Pessary for prevention of preterm birth in twin pregnancy with short cervix: 3-year follow-up study.

OBJECTIVE: A recent randomized clinical trial (ProTWIN) showed that a cervical pessary prevented preterm birth and improved neonatal outcome in women with multiple pregnancy and cervical length (CL) < 38 mm. In this follow-up study, the long-term developmental outcome of these children was evaluated at 3 years' corrected age. METHODS: This was a follow-up study of ProTWIN, a multicenter trial conducted between 2009 and 2012 in which asymptomatic women with a multiple pregnancy were randomized to placement of a cervical pessary or no intervention. Current follow-up and analysis were limited to mothers with a mid-trimester CL < 38 mm (78 women (157 children) in the pessary group and 55 women (111 children) in the control group). At 3 years of corrected age, surviving children were invited for a Bayley Scales of Infant and Toddler Development-third edition (Bayley-III) assessment. Death after randomization or neurodevelopmental disability (Bayley-III score of ≤ 85, 1 SD below mean) rates were compared between the pessary and control groups, according to the intention-to-treat principle and using multiple imputation for missing data. Mean Bayley-III scores in surviving children were also assessed. A linear mixed-effects model was used to adjust for correlation between children of one mother. RESULTS: From the time of entry in the ProTWIN trial until follow-up at 3 years of age, a total of 27 children had died (six (5%) in the pessary vs 21 (26%) in the control group; odds ratio (OR), 0.13; 95% CI, 0.04-0.48). Bayley-III outcomes were collected for 173/241 (72%) surviving children (114 (75%) in the pessary vs 59 (66%) in the control group). The cumulative incidence of death or survival with a neurodevelopmental disability was 12 (10%) in the pessary vs 23 (29%) in the control group (OR, 0.26; 95% CI, 0.09-0.73). No statistical or clinically relevant differences were found with respect to cognitive, language and motor development among surviving children between the groups. Comparable results were found after multiple imputation. CONCLUSION: In women with twin pregnancy and a CL < 38 mm, the use of a cervical pessary strongly improved survival of the children without affecting neurodevelopment at 3 years' corrected age. Copyright © 2018 ISUOG. Published by John Wiley & Sons Ltd.

Incidence of and risk indicators for vasa praevia: a systematic review.

BACKGROUND: Vasa praevia (VP) is a rare phenomenon that is assumed to increase the risk of severe complications, including fetal death. Critical data on its incidence are lacking, so there is no rational basis for prenatal screening. OBJECTIVES: To review the literature on the incidence and risk indicators for VP. SEARCH STRATEGY: We searched OVID MEDLINE, OVID EMBASE, the Cochrane Library and PubMed for case-control and cohort studies on incidence and risk indicators for VP. SELECTION CRITERIA: Two reviewers selected studies and scored their methodological quality. DATA COLLECTION AND ANALYSIS: We calculated the mean incidence of VP. We constructed 2 × 2 tables cross-classifying potential risk indicators against the incidence of VP to calculate common odds ratios and 95% confidence intervals, using the Mantel-Haenszel method. MAIN RESULTS: We included 13 studies (two prospective cohort studies, ten retrospective cohort studies and one case-control study) reporting on 569 410 patients with 325 cases of VP. Based on ten included cohort studies providing information on the incidence, the mean incidence of VP was 0.60 per 1000 pregnancies. We identified five different risk indicators and markers for VP: second-trimester placenta praevia, conception by assisted reproductive technologies, a bilobed or succenturiate placenta, umbilical cord insertion in the lower third part of the uterus at first-trimester ultrasound and velamentous cord insertion. Almost 83% of the cases of VP had one or more risk indicators. AUTHORS' CONCLUSIONS: In view of the low incidence, screening for VP in an unselected population is not advised. Targeted screening of women with one or more risk indicators as a part of routine mid-gestation scanning should be considered. TWEETABLE ABSTRACT: Vasa praevia is more common in placenta praevia, conception by ART, velamentous cord insertion and bilobed placenta.

Systematic review of accuracy of ultrasound in the diagnosis of vasa previa.

