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.

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.

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

OBJECTIVES: To assess the suitability of the new INTERGROWTH-21st 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-21st weight estimation model formulae. Population-specific EFW references were constructed. Z-scores were used to compare these references against the INTERGROWTH-21st 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 10th , 50th and 90th centiles of the EFW reference were consistently higher than the corresponding local centiles, whilst the INTERGROWTH-21st 10th 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-21st 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.

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.

Diagnostic accuracy of the BACs-on-Beads™ assay versus karyotyping for prenatal detection of chromosomal abnormalities: a retrospective consecutive case series.

OBJECTIVE: To evaluate the diagnostic performance of the BACs-on-Beads(™) (BoBs(™)) assay for prenatal detection of chromosomal abnormalities. DESIGN: Retrospective study. SETTING: Tertiary prenatal diagnosis centre. POPULATION: Women referred for prenatal diagnosis. METHODS: We retrieved 2153 archived DNA samples collected between January 2010 and August 2011 for the BoBs(™) assay. These samples had previously been tested by quantitative fluorescence polymerase chain reaction (QF-PCR) and karyotyping. In the BoBs(™) assay a sample was defined as normal disomic when the ratio of the fluorescence intensities in a chromosome locus lay within the threshold (mean ratio ± 2SD), and as deleted or duplicated when the ratio was below the lower threshold (0.6-0.8) or above the upper threshold (1.3-1.4), respectively. The BoBs(™) results were further validated by microarray and compared in a blinded manner with the original QF-PCR and karyotyping results. MAIN OUTCOME MEASURES: Concordance of any numerical, structural, and submicroscopic chromosomal abnormalities between the methods. RESULTS: BACs-on-Beads(™) was similar to karyotyping and QF-PCR in detecting trisomy 13, trisomy 18, trisomy 21, and sex chromosomal aneuploidies, and superior to QF-PCR in detecting major structural abnormalities (53.3 versus 13.3%) and mosaicism (28.6 versus 0%) involving chromosomal abnormalities other than the common aneuploidies. BoBs(™) detected six microdeletion syndromes missed by karyotyping and QF-PCR; however, BoBs(™) missed two cases of triploidy identified by QF-PCR. Therefore, the sensitivity of BoBs(™) is 96.7% (95% CI 92.6-98.7%), and its specificity is 100% (95% CI 99.8-100%). CONCLUSIONS: BACs-on-Beads(™) can replace QF-PCR for triaging in prenatal diagnosis, and gives a better diagnostic yield than current rapid aneuploidy tests.

Maternal ABO and rhesus blood group phenotypes and hepatitis B surface antigen carriage.

In view of a persistently high prevalence of hepatitis B surface antigen (HBsAg) carriage in our obstetric population, we examined the association between HBsAg carriage with maternal ABO and rhesus (Rh) blood group phenotypes determined at routine antenatal screening. In a retrospective study, the antenatal screening results of women booked for confinement between 1998 and 2011 in our hospital were examined for the relationship between HBsAg carriage with the ABO and rhesus blood groups, taking into account also the effects of advanced maternal age (≥ 35 years) and parity status (nulliparous or multiparous), and year of birth before or following the availability of the hepatitis B vaccine (1984). HBsAg carriage was found in 9.9%, 9.6%, 9.1% and 10.2% (P = 0.037) for group-A (n = 20 581 or 26.1%), -B (n = 20 744 or 26.4%), -AB (n = 5138 or 6.5%) and -O (n = 32 242 or 41.0%) among the 78705 women in the study cohort. Rhesus negativity was found in 0.6%, and HBsAg carriage was 12.3% and 9.8%, respectively, for the Rh-negative and Rh-positive women (P = 0.071). Carriage rate between group-O and non-O was influenced by nulliparity, age ≥ 35 years and Rh-positive status. Regression analysis indicated that group-B (P = 0.044, aOR = 1.062, 95% CI 1.002-1.127) and group-AB (P = 0.016, aOR = 1.134, 95% CI 1.024-1.256) were associated with HBsAg carriage. Blood groups-B and -AB are associated with increased hepatitis B virus (HBV) infection in our population, and further studies are warranted to elucidate the implications of this on the sequelae of HBV infection.

Maternal hepatitis B surface antigen status and incidence of pre-eclampsia.

The relationship between chronic hepatitis B virus (HBV) infection with atherosclerosis and cardiovascular disorders remains unclear, and the impact of maternal HBV infection on the development of pregnancy-induced hypertension (PIH) and pre-eclampsia (PE) is also controversial. This retrospective cohort study was conducted to examine the relationship between maternal hepatitis B surface antigen (HBsAg) status with PIH and PE in singleton pregnancies that delivered at 24 weeks of gestation and beyond. Among the 86 537 cases in the cohort, 10% were HBsAg positive, and overall 2.0% had PIH, of whom 56.3% developed PE. HBsAg-positive women had higher weight and body mass index (BMI), but lower incidences of advanced age, nulliparity, PIH (1.6% vs 2.0%, P = 0.007) and PE (0.8% vs 1.1%, P = 0.005). On multiple logistic regression analysis adjusting for the effects of nulliparity, advanced age, high BMI, and underlying renal, cardiac and autoimmune diseases, HBsAg carriage was associated with significantly reduced incidence of PIH (aOR 0.79, 95% CI 0.66-0.95) and PE (aOR 0.71, 95% CI 0.56-0.91). Our results indicate that maternal HBsAg carriage is independently associated with reduced PE. As chronic HBV infection alters the immune response of the individual, our observation could be related to enhanced maternal immunotolerance of the foetus and hence a reduction in the incidence of PE. The implications of our findings on the long-term health outcome of the infected women, from cardiovascular morbidity to malignancies, warrant further studies.