Longitudinal evaluation of cervical length and shear wave elastography in women with spontaneous preterm birth

OBJECTIVES

To compare longitudinal changes in cervical length (CL) and mean cervical shear wave elastography (CSWE) scores between women with singleton and twin pregnancies who experience spontaneous preterm birth (sPTB) and those who have term births (TB).

METHODS

This was a prospective longitudinal study of 1264 unselected women with singleton (n=1143) and twin (n=121) pregnancy attending a dedicated research clinic for screening of sPTB at 4 timepoints during pregnancy including 11-15+6 (visit 1), 16-20+6 (visit 2), 21-24+6 (visit 3) and 28-32+6 (visit 4) weeks of gestation. At each visit, a transvaginal ultrasound scan was conducted to measure the CL and the CSWE scores from six regions of interest (ROI) (inner, middle, and external parts of anterior and posterior lips) in the cervix. The mean of CSWE scores from the six ROIs were calculated for data analysis. Log10 transformation was applied to make the data Gaussian prior to statistical analysis. A multilevel mixed-effects analysis was performed to compare CL and CSWE longitudinally between sPTB and TB groups.

RESULTS

A total of 57 (4.99%) singleton pregnancies and 33 (27.27%) twin pregnancies were complicated with sPTB. Women with sPTB had shorter CL across gestation when controlling for history of cervical surgery, number of fetuses, gestational age at cervical assessment (GA), and the interaction between GA and sPTB. CL in the sPTB group was significantly lower than that of the TB group at 21-24+6 weeks (p=0.039) and 28-32+6 weeks (p<0.001). Twin pregnancies had significantly longer CL throughout pregnancy, compared to singleton pregnancies (coefficient=0.01864, p<0.001). Furthermore, after adjusting for maternal age, weight, height, body mass index (BMI), and GA, CSWE scores in sPTB group were significantly lower in the sPTB group across gestation, compared to the TB group (1.28265 vs 1.32832; p=0.013). However, in the individual visit analysis, CSWE scores in the sPTB group were significantly lower than that of the TB group only at 11-15+6 weeks (p=0.013). There was no difference in CSWE scores between singleton and twin pregnancies throughout pregnancy (coefficient=-0.00128, p=0.937).

CONCLUSION

Women with sPTB have shorter CL and softer cervix across gestation when compared to those with TB. In the individual visit analysis, the reduction in CL in the sPTB group occurs from late second trimester onwards, while the reduction in cervical stiffness in the sPTB group is observed primarily in the first trimester. Additionally, our study has found that CL is significantly shorter in singleton pregnancies compared to twin pregnancies, while cervical stiffness does not differ between the two types of pregnancy. Our findings indicate that the cervix tends to undergo a softening process prior to shortening in the sPTB cases This article is protected by copyright. All rights reserved.

Long-term trends in the incidence and management of shoulder dystocia in a tertiary obstetric unit in Hong Kong

INTRODUCTION

Because there have been changes in the management of macrosomic pregnancies and shoulder dystocia in the past decade, this study was conducted to compare the incidences of shoulder dystocia and perinatal outcomes between the periods of 2000-2009 and 2010-2019.

METHODS

This retrospective study was conducted in a tertiary obstetric unit. All cases of shoulder dystocia were identified using the hospital's electronic database. The incidences, maternal and fetal characteristics, obstetric management methods, and perinatal outcomes were compared between the two study periods.

RESULTS

The overall incidence of shoulder dystocia decreased from 0.23% (134/58 326) in 2000-2009 to 0.16% (108/65 683) in 2010-2019 (P=0.009), mainly because of the overall decline in the proportion of babies with macrosomia (from 3.3% to 2.3%; P<0.001). The improved success rates of the McRoberts' manoeuvre (from 31.3% to 47.2%; P=0.012) and posterior arm extraction (from 52.9% to 92.3%; P=0.042) allowed a greater proportion of affected babies to be delivered within 2 minutes (from 59.0% to 79.6%; P=0.003). These changes led to a significant reduction in the proportion of fetuses with low Apgar scores: <5 at 1 minute of life (from 13.4% to 5.6%; P=0.042) and <7 at 5 minutes of life (from 11.9% to 4.6%; P=0.045).

CONCLUSION

More proactive management of macrosomic pregnancies and enhanced training in the acute management of shoulder dystocia led to significant improvements in shoulder dystocia incidence and perinatal outcomes from 2000-2009 to 2010-2019.

Cost-effectiveness analysis of carbetocin for prevention of postpartum hemorrhage in a low-burden high-resource city of China

BACKGROUND

Postpartum hemorrhage (PPH) is a major cause of maternal morbidity, and oxytocin is the first-line uterotonic agent for PPH prevention. Clinical findings have reported carbetocin to reduce PPH risk without increasing risk of important side effects. Hong Kong is a low PPH burden and high-resource city in China. We aimed to examine the cost-effectiveness of PPH prevention with carbetocin from the perspective of Hong Kong public healthcare provider.

METHODS

A decision-analytic model was developed to simulate clinical and economic outcomes of carbetocin and oxytocin for PPH prevention in a hypothetical cohort of women at the third stage of labor following vaginal birth or Caesarean section (C-section). The model inputs were retrieved from literature and public data. Base-case analysis and sensitivity analysis were performed. The model time horizon was the postpartum hospitalization period. Primary model outcomes included PPH-related direct medical cost, PPH, hysterectomy, maternal death, and quality-adjusted life-year (QALY) loss.

RESULTS

In base-case analysis, carbetocin (versus oxytocin) reduced PPH-related cost (by USD29 per birth), PPH ≥500 mL and ≥1,500 mL (by 13.7 and 1.9 per 1,000 births), hysterectomy (by 0.15 per 1,000 births), maternal death (by 0.02 per 1,000 births), and saved 0.00059 QALY per birth. Relative risk of PPH ≥500 mL with carbetocin versus oxytocin, and proportion of child births by C-section were two influential parameters identified in deterministic sensitivity analysis. In probabilistic sensitivity analysis, carbetocin was accepted as cost-effective in >99.7% of the 10,000 Monte Carlo simulations at a willingness-to-pay threshold of zero USD/QALY.

CONCLUSION

PPH prevention with carbetocin appeared to reduce major unfavorable outcomes, and save cost and QALYs.

Neonatal mortality in singleton pregnancies: a 20-year retrospective study from a tertiary perinatal unit in Hong Kong

INTRODUCTION

The global neonatal death (NND) rate has been declining in recent decades, but there are no comprehensive data concerning the characteristics of NNDs in Hong Kong. This study investigated the trends and aetiologies of NNDs among singleton pregnancies in Hong Kong.

METHODS

This study included all cases of NND from singleton pregnancies in a tertiary hospital in Hong Kong between 2000 and 2019. The rates, clinical characteristics, and aetiologies of NND were compared between the first (2000-2009) and the second (2010-2019) decades.

RESULTS

The NND rate decreased from 1.66/1000 livebirths (97 cases) in the first decade to 1.32/1000 livebirths (87 cases) in the second decade. Congenital or genetic abnormalities (82 cases) caused 44.6% of all NNDs. There was a significant reduction from 0.82/1000 livebirths in the first decade to 0.52/1000 livebirths in the second decade (P=0.037). Other causes of NND were prematurity (69 cases; 37.5%), sepsis (16 cases; 8.7%), hypoxic-ischaemic encephalopathy (15 cases; 8.2%), and sudden infant death syndrome (2 cases; 1.1%). Gestational age-specific neonatal mortality for moderately preterm neonates (31-33 weeks of gestation) significantly decreased from 34.73/1000 in 2000-2009 to 8.63/1000 in 2010-2019 (P=0.001), but there were no significant changes in neonatal mortality for other gestations.

CONCLUSION

The NND rate in Hong Kong is among the lowest worldwide. Neonatal deaths in our centre declined over the past two decades, mainly because of improvements in the prenatal diagnosis and treatment of congenital or genetic abnormalities, as well as an improved survival rate among moderately preterm neonates.