OBJECTIVE: Vasa previa is an obstetric complication in which the fetal blood vessels lie outside the chorionic plate in close proximity to the internal cervical os. In women with vasa previa, the risk of rupture of these vessels is increased, thus potentially causing fetal death or serious morbidity. Our objective was to assess the accuracy of ultrasound in the prenatal diagnosis of vasa previa. METHODS: We searched MEDLINE, EMBASE, the Cochrane Library and PubMed for studies on vasa previa. Two reviewers independently selected studies on the accuracy of ultrasound in the diagnosis of vasa previa. The studies were scored on methodological quality using the Quality Assessment of Diagnostic Accuracy Studies tool (QUADAS-2). Data on sensitivity and specificity were subsequently extracted. RESULTS: The literature search revealed 583 articles, of which two prospective and six retrospective cohort studies were eligible for inclusion in the qualitative analysis. All studies documented methods suitable for the prenatal diagnosis of vasa previa. Four out of the eight studies used transvaginal ultrasound (TVS) for primary evaluation, while the remaining four studies used transabdominal ultrasound and performed a subsequent TVS when vasa previa was suspected. The QUADAS-2 tool reflected poor methodology in six of the eight included studies, and prenatal detection rates varied from 53% (10/19) to 100% (total of 442,633 patients, including 138 cases of vasa previa). In the two prospective studies (n = 33,795, including 11 cases of vasa previa), transvaginal color Doppler performed during the second trimester detected all cases of vasa previa (sensitivity, 100%) with a specificity of 99.0-99.8%. CONCLUSION: The accuracy of ultrasound in the diagnosis of vasa previa is high when performed transvaginally in combination with color Doppler.

Sonographic measurement of lower uterine segment thickness to predict uterine rupture during a trial of labor in women with previous Cesarean section: a meta-analysis.

OBJECTIVE: To evaluate the accuracy of antenatal sonographic measurement of lower uterine segment (LUS) thickness in the prediction of risk of uterine rupture during a trial of labor (TOL) in women with a previous Cesarean section (CS). METHODS: PubMed and EMBASE were searched to identify articles published on the subject of sonographic LUS measurement and occurrence of a uterine defect after delivery. Four independent researchers performed identification of papers and data extraction. Selected studies were scored on methodological quality, and sensitivity and specificity of measurement of LUS thickness in the prediction of a uterine defect were calculated. We performed bivariate meta-analysis to estimate summary receiver-operating characteristics (sROC) curves. RESULTS: We included 21 studies with a total of 2776 analyzed patients. The quality of included studies was good, although comparison was difficult because of heterogeneity. The estimated sROC curves showed that measurement of LUS thickness seems promising in the prediction of occurrence of uterine defects (dehiscence and rupture) in the uterine wall. The pooled sensitivity and specificity of myometrial LUS thickness for cut-offs between 0.6 and 2.0 mm was 0.76 (95% CI, 0.60-0.87) and 0.92 (95% CI, 0.82-0.97); cut-offs between 2.1 and 4.0 mm reached a sensitivity and specificity of 0.94 (95% CI, 0.81-0.98) and 0.64 (95% CI, 0.26-0.90). The pooled sensitivity and specificity of full LUS thickness for cut-offs between 2.0 and 3.0 mm was 0.61 (95% CI, 0.42-0.77) and 0.91 (95% CI, 0.80-0.96); cut-offs between 3.1 and 5.1 mm reached a sensitivity and specificity of 0.96 (95% CI, 0.89-0.98) and 0.63 (95% CI, 0.30-0.87). CONCLUSIONS: This meta-analysis provides support for the use of antenatal LUS measurements in the prediction of a uterine defect during TOL. Clinical applicability should be assessed in prospective observational studies using a standardized method of measurement.

Effect of 17-alpha hydroxyprogesterone caproate on cervical length in twin pregnancies.

