphosis. Previous reports suggest that the diagnosis may be based on antenatal sonographic examination after 14 weeks. We present the sonographic features of a fetus with solitary hemivertebra at 13 weeks' gestation confirmed by postmortem babygram, magnetic resonance imaging (MRI) and pathological examination. It shows that the condition may manifest in the first trimester of pregnancy.

Abortion, Eugenic↗

First-trimester examination of fetal nasal bone in the Chinese population.

OBJECTIVES: Absence of the nasal bone in fetuses with trisomy 21 is a potential ultrasound marker for Down syndrome from the first trimester onwards. Racial differences in fetal nasal bone length have been reported. There was no reference range for the first-trimester fetal nasal bone length (NBL) in the Chinese population. METHODS: From January 2002 to February 2005, we investigated the reference range of NBL in 2169 singleton fetuses whose parents were Chinese with normal pregnancy outcome. Ultrasound measurements of NBL were performed on a midsagittal plane at 12-14 weeks' gestation. RESULTS: The nasal bone length measurement showed a significant increase with gestational age (GA) (p < 0.05). A linear relationship between nasal bone length and gestational age (NBL = -3.3462 x GA + 0.627, R(2) = 0.30, p < 0.001) as well as a linear relationship between nasal bone length and crown-rump length (CRL) (NBL = 0.3741 x CRL + 0.284, R(2) = 0.30, P < 0.001) was established. CONCLUSION: The measurement of nasal bone length was feasible in the first trimester. The reference range of NBL in normal Chinese fetuses in the first-trimester of pregnancy was established. This formed a basis for further study on the use of fetal nasal bone measurement in the screening for aneuploidy in the Chinese population.

Adolescent↗

Human chorionic gonadotropin and plasma protein-A in alpha0-thalassemia pregnancies.

OBJECTIVE: Maternal serum free beta-human chorionic gonadotropin (beta-hCG) and pregnancy-associated plasma protein-A (PAPP-A) have been used effectively in the screening of Down syndrome in the first trimester. In this study, we aim to measure the value of first-trimester maternal serum free beta-hCG and PAPP-A as predictors of homozygous alpha0-thalassemia-affected pregnancies. METHODS: Free beta-hCG and PAPP-A concentrations were measured in stored maternal serum samples obtained at 12 weeks of gestation from 22 women with fetuses affected by homozygous alpha0-thalassemia and from 436 controls matched for maternal age, ethnicity, and weight, as well as gestation at blood sampling. RESULTS: Maternal serum concentration of free beta-hCG was significantly increased in women with pregnancies affected by homozygous alpha0-thalassemia than in controls (P = .001). Concentrations of PAPP-A did not differ between the cases affected by homozygous alpha0-thalassemia and the controls (P = .652). CONCLUSION: Pregnancies affected by homozygous alpha0-thalassemia are associated with increased maternal serum free beta-hCG at 11-14 weeks of gestation. This serum analyte alone may not be clinically useful as a predictor of pregnancies affected by homozygous alpha0-thalassemia. However, the absence of ultrasound features of fetal anemia and hydropic changes, together with normal maternal serum free beta-hCG and PAPP-A in the first trimester, will be reassuring signs of normality for fetuses at risk of homozygous alpha0-thalassemia and, hence, enable women to avoid invasive tests in unaffected pregnancies.

Adult↗

Nuchal translucency in pregnancies conceived after assisted reproduction technology.

PURPOSE OF REVIEW: Nuchal translucency is one of the important markers in the first trimester during antenatal screening for fetal Down's syndrome. With the observation of alterations in biochemical markers in pregnancies conceived after assisted reproduction, this review presents current information related to the thickness of nuchal translucency in these pregnancies. RECENT FINDINGS: Early small studies did not demonstrate any discrepancy in the thickness of nuchal translucency in fetuses from assisted reproduction and from spontaneous pregnancies, but there has been recent evidence to suggest an increased level of nuchal translucency in singletons from various modes of assisted-reproduction technology. Nuchal translucency in twins following assisted reproduction did not, however, show a similar increase. Although the effect of chorionicity was not specifically addressed, nuchal translucency thickness in twins born after assisted reproduction was reported to be comparable to that in spontaneous singletons. It is possible that singletons and twins after assisted reproduction exhibit different antenatal behavior and pregnancy courses. SUMMARY: Similar to other biochemical markers of fetal Down's syndrome, nuchal translucency is increased in singletons after assisted-reproduction technology. Further studies on twin pregnancies, in particular dichorionic twins, are necessary before conclusive evidence can be drawn for multiple pregnancies.

Down Syndrome↗

Sonographic features of lethal multiple pterygium syndrome at 14 weeks.

