Consensus protocol for management of early and late twin-twin transfusion syndrome: Delphi study

OBJECTIVE

Fetoscopic laser photocoagulation (FLP) is a well-established treatment for twin-twin transfusion syndrome (TTTS) between 16 and 26 weeks' gestation. High-quality evidence and guidelines regarding the optimal clinical management of very early (prior to 16 weeks), early (between 16 and 18 weeks) and late (after 26 weeks) TTTS are lacking. The aim of this study was to construct a structured expert-based clinical consensus for the management of early and late TTTS.

METHODS

A Delphi procedure was conducted among an international panel of experts. Participants were chosen based on their clinical expertise, affiliation and relevant publications. A four-round Delphi survey was conducted using an online platform and responses were collected anonymously. In the first round, a core group of experts was asked to answer open-ended questions regarding the indications, timing and modes of treatment for early and late TTTS. In the second and third rounds, participants were asked to grade each statement on a Likert scale (1, completely disagree; 5, completely agree) and to add any suggestions or modifications. At the end of each round, the median score for each statement was calculated. Statements with a median grade of 5 without suggestions for change were accepted as the consensus. Statements with a median grade of 3 or less were excluded from the Delphi process. Statements with a median grade of 4 were modified according to suggestions and reconsidered in the next round. In the last round, participants were asked to agree or disagree with the statements, and those with more than 70% agreement without suggestions for change were considered the consensus.

RESULTS

A total of 122 experts met the inclusion criteria and were invited to participate, of whom 53 (43.4%) agreed to take part in the study. Of those, 75.5% completed all four rounds. A consensus on the optimal management of early and late TTTS was obtained. FLP can be offered as early as 15 weeks' gestation for selected cases, and can be considered up to 28 weeks. Between 16 and 18 weeks, management should be tailored according to Doppler findings.

CONCLUSIONS

A consensus-based treatment protocol for early and late TTTS was agreed upon by a panel of experts. This protocol should be modified at the discretion of the operator, according to their experience and the specific demands of each case. This should advance the quality of future studies, guide clinical practice and improve patient care. © 2023 International Society of Ultrasound in Obstetrics and Gynecology.

Association of intraplacental oxygenation patterns on dual-contrast MRI with placental abnormality and fetal brain oxygenation

OBJECTIVES

Most human in-vivo placental imaging techniques are unable to distinguish and characterize various placental compartments, such as the intervillous space (IVS), placental vessels (PV) and placental tissue (PT), limiting their specificity. We describe a method that employs T2* and diffusion-weighted magnetic resonance imaging (MRI) data to differentiate automatically placental compartments, quantify their oxygenation properties and identify placental lesions (PL) in vivo. We also investigate the association between placental oxygenation patterns and fetal brain oxygenation.

METHODS

This was a prospective study conducted between 2018 and 2021 in which dual-contrast clinical MRI data (T2* and diffusion-weighted MRI) were acquired from patients between 20 and 38 weeks' gestation. We trained a fuzzy clustering method to analyze T2* and diffusion-weighted MRI data and assign placental voxels to one of four clusters, based on their distinct imaging domain features. The new method divided automatically the placenta into IVS, PV, PT and PL compartments and characterized their oxygenation changes throughout pregnancy.

RESULTS

A total of 27 patients were recruited, of whom five developed pregnancy complications. Total placental oxygenation level and T2* did not demonstrate a statistically significant temporal correlation with gestational age (GA) (R²  = 0.060, P = 0.27). In contrast, the oxygenation level reflected by T2* values in the placental IVS (R²  = 0.51, P = 0.0002) and PV (R²  = 0.76, P = 1.1 × 10^-7 ) decreased significantly with advancing GA. Oxygenation levels in the PT did not show any temporal change during pregnancy (R²  = 0.00044, P = 0.93). A strong spatial-dependent correlation between PV oxygenation level and GA was observed. The strongest negative correlation between PV oxygenation and GA (R²  = 0.73, P = 4.5 × 10^-7 ) was found at the fetal-vessel-dominated region close to the chorionic plate. The location and extent of the placental abnormality were automatically delineated and quantified in the five women with clinically confirmed placental pathology. Compared to the averaged total placental oxygenation, placental IVS oxygenation level best reflected fetal brain oxygenation level during fetal development.

CONCLUSION

Based on clinically feasible dual-MRI, our method enables accurate spatiotemporal quantification of placental compartment and fetal brain oxygenation across different GAs. This information should improve our knowledge of human placenta development and its relationship with normal and abnormal pregnancy. © 2022 The Authors. Ultrasound in Obstetrics & Gynecology published by John Wiley & Sons Ltd on behalf of International Society of Ultrasound in Obstetrics and Gynecology.

