Oi Ka Chan

Trends in maternal obesity and associated risks of adverse pregnancy outcomes in a population of Chinese women.

Objective  To assess the effect of increasing body mass index (BMI) on pregnancy outcome in a population of Chinese women.

Fetal crown–rump length and estimation of gestational age in an ethnic Chinese population

To develop a sonographic dating formula based on fetal crown–rump length (CRL) in a Hong Kong Chinese population, quantify its systematic prediction error and compare its performance with established dating formulae.

Outcome of induction of labour using maternal characteristics, ultrasound assessment and biochemical state of the cervix.

Objective. To assess pre-induction sonographic, digital examination and biochemical changes in the cervix to predict induction outcome. Methods. Transvaginal and abdominal scans were performed in 460 women at 37–41 weeks of gestation to determine cervical length (CL), posterior cervical angle (PCA) and foetal occipital position. The Bishop Score (BS) and the absence/presence of phosphorylated form of insulin-like growth factor-binding protein-1 (phIGFBP-1) in cervical secretions were assessed. Independent parameters significantly associated with a vaginal delivery were identified. Results. A total of 340 (73.9%) women achieved a vaginal delivery following induction. Multivariate analysis indicated that significant independent predictors of vaginal delivery were CL (adjusted odds ratio [AOR]: 0.59, 95% confidence interval [CI]: 0.45–0.79), PCA (AOR: 1.89, 95% CI: 1.09–3.28) and multiparae (AOR: 10.02, 95% CI: 5.10–19.69). For a specificity of 75%, the sensitivity for prediction of vaginal delivery using the BS, the CL and the multivariate model using the identified significant independent predictors were 37.1, 46.8 and 68%, respectively. Conclusion. The combination of sonographic assessment of the cervix and maternal characteristics was superior to the either BS or CL alone in the prediction of the induction outcome. Inclusion of the absence/presence of phIGFBP-1 did not further improve induction outcome.

Systematic identification of spontaneous preterm birth-associated RNA transcripts in maternal plasma.

Background Spontaneous preterm birth (SPB, before 37 gestational weeks) is a major cause of perinatal mortality and morbidity, but its pathogenesis remains unclear. Studies on SPB have been hampered by the limited availability of markers for SPB in predelivery clinical samples that can be easily compared with gestational age-matched normal controls. We hypothesize that SPB involves aberrant placental RNA expression, and that such RNA transcripts can be detected in predelivery maternal plasma samples, which can be compared with gestational age-matched controls. Principal Findings Using gene expression microarray to profile essentially all human genes, we observed that 426 probe signals were changed by >2.9-fold in the SPB placentas, compared with the spontaneous term birth (STB) placentas. Among the genes represented by those probes, we observed an over-representation of functions in RNA stabilization, extracellular matrix binding, and acute inflammatory response. Using RT-quantitative PCR, we observed differences in the RNA concentrations of certain genes only between the SPB and STB placentas, but not between the STB and term elective cesarean delivery placentas. Notably, 36 RNA transcripts were observed at placental microarray signals higher than a threshold, which indicated the possibility of their detection in maternal plasma. Among them, the IL1RL1 mRNA was tested in plasma samples taken from 37 women. It was detected in 6 of 10 (60%) plasma samples collected during the presentation of preterm labor (≤32.9 weeks) in women eventually giving SPB, but was detected in only 1 of 27 (4%) samples collected during matched gestational weeks from women with no preterm labor (Fisher exact test, p = 0.00056). Conclusion We have identified 36 SPB-associated RNA transcripts, which are possibly detectable in maternal plasma. We have illustrated that the IL1RL1 mRNA was more frequently detected in predelivery maternal plasma samples collected from women resulting in SPB than the gestational-age matched controls.

Knowledge on hepatitis B infection among pregnant women in a high endemicity area

OBJECTIVE To assess the knowledge on hepatitis B virus (HBV) infection and associated factors among expectant mothers in an endemic region. METHODS A questionnaire was administered to pregnant Chinese women (n=1623) attending the antenatal clinic to examine their knowledge on HBV infection, and correlating this with socio-demographic, medical and obstetric factors. RESULTS Independent factors associated with insufficient reduced HBV knowledge include women outside the healthcare sector, lower education level, and no previous HBV testing. The majority of respondents could provide correct responses about the common aspects of HBV infection, including screening, blood-borne and perinatal transmissions, prevention by vaccination, and sequelae of HBV infection, but 47.1% did not know that HBV is transmissible by sexual intercourse. Over 75% respondents misunderstood the fact that HBV cannot be transmitted through food, or prevented by a balanced life style and nutrition. CONCLUSIONS Misconceptions about HBV transmission are still common among the obstetric population, and the provision of appropriate and correct information is warranted to improve further the control of HBV infection to the target group. PRACTICE IMPLICATIONS Appropriate emphasis should be given to educating the general population about horizontal transmission of HBV.

Nausea and vomiting in health-related quality of life among Chinese pregnant women

Background:  Nausea and vomiting in pregnancy (NVP) is the most common pregnancy complication affecting women during the first trimester of pregnancy. The cause of NVP remains unknown and factors associated with the occurrence of NVP are contradictory. There is currently little information on its effects of NVP in general and specifically in the Chinese population.

First‐trimester fetal nasal bone length in an ethnic Chinese population

To determine reference ranges of fetal nasal bone length (NBL) in a Chinese population and to assess the value of NBL measurement in screening for chromosomal defects in the first trimester.

Chinese women's preferences for prenatal diagnostic procedure and their willingness to trade between procedures.

To assess Chinese womens preference for the choice of a prenatal diagnosis test, karyotyping or rapid aneuploidy, and its relationship to maternal psychological state.

Determinants of hepatitis B vaccine uptake among pregnant Chinese women in Hong Kong.

To determine the prevalence of a history of hepatitis B vaccination among pregnant Chinese women in Hong Kong, and to identify factors associated with vaccine uptake at their own expense.

Miscarriage after invasive prenatal diagnostic procedures: how much risk our pregnant women are willing to take?

To elicit the level of risk of prenatal diagnostic procedure‐related miscarriage that Chinese pregnant women were willing to accept.