Lethal multiple pterygium syndrome is a rare inherited disorder. Previous reports suggest that the diagnosis may be based on prenatal sonographic demonstration of severe limb flexion, absence of fetal motion, and a large cystic hygroma in the second and third trimesters. We present the sonographic features and postmortem features of a fetus with lethal multiple pterygium syndrome at 13 weeks of gestation, which shows that the condition can possibly be diagnosed in the first trimester of pregnancy.

Abnormalities, Multiple↗

Mild postnatal anemia: is it a problem?

Mild postnatal anemia is common. However, determination of postnatal hemoglobin level or iron supplementation are not routine in many obstetric units. This study was designed to evaluate the impact of mild postnatal anemia and iron supplementation on women. One hundred fifty women who had postnatal hemoglobin levels between 80 and 99 g/L were randomly assigned into two groups with iron tablets or placebo provided from the time of diagnosis until reassessment at 6 weeks. The patients' general well-being, hemoglobin levels, iron status, side effects, and compliance were assessed. One hundred twenty-two women returned for reassessment. Twelve (9.8%) of the 122 women recruited and four (3.2%) of 122 nonanemic matched controls complained of dizziness 2 days after delivery; the difference was statistically significant (chi2 test, p<0.05). At 6 weeks postpartum, significantly more women were anemic (chi2 test, p<0.05) and iron deficient (chi2 test, p<0.01) in the placebo group. The score of general well-being as assessed by a 4-point scale was significantly higher in the iron supplementation group (Mann-Whitney test, p<0.05). The amounts of drugs consumed in both groups were comparable and the incidences of side effects were similar.

Adult↗

Pilot study on the midsecond trimester examination of fetal nasal bone in the Chinese population.

OBJECTIVES: Hypoplasia of the nasal bone of fetuses affected by trisomy 21 and other aneuploidies could be detected by prenatal ultrasound examination and was an important new marker in the detection of Down syndrome in the second trimester. Racial differences in fetal nasal bone length have been reported. However, there was no reference range for the fetal nasal bone length (NBL) in the Chinese population. We conducted a pilot study to investigate the reproducibility of the measurement of fetal NBL in the mid second trimester and to determine whether there is any difference in NBL between the Chinese and the Caucasian population. METHODS: From June 2002 to February 2003, 198 Chinese women were examined. Ultrasound measurements of NBL were performed on a strictly midsagittal plane in normal singleton fetuses at 15 to 23 weeks' gestation. RESULTS: The mean difference in the NBL between the two investigators was small (mean = 0.043 mm; 95% CI, -0.033 to 0.12), and there was substantial agreement between the measurements for each observer. Limits of agreement were -0.48 to 0.35 and -0.29 to 0.22 mm in the two investigators respectively. It was found that the median length of the nasal bones increased from 3.5 mm at 15 weeks to 6.7 mm at 23 weeks' gestation. There was a linear relationship between the length of the nasal bone and the gestational age. CONCLUSION: It was demonstrated that the measurement of nasal bone length was feasible and reproducible in the second trimester. The fetal nasal bone length in Chinese population appeared shorter than that of Caucasian and African-Americans. There is a need to establish a reference range of fetal NBL for the Chinese population.

Adolescent↗

Ultrasound screening of fetal structural abnormalities at 12 to 14 weeks in Hong Kong.

OBJECTIVE: Ultrasound screening for fetal abnormalities is conventionally performed at 18 to 20 weeks of gestation. Recent data suggested that many fetal structural abnormalities could be detected by ultrasound examination at 12 to 14 weeks of pregnancy. In this study, we investigated the effectiveness of early ultrasound examination in the detection of fetal abnormalities in women aged 35 years or older. METHODS: From February 1998 to March 2001, pregnant women aged 35 or above were examined by transabdominal and transvaginal sonography between 12 and 14 weeks of gestation. If the anatomical survey was normal, the women underwent routine 16- to 20-week ultrasound examination. Pregnancy outcome was obtained from the hospital records or by contacting the subjects. RESULTS: Twenty-six of the 1609 fetuses had structural abnormalities. Fourteen were detected at the ultrasound examination at 12 to 14 weeks. Detection rate was 53.8% (14/26; 95% CI 44, 64) with a false-positive rate of 0.3% (5/1583; 95% CI 0.16, 0.44). Six additional abnormalities (23.1%, 6/26) were detected at 16- to 20-week ultrasound examination. The overall detection rate of structural abnormalities was 76.9% (20/26; 95% CI 68.6, 85.2). CONCLUSIONS: The effectiveness of ultrasound examination at 12 to 14 weeks to screen for fetal abnormalities approached that achieved at 20 weeks and can be a good adjunct to the conventional examination.

Adult↗

First-trimester diagnosis of hydrolethalus syndrome in a Chinese family.