OBJECTIVES: Previous studies on singleton pregnancies have indicated that progestogens may reduce the rate of cervical shortening during pregnancy. The aim of this study was to investigate whether treatment with 17-alpha hydroxyprogesterone caproate (17-OHPC) has an effect on cervical shortening in twin pregnancies. METHODS: This was a secondary analysis of patients who had participated in a multicenter randomized clinical trial on the effectiveness of 17-OHPC in preventing preterm birth in multiple pregnancies (the AMPHIA-trial). We included all trial participants with a twin gestation who had undergone repeat cervical length measurements during pregnancy. We performed a separate analysis of women with repeat measurements in centers where this was standard protocol for multiple pregnancies. The rate of cervical shortening for both the 17-OHPC group and the placebo group was analyzed using a linear mixed model. RESULTS: Of the 671 patients who participated in the trial, 282 (42%) had a twin pregnancy and underwent two or more cervical length measurements. Of these women, 140 were monitored in centers where repeat measurements were standard protocol. We observed an overall reduction of cervical length from 44.3 mm at 14-18 weeks to 30.0 mm at 30-34 weeks' gestation. In the 17-OHPC group, cervical length decreased by 1.04 mm each gestational week, while this was 1.11 mm per week for the placebo group (P = 0.6). For the overall group, each 10% decrease in cervical length led to an increase in the risk of preterm birth (hazard ratio, 1.14; 95% CI, 1.08-1.21). CONCLUSION: In women with a twin pregnancy, there is progressive shortening of the cervix during pregnancy, regardless of 17-OHPC use.

Techniques for wound closure at caesarean section: a randomized clinical trial.

OBJECTIVE: It is unclear which technique for skin closure should be used at caesarean section (CS) in order to get the best cosmetic result. STUDY DESIGN: We conducted a randomized controlled trial to assess the cosmetic result of different techniques for skin closure after CS. A two-center single-blind randomized controlled trial was performed in The Netherlands. Women undergoing their first CS were eligible for the trial. In a factorial design, women were randomly allocated to (1) closure of the fat layer versus non-closure and (2) staples or intracutaneous stitches for skin closure. The cosmetic result was assessed using the Patient and Observer Scar Assessment Scale (POSAS). RESULTS: We included 124 women. In the stitches group 63% [39/62] women judged the scar as satisfactory, versus 63% [38/60] in the staples group (RR 1.01; 95% CI 0.64-1.6). When the subcutaneous fat layer was closed, 52% [33/63] of the women scored the scar as satisfactory, versus 75% [44/59] of the women in whom the fat layer was not separately closed (RR 0.53; 95% CI 0.32-0.89). This effect was independent of the subcutaneous thickness (p-value for interaction 0.64). Of the secondary outcomes, subcutaneous closure of the fat layer was associated with a longer admission time (median 4 days; IQR 3-5 versus 3 days; IQR 3-5, p-value 0.023). CONCLUSIONS: The choice of staples or stitches does not affect the cosmetic result after a caesarean section. Closing of the subcutaneous fat layer, however, negatively affects the cosmetic result and is associated with a longer admission time.

Genetic analysis of fetal nucleated red blood cells from CVS washings.

Chorionic villus sampling (CVS) is an established invasive prenatal diagnostic method for the detection of fetal chromosome aberrations. In 1-2% the karyotype result of CVS is inconclusive and follow-up confirmation will be required. To avoid another invasive procedure we examined fetal nucleated red blood cells (NRBCs) from CVS washings for genetic analysis. We analysed the washings of 20 chorionic villi samples of male fetuses. Fetal NRBCs were immunostained by an antibody against embryonic haemoglobin (HbE). FISH was performed with probes specific for the X and Y chromosome and the nucleus was counterstained with DAPI. Cells positive for the antibody, as well as for DAPI, were collected and stored by a semi-automated microscope. An operator reviewed those cells for their FISH signals. In 19 out of 20 CVS washings we found nucleated cells positive for HbE together with XY FISH signals. In none of the washings HbE positive cells with two X signals were found. Our results indicate that anti-HbE is a very specific antibody for identifying fetal NRBCs. NRBCs from CVS washings can be used as an additional fetal tissue for first trimester prenatal diagnosis.

The influence of fetal position on nuchal translucency thickness.