The view of Hong Kong parents on secondary use of dried blood spots in newborn screening program

Background

Residual dried blood spots (rDBS) from newborn screening programmes represent a valuable resource for medical research, from basic sciences, through clinical to public health. In Hong Kong, there is no legislation for biobanking. Parents’ view on the retention and use of residual newborn blood samples could be cultural-specific and is important to consider for biobanking of rDBS.

Objective

To study the views and concerns on long-term storage and secondary use of rDBS from newborn screening programmes among Hong Kong Chinese parents.

Methods

A mixed-method approach was used to study the views and concerns on long-term storage and secondary use of rDBS from newborn screening programmes among Hong Kong Chinese parents of children 0–3 years or expecting parents through focus groups (8 groups; 33 participants) and a survey (n = 1012, 85% mothers) designed with insights obtained from the focus groups. We used framework analysis to summarise the themes as supportive factors, concerns and critical arguments for retention and secondary use of rDBS from focus group discussion. We used multiple logistic regression to assess factors associated with support for retention and secondary use of rDBS in the survey.

Results

Both in focus groups and survey, majority of parents were not aware of the potential secondary use of rDBS. Overall secondary use of rDBS in medical research was well accepted by a large proportion of Hong Kong parents, even if all potential future research could not be specified in a broad consent. However parents were concerned about potential risks of biobanking rDBS including leaking of data and mis-use of genetic information. Parents wanted to be asked for permission before rDBS are stored and mainly did not accept an “opt-out” approach. The survey showed that parents born in mainland China, compared to Hong Kong born parents, had lower awareness of newborn screening but higher support in biobanking rDBS. Higher education was associated with support in rDBS biobanking only among fathers.

Conclusion

Long-term storage and secondary use of rDBS from newborn screening for biomedical research and a broad consent for biobanking of rDBS are generally acceptable to Hong Kong parents given their autonomy is respected and their privacy is protected, highlighting the importance of an accountable governance and a transparent access policy for rDBS biobanks.

Perinatal mortality rate in multiple pregnancies: a 20-year retrospective study from a tertiary obstetric unit in Hong Kong

INTRODUCTION

Multiple pregnancies have become more common, but their perinatal mortality rate remains higher than the rate among singleton pregnancies. This retrospective study investigated the prevalence and causes of perinatal mortality among multiple pregnancies in Hong Kong.

METHODS

All multiple pregnancies in a university tertiary obstetric unit between 2000 and 2019 were reviewed, and the medical records of cases complicated by stillbirth and neonatal death were identified. The causes of perinatal mortality were determined based on clinical assessment and laboratory results, then compared between the first (2000-2009) and second (2010-2019) decades.

RESULTS

The prevalence of multiple pregnancies increased from 1.41% in the first decade to 1.91% in the second decade (P<0.001). Compared with the first decade, the second decade had a lower stillbirth rate (14.72 vs 7.68 [both per 1000 births]; P=0.026), late neonatal death rate (4.78 vs 1.16 [both per 1000 livebirths]; P=0.030), and total mortality rate (25.32 vs 13.82 [both per 1000 births]; P=0.006). The decline in stillbirth rate was related to improvements in antenatal care and treatment. The decline in the late neonatal death rate was related to a reduction in preterm birth before 34 weeks (18.5% vs 15.2%; P=0.006), as well as an improvement in the mortality rate in the subgroup of 31-33 weeks (19.23 vs 0 [both per 1000 livebirths]; P=0.035).

CONCLUSION

Although the prevalence of multiple pregnancies increased during the study period, the corresponding total perinatal mortality rate improved by 45.4%.

Impact of replacing or adding pregnancy-associated plasma protein-A at 11-13 weeks on screening for preterm pre-eclampsia

OBJECTIVE

To assess whether pregnancy-associated plasma protein-A (PAPP-A) alters or provides equivalent screening performance as placental growth factor (PlGF) when screening for preterm pre-eclampsia (PE) at 11-13 weeks of gestation.

METHODS

This was a secondary analysis of a non-intervention screening study of 6546 singleton pregnancies that were screened prospectively for preterm PE in the first trimester between December 2016 and June 2018. Patient-specific risks for preterm PE were estimated by maternal history, mean arterial pressure (MAP), uterine artery pulsatility index (UtA-PI), PlGF and PAPP-A. A competing-risks model with biomarkers expressed as multiples of the median was used. All women and clinicians were blinded to the risk for preterm PE. The performance of screening for preterm PE using PlGF vs PAPP-A vs both PAPP-A and PlGF was assessed by comparing areas under the receiver-operating-characteristics (AUC) curves. McNemar's test was used to compare detection rate at a fixed false-positive rate (FPR) of 10%.

RESULTS

PlGF and PAPP-A were measured in 6546 women, of whom 37 developed preterm PE. The AUC and detection rate at 10% FPR using PlGF in combination with maternal history, MAP and UtA-PI were 0.854 and 59.46%, respectively. The respective values were 0.813 and 51.35% when replacing PlGF with PAPP-A and 0.855 and 59.46% when using both PAPP-A and PlGF. Statistically non-significant differences were noted in AUC when replacing PlGF with PAPP-A (ΔAUC, 0.04; P = 0.095) and when using both PAPP-A and PlGF (ΔAUC, 0.002; P = 0.423). However, on an individual case basis, screening using PlGF in conjunction with maternal history, MAP and UtA-PI identified three (8.1%) additional pregnancies that developed preterm PE and that were not identified when replacing PlGF with PAPP-A. Screening using PAPP-A in addition to maternal history and other biomarkers did not identify any additional pregnancies.

CONCLUSION

On an individual case basis, adoption of a screening strategy that uses PAPP-A instead of PlGF results in reduced detection of preterm PE, consistent with previous literature. © 2022 International Society of Ultrasound in Obstetrics and Gynecology.

Non-visualisation of fetal gallbladder in a Chinese cohort

INTRODUCTION

Non-visualisation of fetal gallbladder (NVFGB) is associated with chromosomal abnormalities, biliary atresia, cystic fibrosis, and gallbladder agenesis in Caucasian fetuses. We investigated the outcomes of fetuses with NVFGB in a Chinese cohort.

METHODS

This retrospective analysis included cases of NVFGB among Chinese pregnant women at five public fetal medicine clinics in Hong Kong from 2012 to 2019. We compared the incidences of subsequent gallbladder visualisation, chromosomal abnormalities, biliary atresia, cystic fibrosis, and gallbladder agenesis between cases of isolated NVFGB and cases of non-isolated NVFGB.

RESULTS

Among 19 cases of NVFGB detected at a median gestational age of 21.3 weeks (interquartile range, 20.0-22.3 weeks), 10 (52.6%) were isolated and nine (47.4%) were non-isolated. Eleven (58.0%) cases had transient non-visualisation, four (21.0%) had gallbladder agenesis, three (15.8%) had chromosomal abnormalities (trisomy 18, trisomy 21, and 22q11.2 microduplication), one (5.2%) had biliary atresia, and none had cystic fibrosis. The incidence of serious conditions was significantly higher in the non-isolated group than in the isolated group (44.4% vs 0%; P=0.029); all three cases with chromosomal abnormalities and the only case of biliary atresia were in the non-isolated group, while all four cases with gallbladder agenesis were in the isolated group. The incidences of transient non-visualisation were similar (55.6% vs 60.0%; P=1.000).

CONCLUSION

Isolated NVFGB is often transient or related to gallbladder agenesis. While investigations for chromosomal abnormalities and biliary atresia are reasonable in cases of NVFGB, testing for cystic fibrosis may be unnecessary in Chinese fetuses unless the NVFGB is associated with consistent ultrasound features, significant family history, or consanguinity.

Exploring the diagnostic utility of genome sequencing for fetal congenital heart defects

OBJECTIVE

The diagnostic yield for congenital heart defects (CHD) with routine genetic testing is around 10-20% when considering the pathogenic CNVs or aneuploidies as positive findings. This is a pilot study to investigate the utility of genome sequencing (GS) for prenatal diagnosis of CHD.