We report a case resembling hydrolethalus syndrome in a Chinese family. Fetal polydactyly, syndactyly, encephalocele and cardiac malformation were detected on ultrasound examination at 12 weeks' gestation. Termination of pregnancy was performed, and postmortem examination confirmed the findings. This is the first report of a first-trimester prenatal diagnosis of hydrolethalus syndrome in the Chinese population.

Adult↗

Universal SARS preventive measures in an obstetrics unit: experience of health care staff.

BACKGROUND: Severe acute respiratory syndrome (SARS) epidemics have affected populations in many countries, including Hong Kong. This disease is infectious, especially in hospital settings. Health care workers have expressed great concern, including those working in obstetrics wards, defined as high-risk areas. METHOD: Four weeks after implementation of universal precautionary measures at a teaching hospital in Hong Kong, a survey of the health care staff was conducted to identify their feelings and opinions. RESULTS: In spite of general knowledge about SARS epidemics and related mortality, most respondents stated that universal precautionary measures were not very necessary, especially in the obstetrics ward. In addition, respondents were generally dissatisfied with the measures, as most items imposed extra work, inconvenience, and burdens on the staff. CONCLUSION: Our findings reported the views and satisfaction levels of the front-line staff of an obstetric unit concerning precautionary measures against SARS. The importance of individualized design and implementation of infection control measures is highlighted and discussed.

Adult↗

The effect of ethnic origin on nuchal translucency at 10-14 weeks of gestation.

INTRODUCTION: Fetal nuchal translucency (NT) increases with gestation and is affected by fetal posture and fetal gender. A recent report suggested that there might also be ethnic differences. We investigated the effect of ethnic origin on NT in an Asian population. METHODS: NT was measured at 10-14 weeks. The measurements were converted into multiples of the median (MoM) for gestational day. The risk of Down syndrome was calculated by combining NT and maternal age. Cases affected by chromosomal and major structural abnormalities were excluded. NT measurements of different ethnic groups were compared. RESULTS: Between January 1997 and October 2001, 16 981 pregnancies with known ethnic origin and normal fetal outcome were analysed. Median NT MoM (95% CI) of the Filipinos was 1.07 (1.04-1.11). This was significantly higher than that of the Chinese, 1.01 (1.01-1.02); other Asians (Indians, Pakistanis and Nepalese), 0.96 (0.94-0.99), and Caucasians, 0.98 (0.93-1.06) (p<0.05, respectively; Mann-Whitney U-test). An NT risk cut-off of 1:180 would classify 5% of the Chinese, 4.6% of the Caucasians, 5.6% of the Filipinos and 4.2% of the other Asians as screen-positive. There were no statistically significant differences between these screen-positive rates (p>0.05, Chi-square test). CONCLUSIONS: Although there were statistically significant differences in NT measurements between different ethnic groups, it was clinically insignificant, as reflected by similar screen-positive rates.

Adult↗

Comparison and integration of first trimester fetal nuchal translucency and second trimester maternal serum screening for fetal Down syndrome.

BACKGROUND: It is uncertain whether first trimester nuchal translucency (NT) is more effective than the well-established second trimester serum screening for fetal Down syndrome or whether their combination works best. We report data from a large multicentre non-interventional trial in which all subjects underwent both first and second trimester screening. METHODS: All women who attended the obstetric clinic before 15 weeks' gestation were recruited. An ultrasound examination was performed at 10 to 14 weeks to measure the NT. The nuchal measurements were not acted upon unless the fetus showed gross features of hydrops fetalis. All women had serum alpha-fetoprotein (AFP) and human chorionic gonadotrophin (hCG) assay at 15 to 20 weeks. The Down syndrome risk assigned by serum screening was disclosed and amniocentesis was offered if this assigned risk was >or=1:250 or if the women were 35 years and older. The efficacy of different combinations of screening markers was compared. RESULTS: Between January 1997 and August 2000, 17 590 women were recruited (19% >or=35 years old). After excluding subjects who miscarried, defaulted the serum test and other reasons, 16 237 pregnancies were analysed. Of these, 35 pregnancies were affected by Down syndrome (2.2 cases per 1000 pregnancies). At a false-positive rate of 5%, the detection rate of Down syndrome by NT alone, NT and age, serum hCG, AFP and age, and NT, hCG, AFP and age were 61%, 69%, 73% and 86%, respectively. CONCLUSION: Integration of NT and second trimester serum AFP and hCG assay yielded the best screening efficacy for Down syndrome.

Amniocentesis↗

Sonographic features of ileal duplication cyst at 12 weeks.

Enteric duplication cyst is a congenital abnormality that is believed to arise from abnormal recanalization of the bowel during embryogenesis. Previous reports suggest that the condition may be suspected prenatally by sonographic demonstration of an intra-abdominal cystic mass in the second and third trimesters. We present the sonographic features of a fetus with ileal duplication cyst at 12 weeks of gestation, which show that the condition may present in the first trimester of pregnancy.

Adult↗