OBJECTIVE: To determine whether nuchal translucency thickness is influenced by the fetal position at ultrasound examination. SUBJECTS: Transabdominal ultrasound examination for pregnancy dating and measurement of nuchal translucency thickness was performed at 10-14 weeks' gestation in all women attending the antenatal clinic of our hospital. During the examination special attention was paid to a change in fetal position from prone to supine or vice versa. METHODS: For each fetus the nuchal translucency measurement was repeated when a positional change from prone to supine or vice versa was recorded. All measurements were recorded on hard copy. An image-scoring method was used and evaluated by three independent reviewers. RESULTS: Eighty-five fetuses were included in this study. The mean nuchal translucency for supine fetuses was 1.91 mm compared with 1.93 mm for prone fetuses. The mean quality-score was 6.54 for supine fetuses and 6.55 for prone fetuses. This difference was not statistically significant. CONCLUSION: Fetal position has no influence on the measurement of nuchal translucency.

Co-variables in first trimester maternal serum screening.

The objective of this study was to determined the influence of maternal weight, maternal smoking habits, gravidity, parity and fetal gender on the level of maternal serum marker used in first trimester screening for Down syndrome. A total of 2449 singleton unaffected pregnancies from two centres were studied. Maternal serum free beta-human chorionic gonadotrophin (hCG) and alpha-fetoprotein (AFP) concentrations had been measured in all pregnancies, and pregnancy associated plasma protein (PAPP)-A levels had been measured in 924. All results were expressed as multiples of the gestation specific median (MoM) values after regression, using each centre's own medians. Information on maternal weight was available in 2259 pregnancies, on self-reported current cigarette smoking in 1364 (of whom 117 (8.6%) were smokers), on gravidity in 1371, parity in 1303 and fetal gender in 253. All three markers showed a statistically significant negative association with maternal weight (p<0.0005) and in the subsequent analyses MoM values were weight adjusted using standard methods. The median PAPP-A level in smokers was 0.81 MoM, a significant reduction (p<0.005); free beta-hCG was also reduced (median 0.89 MoM) but not significantly (p=0.17), and AFP was unaltered. The median AFP level in primagravidas was highly significantly greater than that in gravid women (p<0.0005). In PAPP-A the reverse effect was seen but it did not reach statistical significance (p=0.15) and there was no effect for free beta-hCG. Results of a similar magnitude and direction were found for parity. The median level of free beta-hCG was higher (p=0.0005), and the median AFP lower in female pregnancies. Maternal weight and, for PAPP-A, maternal smoking are important first trimester screening co-variables. Gravidity, parity and fetal gender also seem to influence one or more first trimester markers.

Enrichment, identification and analysis of fetal cells from maternal blood: evaluation of a prenatal diagnosis system.

In this study we evaluated the performance of a system for the enrichment, identification and analysis of fetal cells in maternal peripheral blood. Blood samples were collected from women after chorionic villus sampling and enriched for the presence of nucleated erythrocytes using a three-step procedure, namely: (a) centrifugation to separate nucleated red blood cells (NRBCs) from the majority of red blood cells (RBCs) and white blood cells (WBCs); (b) selective lysis of the remaining maternal RBCs; (c) separating the NRBCs from the remaining WBCs in a three-layer density gradient. Fetal cells were identified by using a monoclonal antibody against the gamma-chain of fetal haemoglobin (anti-HbF) and a nuclear stain (DAPI). Additionally, to further increase the specificity of the identification, and to eliminate some of the undesired staining by maternal leukocytes, a fluorescent antibody (CD45) was added. The sex chromosome complement of the cells was determined by fluorescence in situ hybridization (FISH) with X and Y-specific probes and the results were compared with the karyotypes obtained after analysis of chorionic villi. Using the described method, in all cases where the woman was carrying a male fetus (n=18) at least one XY cell was found, while no male cells were found in women carrying a female fetus. However, in the majority of cases with a male fetus (n=11) female HbF positive cells were found indicating the presence of maternal nucleated erythrocytes. The study demonstrates that the combination of anti-HbF and CD45 is a useful, but not fully specific, marker for fetal NRBCs and that additional markers are needed.

Early pregnancy screening for fetal aneuploidy with serum markers and nuchal translucency.