METHODS

Genome sequencing (GS, 30X) was performed on 13 trios with CHD for which karyotyping and/or chromosomal microarray results were non-diagnostic.

RESULTS

Trio GS provided a diagnosis for 4/13 (30.8%) fetuses with complex CHDs and other structural anomalies. Findings included pathogenic or likely pathogenic variants in DNAH5, COL4A1, PTPN11, and KRAS. Of nine cases without a possibly genetic etiology by GS, we had follow-up on eight. For five of them (60%), the parents chose to keep the pregnancy. A balanced translocation [46,XX,t(14;22)(q32.33;q13.31)mat] was detected in a trio with biallelic DNAH5 mutations, which together explained the recurrent fetal situs inversus and dextrocardia that was presumably due to de novo Phelan-McDermid syndrome. A secondary finding of a BRCA2 variant and carrier status of HBB, USH2A, HBA1/HBA2 were detected in the trio.

CONCLUSIONS

GS expands the diagnostic scope of mutation types over conventional testing, revealing the genetic etiology for fetal heart anomalies. Patients without a known genetic abnormality indicated by GS likely opted to keep pregnancy especially if the heart issue could be repaired. We provide evidence to support the application of GS for fetuses with CHD. This article is protected by copyright. All rights reserved.

Chromosomal abnormalities and neurological outcomes in fetal cerebral ventriculomegaly: a retrospective cohort analysis

INTRODUCTION

This study investigated the incidences of chromosomal abnormalities and the neurological outcomes according to the degree of fetal cerebral ventriculomegaly.

METHODS

All women with antenatal ultrasound diagnosis of fetal cerebral ventriculomegaly were retrospectively identified from two maternal-fetal medicine units in Hong Kong from January 2014 to December 2018. Degrees of fetal ventriculomegaly were classified as mild (10-11.9 mm), moderate (12-14.9 mm), or severe (≥15 mm). Genetic investigation results were reviewed, including conventional karyotyping and chromosomal microarray analysis (CMA); correlations between chromosomal abnormalities and the degree of fetal ventriculomegaly were explored. The neurological outcomes of subsequent live births were analysed to identify factors associated with developmental delay.

RESULTS

Of 84 cases (ie, pregnant women and their fetuses) included, 46 (54.8%) exhibited isolated fetal ventriculomegaly, 55 (65.5%) had mild cerebral ventriculomegaly, and 29 (34.5%) had moderate or severe cerebral ventriculomegaly. Overall, 20% (14/70) of cases had chromosomal abnormalities. Moreover, 12% (3/25) of mild isolated ventriculomegaly cases had abnormal karyotype or CMA results. The CMA provided an incremental diagnostic yield of 8.6% (6/70), compared with conventional karyotyping; 4.3% exhibited pathogenic variants and 4.3% exhibited variants of uncertain significance. Among the 53 live births in the cohort, fewer cases of mild isolated ventriculomegaly were associated with developmental delay than more severe isolated ventriculomegaly (9.7% vs 41.7%, P<0.03).

CONCLUSIONS

Chromosomal microarray analysis testing should be offered to all women with fetal cerebral ventriculomegaly, including women with isolated mild ventriculomegaly. The incidence of developmental delay after birth increases with the degree of prenatal cerebral ventriculomegaly.

Effectiveness of a childbirth massage programme for labour pain relief in nulliparous pregnant women at term: a randomised controlled trial

INTRODUCTION

The effect of massage for pain relief during labour has been controversial. This study investigated the efficacy of a programme combining intrapartum massage, controlled breathing, and visualisation for non-pharmacological pain relief during labour.

METHODS

This randomised controlled trial was conducted in two public hospitals in Hong Kong. Participants were healthy low-risk nulliparous Chinese women ≥18 years old whose partners were available to learn massage technique. Recruitment was performed at 32 to 36 weeks of gestation; women were randomised to attend a 2-hour childbirth massage class at 36 weeks of gestation or to receive usual care. The primary outcome variable was the intrapartum use of epidural analgesia or intramuscular pethidine injection.

RESULTS

In total, 233 and 246 women were randomised to the massage and control groups, respectively. The use of epidural analgesia or pethidine did not differ between the massage and control groups (12.0% vs 15.9%; P=0.226). Linear-by-linear analysis demonstrated a trend whereby fewer women used strong pharmacological pain relief in the massage group, and a greater proportion of women had analgesic-free labour (29.2% vs 21.5%; P=0.041). Cervical dilatation at the time of pethidine/epidural analgesia request was significantly greater in the massage group (3.8 ± 1.7 cm vs 2.3 ± 1.0 cm; P<0.001).

CONCLUSION

The use of a massage programme appeared to modulate pain perception in labouring women, such that fewer women requested epidural analgesia and a shift was observed towards the use of weaker pain relief modalities; in particular, more women in the massage group were analgesic-free during labour.

Transperineal ultrasound assessment of fetal head elevation by maneuvers used for managing umbilical cord prolapse

OBJECTIVE

To assess objectively the degree of fetal head elevation achieved by different maneuvers commonly used for managing umbilical cord prolapse.

METHODS

This was a prospective observational study of pregnant women at term before elective Cesarean delivery. A baseline assessment of fetal head station was performed with the woman in the supine position, using transperineal ultrasound for measuring the parasagittal angle of progression (psAOP), head-symphysis distance (HSD) and head-perineum distance (HPD). The ultrasonographic measurements of fetal head station were repeated during different maneuvers, including elevation of the maternal buttocks using a wedge, knee-chest position, Trendelenburg position with a 15° tilt and filling the maternal urinary bladder with 100 mL, 300 mL and 500 mL of normal saline. The measurements obtained during the maneuvers were compared with the baseline measurements.

RESULTS

Twenty pregnant women scheduled for elective Cesarean section at term were included in the study. When compared with baseline (median psAOP, 103.6°), the knee-chest position gave the strongest elevation effect, with the greatest reduction in psAOP (psAOP, 80.7°; P < 0.001), followed by filling the bladder with 500 mL (psAOP, 89.9°; P < 0.001) and 300 mL (psAOP, 94.4°; P < 0.001) of normal saline. Filling the maternal bladder with 100 mL of normal saline (psAOP, 96.1°; P = 0.001), the Trendelenburg position (psAOP, 96.8°; P = 0.014) and elevating the maternal buttocks (psAOP, 98.3°; P = 0.033) gave modest elevation effects. Similar findings were reported for HSD and HPD. The fetal head elevation effects of the knee-chest position, Trendelenburg position and elevation of the maternal buttocks were independent of the initial fetal head station, but that of bladder filling was greater when the initial head station was low.

CONCLUSIONS

To elevate the fetal presenting part, the knee-chest position provides the best effect, followed by filling the maternal urinary bladder with 500 mL then 300 mL of fluid, respectively. Filling the bladder with 100 mL of fluid, the Trendelenburg position and elevation of the maternal buttocks have modest effects. © 2020 International Society of Ultrasound in Obstetrics and Gynecology.

P-064 Application of an artificial intelligence model for morphologic prediction of fertilization-competent human spermatozoa

Study question

What is the role of artificial intelligence in selecting fertilization-competent human spermatozoa according to their morphological characteristics? 

Summary answer

The established AI model in this study can be potentially used to select semen samples with superior fertilization potential in clinical settings.

What is known already

Defective spermatozoa-zona pellucida (ZP) interaction causes subfertility and is a major cause of low IVF fertilization rates. While ICSI benefits patients with defective spermatozoa-ZP binding, a standard method to identify such patients prior to conventional IVF is lacking. The application of artificial intelligence to sperm morphology analysis has become a topic of growing interest owing to the fact that the conventional assessment is highly subjective and time-consuming. Deep-learning, a core element of artificial intelligence (AI), incorporates the convolutional neural networks (CNN) to process all the data composing a digital image through successive layers to identify the underlying pattern.

