BackgroundDespite the non-invasive nature of non-invasive prenatal testing (NIPT), there is still a need for a separate informed consent process before testing. The objectives of this study are to assess (a) knowledge and preferences of Chinese women in a major public hospital in Hong Kong who underwent NIPT, and (b) whether their knowledge and preferences differ depending on womens’ characteristics and sources of information.MethodsSetting: prenatal diagnosis and counselling clinic.Between February 2012 and September 2013, a questionnaire survey was distributed to all women who underwent NIPT after positive aneuploidy screening. As a pilot study, ten knowledge questions were designed based on the rapid response statement on Prenatal Detection of Down Syndrome using Massively Parallel Sequencing from the International Society for Prenatal Diagnosis in 2011. The source of women’s knowledge and their preferences were also evaluated. While conventional screening was publicly funded, NIPT was not. Differences between subgroups were compared using chi square tests and logistic regression analysis.ResultsOf 152 women who underwent NIPT, 135 (88.8 %) completed their questionnaires. More than 90 % of women recognised the possibility of false positive and false negative results. Slightly more than 70 % of women knew the inferior sensitivity of NIPT compared to an invasive test, and the possibility of an uninformative test result, but were not aware of the complicated aspects of NIPT. Pregnant women with an advanced level of education or those who underwent NIPT before 15 weeks provided answers that was more accurate by around 10-20 % in two to three knowledge questions than those without. These associations were confirmed by multivariate logistic regression analysis. The women received information on NIPT largely from their private doctors (47.4 %) and web (41.5 %). In their future pregnancies, more women would opt for NIPT (a self-financed item) after positive screening (‘free’ in a public hospital) (57.8 %) than as a primary screening (30.4 %).ConclusionsIt is feasible to use a questionnaire based on the ISPD statement on NIPT to assess women’s knowledge of the test. The Chinese women who underwent NIPT recognised the limitations, but did not understand the complicated aspects. More information should be provided by health care professionals in order to facilitate an informed choice by patients. More women preferred NIPT as a contingent test than as a primary screening probably because of its high cost.

Objectives: To investigate how the introduction of noninvasive prenatal testing (NIPT) influenced women's testing choices following a positive Down syndrome screening. Methods: A retrospective study was conducted to compare differences in the uptake rates of invasive prenatal diagnosis (IPD) or no testing in one public hospital 1 year before (pre-NIPT) and 1 and 2 years after the introduction of NIPT in private in August 2011 using descriptive analysis and a χ² test. Conventional screening was funded publicly, but NIPT was not. Multivariable binary logistic regression was used to determine factors affecting choices. Results: In pre-NIPT and in years 1 and 2 after the introduction of NIPT, 306, 362 and 401 women who screened positive were seen, respectively. In year 1 and year 2, 12.6 and 26.7% of them underwent NIPT while IPD was decreased by 16.3 and 25.6%, respectively (p < 0.001). Both chorionic villus sampling and amniocentesis decreased in year 1, but only the former in year 2. However, the rate of declining further testing was similar before and after NIPT (p = 0.213). In multivariable analysis, first trimester screening, nulliparity and working women were significant predictors of accepting NIPT, while only nulliparity was a predictor of declining IPD (OR = 0.61). Conclusions: Introduction of NIPT resulted in a significant decrease in IPD for 2 consecutive years.

305Objectives To identify factors affecting the sex ratio at birth.Design Cross-sectional study.Setting Obstetric department of a public hospital in Hong Kong. Trend of sex ratio at birth in a public hospital in Hong Participants