We determined the aneuploidy detection rate achievable by early pregnancy screening with pregnancy associated plasma protein (PAPP)-A, free beta human chorionic gonadotrophin (hCG) and ultrasound nuchal translucency (NT) measurement. Women having prenatal diagnosis were scanned, and a blood sample was taken and stored. Stored samples were tested and a total of 37 were found to have Down syndrome, 8 to have Edwards syndrome and 255 were controls. Results were expressed in multiples of the gestation-specific median (MOM) value in the controls after regression and, for the serum markers, maternal weight adjustment. In Down syndrome the medians were for PAPP-A 0.63 MOM (95 per cent confidence interval (CI) 0.45-0.87); free beta-hCG 1.88 MOM (1.33-2.66); and NT 2.34 MOM (1.70-3.22). Using these parameters the expected detection rate for a 5 per cent false-positive rate for different marker combinations were: 55.3 per cent for PAPP-A and free beta-hCG; 68.4 per cent for NT alone; and 84.6 per cent for PAPP-A, free beta-hCG and NT. The median values for Edwards syndrome were: 0.17 MOM for PAPP-A; 0.18 MOM for free beta-hCG; and 2.64 MOM for NT. Early pregnancy screening with the combined measurement of maternal serum PAPP-A and free beta-hCG and fetal nuchal translucency could achieve a high Down syndrome detection rate.

Enlarged nuchal translucency and low serum protein concentrations as possible markers for Zellweger syndrome.

We present a case of a fetus in which an enlarged nuchal translucency was detected at 12 weeks' gestation. The karyotype was normal. Subsequent ultrasound examination showed no obvious fetal abnormalities apart from a mild pericardial effusion. Serum screening revealed very low concentrations of estriol and human chorionic gonadotropin. After birth the diagnosis of Zellweger syndrome was made. Nuchal translucency screening, estriol level identification and detailed ultrasound scanning may help to identify fetuses affected by this syndrome.

First-trimester non-invasive prenatal diagnosis of triploidy.

We report a case of fetal triploidy in which fetal nucleated red blood cells were isolated from the maternal peripheral circulation at 12 weeks' gestation. FISH analysis with X and Y specific probes revealed three hybridization signals for the X chromosomes in 14 cells. The karyotype as established after CVS was shown to be 69,XXX. Two other non-invasive first-trimester screening methods were also evaluated. The serum markers pregnancy-associated plasma protein A (PAPP-A) and the free beta-chain of chorionic gonadotrophin (free beta-hCG) were both shown to be decreased in the same blood sample. An enlarged nuchal translucency (5 mm > or =95th centile) was seen at 13+2 weeks of gestation.

Weekly nuchal translucency measurements in normal fetuses.

OBJECTIVE: To examine the longitudinal course of nuchal translucency thickness by weekly measurements between 10 and 15 weeks' gestation in normal fetuses. METHODS: Nuchal translucency was measured weekly from 10 to 15 weeks' gestation in 64 fetuses with normal pregnancy outcome. The median and the fifth, 25th, 75th, and 95th percentiles were calculated. RESULTS: Nuchal translucency measurements varied considerably with gestational age; this variation followed a fetus-specific pattern. In 94% of cases, we observed an increase followed by a steady decrease in nuchal translucency measurement. A visible nuchal translucency was found after 76 and 86 days' gestation in 97% (95% confidence interval [CI] 89, 100) and 100% (95% CI 94, 100) of the fetuses, respectively. The median nuchal translucency increased from 0.7 mm at 70 days' gestation to 1.7 mm at 91 days' gestation, after which it declined to 1.0 mm at 105 days' gestation. CONCLUSION: A progressive increase and subsequent decrease in nuchal translucency thickness occurs with advancing gestation in most fetuses, but the timing of the peak thickening appears to be fetus-specific. In this study, each fetus developed a visible nuchal translucency. If the nuchal translucency measurement is 0 mm before 12 weeks, it may be advisable to repeat the measurement at 12 weeks' gestation. In contrast, a nuchal translucency that cannot be measured from 12 weeks' gestation onward suggests that this temporary anatomic entity is already in its waning phase.