Study design, size, duration

The fertilization-competent spermatozoa were isolated according to their binding ability to the ZP. The ZP-bound and -unbound spermatozoa were collected for functional assays and to establish an AI model for morphologic prediction of sperm fertilization potential. Human spermatozoa (n = 289) were isolated from normozoospermic samples. Human oocytes (n = 562) were collected from an assisted reproduction program in Hong Kong. Sample collection has been ongoing and will continue until the end of this study in November 2021.

Participants/materials, setting, methods

Sperm-ZP binding assay was employed to collect ZP-bound and -unbound spermatozoa. The fertilization potential and genetic quality of the collected spermatozoa were evaluated by our established protocols. Diff-Quik- stained images of ZP-bound and -unbound spermatozoa were collected respectively for the establishment of an AI model. A novel algorithm for sperm image transformation and segmentation was developed to pre-process the images. CNN architecture was then applied on these pre-processed images for feature extraction and model training.

Main results and the role of chance

Our result showed that the sperm-ZP binding assay had no detrimental effect on sperm viability when compared with the raw samples and unbound-sperm subpopulations. ZP-bound spermatozoa were found with statistically higher acrosome reaction rates, improved DNA integrity, better morphology, lower protamine deficiency and higher methylation level when compared with the unbound spermatozoa. A deep-learning model was trained and validated by analyzing a total of 1,334 and 885 of ZP-bound/unbound spermatozoa to evaluate the predictive power of sperm morphology for ZP binding ability. Our newly trained AI-based model showed initial success in classifying the ZP-bound/ unbound spermatozoa according to their morphological characteristics with high accuracy of 85% and low computational complexity.

Limitations, reasons for caution

This sperm selection method requires micromanipulation and relatively long processing time to recover ZP-bound spermatozoa. In addition to limited availability, the use of human materials may result in interassay variations affecting the reproducibility of this method among laboratories.

Wider implications of the findings

In light of current findings, AI-based sperm selection method may provide high predictive values of sperm fertilization potential for clinical purposes. This method is particularly applicable to patients who had poor fertilization outcomes after conventional IVF treatments or those with high degree of defective sperm-ZP binding ability. 

Trial registration number

not applicable

P–064 Application of an artificial intelligence model for morphologic prediction of fertilization-competent human spermatozoa

Study question

What is the role of artificial intelligence in selecting fertilization-competent human spermatozoa according to their morphological characteristics? Summary answer: The established AI model in this study can be potentially used to select semen samples with superior fertilization potential in clinical settings.

What is known already

Defective spermatozoa-zona pellucida (ZP) interaction causes subfertility and is a major cause of low IVF fertilization rates. While ICSI benefits patients with defective spermatozoa-ZP binding, a standard method to identify such patients prior to conventional IVF is lacking. The application of artificial intelligence to sperm morphology analysis has become a topic of growing interest owing to the fact that the conventional assessment is highly subjective and time-consuming. Deep-learning, a core element of artificial intelligence (AI), incorporates the convolutional neural networks (CNN) to process all the data composing a digital image through successive layers to identify the underlying pattern.

Study design, size, duration

The fertilization-competent spermatozoa were isolated according to their binding ability to the ZP. The ZP-bound and -unbound spermatozoa were collected for functional assays and to establish an AI model for morphologic prediction of sperm fertilization potential. Human spermatozoa (n = 289) were isolated from normozoospermic samples. Human oocytes (n = 562) were collected from an assisted reproduction program in Hong Kong. Sample collection has been ongoing and will continue until the end of this study in November 2021.

Participants/materials, setting, methods

Sperm-ZP binding assay was employed to collect ZP-bound and -unbound spermatozoa. The fertilization potential and genetic quality of the collected spermatozoa were evaluated by our established protocols. Diff-Quik- stained images of ZP-bound and -unbound spermatozoa were collected respectively for the establishment of an AI model. A novel algorithm for sperm image transformation and segmentation was developed to pre-process the images. CNN architecture was then applied on these pre-processed images for feature extraction and model training.

Main results and the role of chance

Our result showed that the sperm-ZP binding assay had no detrimental effect on sperm viability when compared with the raw samples and unbound-sperm subpopulations. ZP-bound spermatozoa were found with statistically higher acrosome reaction rates, improved DNA integrity, better morphology, lower protamine deficiency and higher methylation level when compared with the unbound spermatozoa. A deep-learning model was trained and validated by analyzing a total of 1,334 and 885 of ZP-bound/unbound spermatozoa to evaluate the predictive power of sperm morphology for ZP binding ability. Our newly trained AI-based model showed initial success in classifying the ZP-bound/ unbound spermatozoa according to their morphological characteristics with high accuracy of 85% and low computational complexity.

Limitations, reasons for caution

This sperm selection method requires micromanipulation and relatively long processing time to recover ZP-bound spermatozoa. In addition to limited availability, the use of human materials may result in interassay variations affecting the reproducibility of this method among laboratories.

Wider implications of the findings: In light of current findings, AI-based sperm selection method may provide high predictive values of sperm fertilization potential for clinical purposes. This method is particularly applicable to patients who had poor fertilization outcomes after conventional IVF treatments or those with high degree of defective sperm-ZP binding ability.

Trial registration number

Not applicable

Outcome of radiofrequency ablation for selective fetal reduction before vs at or after 16 gestational weeks in complicated monochorionic pregnancy

OBJECTIVE

To investigate whether gestational age at intervention (< or ≥ 16 weeks) and other factors affect the risk of loss of the cotwin after selective fetal reduction using radiofrequency ablation (RFA) in monochorionic (MC) pregnancy.

METHODS

This was a single-center retrospective analysis of 63 consecutive RFA procedures performed at our institution from January 2011 to October 2019 for selective fetal reduction in complicated MC pregnancies. Indications for RFA were twin reversed arterial perfusion sequence (13 cases), twin-to-twin transfusion syndrome (12 cases), twin anemia-polycythemia sequence (two cases), selective fetal growth restriction (10 cases), discordant anomalies (17 cases) and multifetal pregnancy reduction in triplets or quadruplets with a MC pair (nine cases). Twenty-six (41.3%) of these procedures were performed before and 37 (58.7%) after 16 weeks. Potential factors that could affect the risk of loss of the cotwin, including gestational age at RFA, order of multiple pregnancy, amnionicity, indication for RFA and number of ablation cycles, were assessed first by univariate analysis and then by multivariate analysis.

RESULTS

There were 17 (27.0%) cotwin losses. Ablation cycles numbering four or more was the only factor among those investigated to be associated with loss of the cotwin after RFA (P = 0.035; odds ratio, 5.21), while the indication for RFA, order of multiple pregnancy, amnionicity and gestational age at RFA had no effect. Comparing RFA performed at < 16 vs ≥ 16 weeks, there was no difference in the rate of cotwin loss (23.1% vs 29.7%; P = 0.558) or preterm prelabor rupture of the membranes before 34 weeks (7.7% vs 5.4%; P = 0.853), or in the median gestational age at delivery (36.2 vs 37.3 weeks; P = 0.706).

CONCLUSIONS

RFA is a promising tool for early selective fetal reduction in MC pregnancy before 16 weeks. Four or more ablation cycles is a major risk factor for cotwin loss. Careful assessment pre- and post-RFA, together with proficient operative skills to minimize the number of ablation cycles, are the mainstay to ensure that this procedure is effective and safe. © 2020 International Society of Ultrasound in Obstetrics and Gynecology.

Single-cell RNA sequencing identifies molecular targets associated with poor in vitro maturation performance of oocytes collected from ovarian stimulation

STUDY QUESTION

What is the transcriptome signature associated with poor performance of rescue IVM (rIVM) oocytes and how can we rejuvenate them?

SUMMARY ANSWER

The GATA-1/CREB1/WNT signalling axis was repressed in rIVM oocytes, particularly those of poor quality; restoration of this axis may produce more usable rIVM oocytes.

WHAT IS KNOWN ALREADY

rIVM aims to produce mature oocytes (MII) for IVF through IVM of immature oocytes collected from stimulated ovaries. It is not popular due to limited success rate in infertility treatment. Genetic aberrations, cellular stress and the absence of cumulus cell support in oocytes could account for the failure of rIVM.

STUDY DESIGN, SIZE, DURATION

We applied single-cell RNA sequencing (scRNA-seq) to capture the transcriptomes of human in vivo oocytes (IVO) (n = 10) from 7 donors and rIVM oocytes (n = 10) from 10 donors. The effects of maternal age and ovarian responses on rIVM oocyte transcriptomes were also studied. In parallel, we studied the effect of gallic acid on the maturation rate of mouse oocytes cultured in IVM medium with (n = 84) and without (n = 85) gallic acid.

PARTICIPANTS/MATERIALS, SETTING, METHODS

Human oocytes were collected from donors aged 28-41 years with a body mass index of <30. RNA extraction, cDNA generation, library construction and sequencing were performed in one preparation. scRNA-seq data were then processed and analysed. Selected genes in the rIVM versus IVO comparison were validated by quantitative real-time PCR. For the gallic acid study, we collected immature oocytes from 5-month-old mice and studied the effect of 10-μM gallic acid on their maturation rate.

MAIN RESULTS AND THE ROLE OF CHANCE

The transcriptome profiles of rIVM/IVO oocytes showed distinctive differences. A total of 1559 differentially expressed genes (DEGs, genes with at least 2-fold change and adjusted P < 0.05) were found to be enriched in metabolic processes, biosynthesis and oxidative phosphorylation. Among these DEGs, we identified a repression of WNT/β-catenin signalling in rIVM when compared with IVO oocytes. We found that oestradiol levels exhibited a significant age-independent correlation with the IVO mature oocyte ratio (MII ratio) for each donor. rIVM oocytes from women with a high MII ratio were found to have over-represented cellular processes such as anti-apoptosis. To further identify targets that contribute to the poor clinical outcomes of rIVM, we compared oocytes collected from young donors with a high MII ratio with oocytes from donors of advanced maternal age and lower MII ratio, and revealed that CREB1 is an important regulator. Thus, our study identified that GATA-1/CREB1/WNT signalling was repressed in both rIVM oocytes versus IVO oocytes and in rIVM oocytes of lower versus higher quality. Consequently we investigated gallic acid, as a potential antioxidant substrate in human rIVM medium, and found that it increased the mouse oocyte maturation rate by 31.1%.

LARGE SCALE DATA

Raw data from this study can be accessed through GSE158539.

LIMITATIONS, REASONS FOR CAUTION

In the rIVM oocytes of the high- and low-quality comparison, the number of samples was limited after data filtering with stringent selection criteria. For the oocyte stage identification, we were unable to predict the presence of oocyte spindle, so polar body extrusion was the only indicator.

WIDER IMPLICATIONS OF THE FINDINGS

This study showed that GATA-1/CREB1/WNT signalling was repressed in rIVM oocytes compared with IVO oocytes and was further downregulated in low-quality rIVM oocytes, providing us the foundation of subsequent follow-up research on human oocytes and raising safety concerns about the clinical use of rescued oocytes.

STUDY FUNDING/COMPETING INTEREST(S)

This work was supported by the Collaborative Research Fund, Research Grants Council, C4054-16G, and Research Committee Funding (Research Sustainability of Major RGC Funding Schemes), The Chinese University of Hong Kong. The authors have no conflicts of interest to declare.

Clinical utility of expanded non-invasive prenatal screening and chromosomal microarray analysis in high-risk pregnancy

OBJECTIVE

To evaluate the utility of expanded non-invasive prenatal screening (NIPS), compared with chromosomal microarray analysis (CMA), for the detection of chromosomal abnormalities in high-risk pregnancies.

METHODS

This was a multicenter retrospective study of singleton pregnancies at high risk for chromosomal abnormality. Patients who underwent expanded NIPS and CMA sequentially during pregnancy from 2015 to 2019 were included in the analysis. Pregnancies with a positive result for sex chromosome aneuploidy were excluded as the full details could not be retrieved. The utility of expanded NIPS and CMA for detection of chromosomal abnormalities in this cohort was compared by assessing the concordance between the results.

RESULTS

Of the 774 included high-risk pregnancies, 550 (71.1%) had a positive NIPS result, while a positive CMA result was detected in 308 (39.8%) cases. The rate of full or partial concordance between NIPS and CMA was 82.2%, 59.6% and 25.0% for trisomies 21, 18 and 13, respectively. For rare aneuploidies and segmental imbalances, NIPS and CMA results were fully or partially concordant in 7.5% and 33.3% of cases, respectively. Copy-number variants < 5 Mb were detected more often by CMA, with an incidence of 7.9% (61/774) compared with 3.1% (24/774) by NIPS. A genetic aberration was detected by CMA in 1 in 17 (5.8%) high-risk pregnancies that had a negative or non-reportable NIPS result.

CONCLUSION

CMA allows for comprehensive detection of genome-wide chromosomal abnormalities in high-risk pregnancies. CMA should be offered instead of expanded NIPS for high-risk pregnancies. Copyright © 2020 ISUOG. Published by John Wiley & Sons Ltd.

Expanded carrier screening using next-generation sequencing of 123 Hong Kong Chinese families: a pilot study

INTRODUCTION

To determine the carrier frequency and common mutations of Mendelian variants in Chinese couples using next-generation sequencing (NGS).

METHODS

Preconception expanded carrier testing using NGS was offered to women who attended the subfertility clinic. The test was then offered to the partners of women who had positive screening results. Carrier frequency was calculated, and the results of the NGS panel were compared with those of a target panel.

RESULTS

One hundred twenty-three women and 20 of their partners were screened. Overall, 84 (58.7%) individuals were identified to be carriers of at least one disease, and 68 (47.6%) were carriers after excluding thalassaemias. The most common diseases found were GJB2-related DFNB1 nonsyndromic hearing loss and deafness (1 in 4), alpha-thalassaemia (1 in 7), beta-thalassaemia (1 in 14), 21-hydroxylase deficient congenital adrenal hyperplasia (1 in 13), Pendred's syndrome (1 in 36), Krabbe's disease (1 in 48), and spinal muscular atrophy (1 in 48). Of the 43 identified variants, 29 (67.4%) were not included in the American College of Medical Genetics and Genomics or American College of Obstetrics and Gynecology guidelines. Excluding three couples with alpha-thalassaemia, six at-risk couples were identified.

CONCLUSION

The carrier frequency of the investigated members of the Chinese population was 58.7% overall and 47.6% after excluding thalassaemias. This frequency is higher than previously reported. Expanded carrier screening using NGS should be provided to Chinese people to improve the detection rate of carrier status and allow optimal pregnancy planning.

First-trimester pre-eclampsia biomarker profiles in Asian population: multicenter cohort study

OBJECTIVES

To (i) evaluate the applicability of the European-derived biomarker multiples of the median (MoM) formulae for risk assessment of preterm pre-eclampsia (PE) in seven Asian populations, spanning the east, southeast and south regions of the continent, (ii) perform quality-assurance (QA) assessment of the biomarker measurements and (iii) establish criteria for prospective ongoing QA assessment of biomarker measurements.

METHODS

This was a prospective, non-intervention, multicenter study in 4023 singleton pregnancies, at 11 to 13 + 6 weeks' gestation, in 11 recruiting centers in China, Hong Kong, India, Japan, Singapore, Taiwan and Thailand. Women were screened for preterm PE between December 2016 and June 2018 and gave written informed consent to participate in the study. Maternal and pregnancy characteristics were recorded and mean arterial pressure (MAP), mean uterine artery pulsatility index (UtA-PI) and maternal serum placental growth factor (PlGF) were measured in accordance with The Fetal Medicine Foundation (FMF) standardized measurement protocols. MAP, UtA-PI and PlGF were transformed into MoMs using the published FMF formulae, derived from a largely Caucasian population in Europe, which adjust for gestational age and covariates that affect directly the biomarker levels. Variations in biomarker MoM values and their dispersion (SD) and cumulative sum tests over time were evaluated in order to identify systematic deviations in biomarker measurements from the expected distributions.

RESULTS

In the total screened population, the median (95% CI) MoM values of MAP, UtA-PI and PlGF were 0.961 (0.956-0.965), 1.018 (0.996-1.030) and 0.891 (0.861-0.909), respectively. Women in this largely Asian cohort had approximately 4% and 11% lower MAP and PlGF MoM levels, respectively, compared with those expected from normal median formulae, based on a largely Caucasian population, whilst UtA-PI MoM values were similar. UtA-PI and PlGF MoMs were beyond the 0.4 to 2.5 MoM range (truncation limits) in 16 (0.4%) and 256 (6.4%) pregnancies, respectively. QA assessment tools indicated that women in all centers had consistently lower MAP MoM values than expected, but were within 10% of the expected value. UtA-PI MoM values were within 10% of the expected value at all sites except one. Most PlGF MoM values were systematically 10% lower than the expected value, except for those derived from a South Asian population, which were 37% higher.

CONCLUSIONS

Owing to the anthropometric differences in Asian compared with Caucasian women, significant differences in biomarker MoM values for PE screening, particularly MAP and PlGF MoMs, were noted in Asian populations compared with the expected values based on European-derived formulae. If reliable and consistent patient-specific risks for preterm PE are to be reported, adjustment for additional factors or development of Asian-specific formulae for the calculation of biomarker MoMs is required. We have also demonstrated the importance and need for regular quality assessment of biomarker values. Copyright © 2019 ISUOG. Published by John Wiley & Sons Ltd.

Transvaginal three-dimensional ultrasound assessment of Sylvian fissures at 18-30 weeks' gestation

OBJECTIVE

To (1) evaluate the normal development of the Sylvian fissures in the anterior coronal view of the fetal brain at 18-30 weeks' gestation by transvaginal three-dimensional (3D) ultrasound, (2) develop reference ranges of measurements of the right and left Sylvian fissure angles during normal pregnancy at 18-30 weeks' gestation, and (3) examine intra- and interobserver repeatability of measurements of the right and left Sylvian fissure angles.

METHODS

This was a prospective cross-sectional study of 422 women with a singleton pregnancy attending an ultrasound-based research clinic between March and December 2017. The entry criteria for the study were appropriately grown live fetus with no suspected structural and/or chromosomal defects between 18 + 0 and 30 + 6 weeks' gestation. Normal development of the Sylvian fissures was assessed in the anterior coronal plane of the fetal brain using transvaginal 3D volume multiplanar imaging. The coronal view was visualized as a single image from the three orthogonal views. Subsequently, the right and left Sylvian fissure angles were measured between a horizontal reference line (0°) and a line drawn along the upper side of the respective Sylvian fissure. Intra- and interobserver repeatability of the Sylvian fissure angle measurements was assessed by Bland-Altman plots. Reference equations were constructed for right and left Sylvian fissure angles for gestational age (GA) and head circumference (HC) using the Generalized Additive Models for Location Scale and Shape package.

RESULTS

In the anterior coronal view of the fetal brain, an inward rotation of the upper portion of the Sylvian fissures was observed during the second and third trimesters of pregnancy. There was a significant negative polynomial association between the Sylvian fissure angles and GA and HC. Both Sylvian fissure angles crossed the reference line (zero), going from positive to negative, at around 25 weeks' gestation or at HC of 22 cm. Z-score difference between the smoothed percentiles of the right and left Sylvian fissure angles indicated that median, 10^th and 90^th smoothed percentiles were closest and almost the same for the GA-based references between 18 and 28 weeks and for the HC-based references between 14 and 24 cm. The intraclass correlation coefficient of the right and left Sylvian fissure angle measurements between the two sonographers was excellent at 0.993 (95% CI, 0.988-0.996) and 0.991 (95% CI, 0.985-0.995), respectively. On Bland-Altman analysis, the mean difference between the two sonographers in right Sylvian fissure angle measurement was 0.4° (95% CI, -10.2 to 10.1°) and in left Sylvian fissure angle it was 1.0° (95% CI, -9.6 to 11.6°).

CONCLUSIONS

Assessment of the Sylvian fissure angles is highly reproducible. Sylvian fissure angle reference charts can serve as a screening tool for malformations of cortical development, guiding subsequent follow-up and referral for fetal brain magnetic resonance imaging and/or assessment by an expert neurosonologist. Copyright © 2018 ISUOG. Published by John Wiley & Sons Ltd.

Parental consanguinity in Hong Kong

INTRODUCTION

Consanguineous union increases the risk of genetic disorders in offspring. The present study aimed to evaluate the prevalence and characteristics of parental consanguinity in Hong Kong, and its effects on pregnancy, perinatal, and child health outcomes.

METHODS

Pregnant women in consanguineous unions attending an obstetrics unit at a public hospital in Hong Kong were retrospectively studied. Their pregnancy, perinatal, and child health outcomes were compared with an ethnicity-matched control group of pregnant women in non-consanguineous unions.

RESULTS

The overall prevalence of parental consanguinity was 0.6% (first cousins or closer, 78.4%; beyond first cousins, 21.6%). The majority were ethnic Pakistani (85.0%). Women in consanguineous unions were more likely to have an obstetric history of congenital abnormality (10.5%), unexplained intrauterine fetal demise (4.2%) and unexplained neonatal death (4.6%), or family history of congenital abnormality (4.6%). Offspring of consanguineous parents had significantly higher risk of recessive diseases (odds ratio [OR]=8.70, 95% confidence interval [CI]=1.06-71.36), structural abnormalities (OR=4.55, 95% CI=2.17-9.53) and developmental delay (OR=6.72, 95% CI=1.48-30.63), and significantly higher incidence of autistic spectrum disorder (2.1%; P=0.008).

CONCLUSIONS

It is essential that information on the increased risks associated with parental consanguinity is included in genetic counselling for consanguineous couples, so that they can make informed decisions.

Prevalence of chromosomal abnormalities and 22q11.2 deletion in conotruncal and non-conotruncal antenatally diagnosed congenital heart diseases in a Chinese population

INTRODUCTION

The aim of the present study was to calculate the prevalence of chromosomal abnormalities among antenatally diagnosed congenital heart diseases (CHDs), and the prevalence of 22q11.2 deletion in those with conotruncal CHDs versus isolated non-conotruncal CHDs.

METHODS

All patients with antenatal ultrasound finding of fetal CHDs in two obstetric units in a 5-year period were retrospectively reviewed. Detected CHDs were classified as conotruncal if the malformation involved either the aortic outflow tract or the pulmonary outflow tract; otherwise they were classified as non-conotruncal. Karyotyping, fluorescence in situ hybridisation for 22q11.2 deletion (22q11FISH), and array comparative genomic hybridisation (aCGH) results were retrieved from patient medical records. The primary outcome was prevalence of chromosomal abnormalities in CHDs. The secondary outcomes were prevalence of 22q11.2 deletion and its prevalence in conotruncal versus non-conotruncal CHDs.

RESULTS

A total of 254 Chinese patients were diagnosed to have fetal CHDs. In all, 50 (19.7%) were found to have chromosomal abnormalities with seven (2.8%) patients having 22q11.2 deletion, of whom all seven had conotruncal CHDs and none had non-conotruncal CHDs (P<0.05). Conventional karyotyping detected 35 (70%) cases of the chromosomal abnormalities. The 22q11FISH detected three cases of 22q11.2 deletion; aCGH was performed to detect four cases of 22q11.2 deletion and eight other cases of copy number variations.

CONCLUSION

Our results suggest that invasive testing for karyotyping is recommended for fetal CHDs. Although the prevalence of 22q11.2 deletion was low, testing for 22q11.2 deletion should be offered for conotruncal CHDs.

Transverse technique: complementary approach to measurement of first-trimester uterine artery Doppler

OBJECTIVES

To define a protocol for the first-trimester assessment of uterine artery pulsatility index (UtA-PI) using the new transverse technique, to evaluate UtA-PI measured using the transverse approach vs that obtained using the conventional sagittal approach and to determine if accelerated onsite training (in both methods) of inexperienced sonographers can achieve reproducible UtA-PI measurements comparable with those obtained by an experienced sonographer.

METHODS

This was a prospective observational study of women with a singleton pregnancy attending for routine combined first-trimester screening at 11 to 13 + 6 weeks' gestation. The study consisted of two parts, each conducted at a different center (Part 1 in Calgary, Canada and Part 2 in Hong Kong). In Part 1, UtA-PI measurements were performed using the transverse and sagittal techniques by four sonographers trained in both methods, in 10 cases each, and measurement indices (PI), time required and subjective difficulty in obtaining satisfactory measurements were compared. The one sample t-test and Wilcoxon signed rank test were used when appropriate. Bland-Altman plots were used to assess measurement agreement, and intraclass correlation coefficient (ICC) was used to evaluate measurement reliability. A target plot was used to assess measures of central tendency and dispersion. In Part 2, one experienced and three inexperienced sonographers prospectively measured UtA-PI using both approaches in 42 and 35 women, respectively. Inexperienced sonographers underwent accelerated onsite training by the experienced sonographer. Measurement approach and sonographer order were on a random basis. ICC, Bland-Altman and Passing-Bablok analyses were performed to assess measurement agreement and reliability and effect of accelerated training.

RESULTS

In Part 1, no difference was observed between the two techniques in mean time to acquire the measurements (118 s for sagittal vs 106 s for transverse; P = 0.38). The four sonographers reported that the transverse technique was subjectively easier to perform (P = 0.04). Bias and ICC for mean UtA-PI between sagittal and transverse measurements were -0.05 (95% limits of agreement, -0.48 to 0.37) and 0.94, respectively. Measurements obtained using the transverse technique after correcting for gestational age were significantly closer to the expected distribution than those obtained using the sagittal technique. In Part 2, there were no significant differences in median UtA-PI measured using the different approaches for both experienced and inexperienced sonographers (P > 0.05 for all sonographers). Mean UtA-PI measurement reliability between approaches was high for the experienced (ICC = 0.92) and inexperienced (ICC > 0.80) sonographers. UtA-PI measurement approaches did not deviate from linearity, while bias ranged from -0.10 to 0.07. The median time required was similar between the techniques (56.1 s for sagittal vs 49.3 s for transverse; P = 0.054).

CONCLUSIONS

This novel transverse approach for the measurement of UtA-PI in the first trimester appears to be comparable with the sagittal approach in terms of reliability, reproducibility and time required, and may be easier to perform. Providing accelerated onsite training can be helpful for improving the reliability of UtA-PI measurements and could potentially facilitate the broad implementation of first-trimester pre-eclampsia screening. Copyright © 2017 ISUOG. Published by John Wiley & Sons Ltd.

Impact of replacing Chinese ethnicity-specific fetal biometry charts with the INTERGROWTH-21(st) standard

OBJECTIVE

To assess the impact of adopting the INTERGROWTH-21(st) biometry standards in a Chinese population.

DESIGN

Retrospective cohort study.

SETTING

A teaching hospital in Hong Kong.

POPULATION

A total of 10 527 Chinese women with a singleton pregnancy having a second- or third-trimester fetal anomaly or growth scan between January 2009 and June 2014.

METHODS

Z-scores were derived for fetal abdominal circumference (AC), head circumference (HC), and femur length (FL) using the INTERGROWTH-21(st) and Chinese biometry standards. Pregnancies with aneuploidy, structural or skeletal abnormalities, or that developed pre-eclampsia were excluded. Z-scores were stratified as <2.5th, <5th, <10th, >90th, >95th, or >97.5th percentile. Birthweight centile, adjusted for gestation and gender, was categorised as ≤3rd, 3rd to ≤5th, 5th to ≤10th, and >10th. Pairwise comparison and the McNemar test were performed to assess biometry Z-score differences and concordance between the INTERGROWTH-21(st) and Chinese standards.

MAIN OUTCOME MEASURES

The sensitivity of both the local and INTERGROWTH-21(st) AC standards to identify pregnancies that were small-for-gestational-age (SGA) was assessed.

RESULTS

INTERGROWTH-21(st) AC, HC, and FL Z-scores were significantly lower than those obtained using our local reference for AC, HC, and FL (P < 0.0001 for all). The proportion of fetuses with biometry in the <2.5th, <5th, <10th, >90th, >95th, or >97.5th percentiles was statistically significant (P < 0.01 for all). A total of 1224 (15.5%) of the scans at 18-22 weeks of gestation had AC, HC, or FL below the 3rd percentile of the INTERGROWTH-21(st) standard.

CONCLUSIONS

Adopting the INTERGROWTH-21(st) standard would lead to a significant number of fetuses being at risk of misdiagnosis for small fetal size, particularly when using HC and FL measures.

TWEETABLE ABSTRACT

INTERGROWTH-21(st) biometry assessment in Chinese leads to fetuses being at risk of misdiagnosis of small fetal size.

Prospective assessment of INTERGROWTH-21st and World Health Organization estimated fetal weight reference curves

OBJECTIVES

To assess the suitability of the new INTERGROWTH-21^st and World Health Organization (WHO) estimated fetal weight (EFW) references in a Southern Chinese population. A secondary aim was to determine the accuracy of EFW by assessing the difference between EFW and actual birth weight.

METHODS

This was a prospective cross-sectional cohort study. Viable singleton pregnancies at 11-13 weeks' gestation were recruited to undergo a single standardized fetal biometric scan after 20 weeks. The gestational age at which the scan was performed was allocated randomly at the time of recruitment. EFW was predicted using both the Hadlock and INTERGROWTH-21^st weight estimation model formulae. Population-specific EFW references were constructed. Z-scores were used to compare these references against the INTERGROWTH-21^st and WHO international size references. Gestational-age-adjusted projection was used to assess the difference between EFW on the day of delivery and birth weight for fetuses having biometry scans ≥ 34 weeks.

RESULTS

Fetuses of 970 participants had biometry scans. The median number of scans per gestational week was 48 (interquartile range, 43-53). Z-score comparison indicated that the WHO 10^th , 50^th and 90^th centiles of the EFW reference were consistently higher than the corresponding local centiles, whilst the INTERGROWTH-21^st 10^th centile was lower. Fewer than 2% of fetuses scanned at or after 34 weeks would be considered as potentially large-for-gestational age, irrespective of which model was used to predict weight. Adopting the WHO international reference would result in approximately one in six fetuses being regarded as potentially small-for-gestational age, 50% more than the number determined using a population-specific reference. Systematic errors of extrapolated EFW were similar, ranging from 5.5% to 7.4%.

CONCLUSIONS

Centers seeking to use new references, such as the INTERGROWTH-21^st and/or WHO international references, as a means of determining whether a fetus is small- or large-for-gestational age, would be advised to assess the suitability of these references within their own population using standardized methodology. Copyright © 2017 ISUOG. Published by John Wiley & Sons Ltd.

First trimester screening for pre-eclampsia in Chinese pregnancies: case-control study

OBJECTIVE

To assess the potential of screening for pre-eclampsia (PE) in a Chinese population.

DESIGN

Case-control study.

SETTING

Teaching hospital in Hong Kong.

POPULATION

A total of 3330 women having a viable singleton pregnancy attending first-trimester Down-syndrome screening.

METHODS

Mean arterial pressure (MAP), bilateral uterine artery pulsatility index (UtA-PI), and placental growth factor (PlGF) were measured. Screening markers were transformed to multiples of the gestational median (MoM) and adjusted for maternal and pregnancy characteristics. MoM distributions in PE and non-PE pregnancies were compared with published expected values. PE screening performance was assessed using area under receiver operating curves (AUROC).

MAIN OUTCOME MEASURES

PE detection rate.

RESULTS

A total of 30 (0.9%) women developed either early (<34 weeks) or late (≥34 weeks) onset PE. MAP was dependent on maternal BMI, UtA-PI on fetal crown rump length, uterine artery peak systolic velocity (UtA-PSV) on maternal age and gestation, and PlGF on gestation in non-PE pregnancies. MoM distributions determined using published Fetal Medicine Foundation models deviated significantly from one for both MAP (P < 0.0001) and PI (P < 0.0001), but not PlGF (P = 0.52) in non-PE pregnancies, whilst PlGF MoM distributions in those who developed early as opposed to late onset PE were significantly higher (P = <0.05). AUROC for any PE using multiple markers was 0.72 (95% CI: 0.64-0.81) with detection rates of 72 and 55% for early and late PE, respectively, for a 10% false positive rate.

CONCLUSION

Detection rates for PE in our Chinese population were lower than the expected 90-95% even after adjusting MoM for local women's characteristics.

FUNDING

General Research Fund (Project number 470513).

TWEETABLE ABSTRACT

Pre-eclampsia screening in the Chinese population had detection rates lower than previously published results.

Expanded newborn metabolic screening programme in Hong Kong: a three-year journey

INTRODUCTION

No universal expanded newborn screening service for inborn errors of metabolism is available in Hong Kong despite its long history in developed western countries and rapid development in neighbouring Asian countries. To increase the local awareness and preparedness, the Centre of Inborn Errors of Metabolism of the Chinese University of Hong Kong started a private inborn errors of metabolism screening programme in July 2013. This study aimed to describe the results and implementation of this screening programme.

METHODS

We retrieved the demographics of the screened newborns and the screening results from July 2013 to July 2016. These data were used to calculate quality metrics such as call-back rate and false-positive rate. Clinical details of true-positive and false-negative cases and their outcomes were described. Finally, the call-back logistics for newborns with positive screening results were reviewed.

RESULTS

During the study period, 30 448 newborns referred from 13 private and public units were screened. Of the samples, 98.3% were collected within 7 days of life. The overall call-back rate was 0.128% (39/30 448) and the false-positive rate was 0.105% (32/30 448). Six neonates were confirmed to have inborn errors of metabolism, including two cases of medium-chain acyl-coenzyme A dehydrogenase deficiency, one case of carnitine-acylcarnitine translocase deficiency, and three milder conditions. One case of maternal carnitine uptake defect was diagnosed. All patients remained asymptomatic at their last follow-up.

CONCLUSION

The Centre of Inborn Errors of Metabolism has established a comprehensive expanded newborn screening programme for selected inborn errors of metabolism. It sets a standard against which the performance of other private newborn screening tests can be compared. Our experience can also serve as a reference for policymakers when they contemplate establishing a government-funded universal expanded newborn screening programme in the future.

Triplet pregnancy with fetal reduction: experience in Hong Kong

INTRODUCTION

Triplet and higher-order multiple pregnancies are well known to be associated with increased adverse outcomes. This study reviewed the perinatal outcomes in women with a triplet pregnancy who underwent fetal reduction versus expectant management at a university hospital in Hong Kong.

METHODS

This was a retrospective review of triplet pregnancies at Prince of Wales Hospital in Hong Kong from 1 January 2008 to 30 September 2014. Women carrying a triplet pregnancy were classified as having had expectant management, fetal reduction to twins, or fetal reduction to a singleton. Maternal and pregnancy characteristics were compared. Outcome measures included fetal loss, gestational age at delivery, birth weight, neonatal survival rate, neonatal death, neonatal complications, and need for and length of neonatal intensive care unit stay.

RESULTS

A total of 52 triplet pregnancies were identified. One pregnancy that was lost to follow-up and one that was terminated were excluded. The majority of pregnancies (84%) were the result of assisted reproductive technology. Fetal reduction was performed in 26 (52%) pregnancies, of which 22 were reduced to twins and four to a singleton. The mean gestations at delivery were 32.6, 35.2, and 39.6 weeks in the expectant management, fetal reduction to twins, and fetal reduction to a singleton groups, respectively. Significantly more pregnancies with expectant management resulted in a preterm birth. All pregnancies with fetal reduction to a singleton resulted in a term birth. A higher mean birth weight, lower neonatal death rate, and reduced need for admission to and length of stay in the neonatal intensive care unit were observed in the fetal reduction groups.

CONCLUSIONS

Approximately 50% of women with a triplet pregnancy in Hong Kong elected to undergo fetal reduction. This was associated with a significant reduction in extreme preterm delivery and associated morbidity and mortality.

Antenatal diagnosis and management of foetal intestinal volvulus

In-utero intestinal volvulus is a rare but potential life threatening foetal complications. It is a surgical emergency and delay in diagnosis or treatment can increase the morbidity and mortality to the foetus. We report a case of mild foetal bowel dilatation diagnosed at 21 weeks of gestation. She was closely follow up and at 31 weeks of gestation, in-utero intestinal volvulus was diagnosed with the characteristic 'whirlpool' sign on ultrasound examination. This case emphasises the importance of early recognition and quick decision to delivery when intestinal volvulus is diagnosed. This enabled early surgical intervention to prevent further foetal morbidity.

Identification of fragile X pre-mutation carriers in the Chinese obstetric population using a robust FMR1 polymerase chain reaction assay: implications for screening and prenatal diagnosis

INTRODUCTION

There is significant morbidity associated with fragile X syndrome. Unfortunately, most maternal carriers are clinically silent during their reproductive years. Because of this, many experts have put forward the notion of preconception or prenatal fragile X carrier screening for females. This study aimed to determine the prevalence of fragile X syndrome pre-mutation and asymptomatic full-mutation carriers in a Chinese pregnant population, and the distribution of cytosine-guanine-guanine (CGG) repeat numbers using a robust fragile X mental retardation 1 (FMR1) polymerase chain reaction assay.

METHODS

This was a cross-sectional survey in prospectively recruited pregnant women from a university hospital in Hong Kong. Chinese pregnant women without a family history of fragile X syndrome were recruited between April 2013 and May 2015. A specific FMR1 polymerase chain reaction assay was performed on peripheral blood to determine the CGG repeat number of the FMR1 gene. Prenatal counselling was offered to full-mutation and pre-mutation carriers.

RESULTS

In 2650 Chinese pregnant women, two individuals with pre-mutation alleles (0.08%, one in 1325) and one asymptomatic woman with full-mutation (0.04%, one in 2650) alleles were identified. The overall prevalence of pre-mutation and full-mutation alleles was 0.11% (1 in 883). Furthermore, 30 (1.1%) individuals with intermediate alleles were detected. In the 2617 women with normal CGG repeats, the most common CGG repeat allele was 30.

CONCLUSIONS

The overall prevalence of pre-mutation and asymptomatic full-mutation carriers in the Chinese pregnant population was one in 883, detected by a new FMR1 polymerase chain reaction assay.

The pattern of cervical smear abnormalities in marginalised women in Hong Kong

INTRODUCTION

"Ripple Action" and "WE Stand" are projects co-organised by the Hong Kong Women Doctors Association. The two projects organise free cervical screening for low-income women, new immigrants from Mainland China, and ethnic minority women. The objective of this study was to analyse the pattern of cervical smear abnormalities in these marginalised women.

METHODS

The study group consisted of 1189 marginalised women who participated in a free cervical screening campaign, including 324 low-income local Chinese, 540 new immigrants from Mainland China, and 325 ethnic minority women. The comparison group consisted of 1141 local Chinese who attended a well women clinic. The prevalence of cervical smear abnormalities was compared using Chi squared test.

RESULTS

In the study group, 42.6% of women had never had a cervical smear. Compared with the comparison group, they had a significantly higher prevalence of cervical smear abnormalities (13.7% vs 1.4%; P<0.001), including atypical smear (10.8% vs 0.5%; P<0.001), low-grade lesion (1.8% vs 0.8%; P=0.036), and high-grade lesion (1.1% vs 0.1%; P=0.002). Logistic regression analysis showed that the strongest predictors for abnormal cervical smear were being South Asian (odds ratio=11.859; 95% confidence interval, 4.635-30.341), South-East Asian (6.484; 3.192-13.171), or new immigrant from Mainland China (6.253; 2.463-15.877).

CONCLUSIONS

Marginalised women had a significantly higher prevalence of cervical smear abnormality than the general population and almost half had never had a cervical smear before. Outreach strategies are needed to enrol this population into screening programmes.