Counseling in maternal-fetal medicine: SARS-CoV-2 infection in pregnancy

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is a zoonotic coronavirus that crossed species to infect humans, causing coronavirus disease 2019 (COVID-19). Despite a potentially higher risk of pregnant women acquiring SARS-CoV-2 infection compared with the non-pregnant population (particularly in some ethnic minorities), no additional specific recommendations to avoid exposure are needed in pregnancy. The most common clinical symptoms and laboratory signs of SARS-CoV-2 infection in pregnancy are fever, cough, lymphopenia and elevated C-reactive protein levels. Pregnancy is associated with a higher risk of severe SARS-CoV-2 infection compared with the non-pregnant population, including pneumonia, admission to the intensive care unit and death, even after adjusting for potential risk factors for severe outcomes. The risk of miscarriage does not appear to be increased in women with SARS-CoV-2 infection. Evidence with regards to preterm birth and perinatal mortality is conflicting, but these risks are generally higher only in symptomatic, hospitalized women. The risk of vertical transmission, defined as the transmission of SARS-CoV-2 from the mother to the fetus or the newborn, is generally low. Fetal invasive procedures are considered to be generally safe in pregnant women with SARS-CoV-2 infection, although the evidence is still limited. In pregnant women with COVID-19, use of steroids should not be avoided if clinically indicated; the preferred regimen is a 2-day course of dexamethasone followed by an 8-day course of methylprednisolone. Non-steroidal anti-inflammatory drugs may be used if there are no contraindications. Hospitalized pregnant women with severe COVID-19 should undergo thromboprophylaxis throughout the duration of hospitalization and at least until discharge, preferably with low molecular weight heparin. Hospitalized women who have recovered from a period of serious or critical illness with COVID-19 should be offered a fetal growth scan about 14 days after recovery from their illness. In asymptomatic or mildly symptomatic women who have tested positive for SARS-CoV-2 infection at full term (i.e. ≥ 39 weeks of gestation), induction of labor might be reasonable. To date, there is no clear consensus on the optimal timing of delivery for critically ill women. In women with no or few symptoms, management of labor should follow routine evidence-based guidelines. Regardless of COVID-19 status, mothers and their infants should remain together and breastfeeding, skin-to-skin contact, kangaroo mother care and rooming-in throughout the day and night should be practiced, while applying necessary infection prevention and control measures. Many pregnant women have already undergone vaccination, mostly in the USA where the first reports show no significant difference in pregnancy outcomes in pregnant women receiving SARS-CoV-2 vaccination during pregnancy compared with the background risk. Vaccine-generated antibodies were present in the umbilical cord blood and breast milk samples of pregnant and lactating women who received the mRNA COVID-19 vaccine. Based on the available limited data on the safety of the COVID-19 vaccine in pregnancy, it seems reasonable to offer the option of vaccination to pregnant women after accurate counseling on the potential risk of a severe course of the disease and the unknown risk of fetal exposure to the vaccine. © 2021 International Society of Ultrasound in Obstetrics and Gynecology.

Risk factors for Cesarean delivery in pregnancy with small-for-gestational-age fetus undergoing induction of labor

OBJECTIVES

To identify risk factors for Cesarean delivery and non-reassuring fetal heart tracing (NRFHT) in pregnancies with a small-for-gestational-age (SGA) fetus undergoing induction of labor and to design and validate a prediction model, combining antenatal and intrapartum variables known at the time of labor induction, to identify pregnancies at increased risk of Cesarean delivery.

METHODS

This was a retrospective cohort study of non-anomalous, singleton gestations with a SGA fetus that underwent induction of labor, delivered in a single tertiary referral center between January 2011 and December 2016. SGA was defined as estimated fetal weight (EFW) < 10^th percentile. The primary outcome was to identify risk factors associated with Cesarean delivery. The secondary outcome was to identify risk factors associated with NRFHT. Univariate and multivariate analyses were used to determine which clinical characteristics, available at the time of admission, had the strongest association with Cesarean delivery and NRFHT during labor induction. The predictive value of the final models was assessed by the area under the receiver-operating-characteristics curve (AUC). Sensitivity and specificity of the models were also assessed. Internal validation of the models was performed using 10 000 bootstrap replicates of the original cohort. The adequacy of the models was evaluated using the Hosmer-Lemeshow goodness-of-fit test.

RESULTS

A total of 594 pregnancies were included. Cesarean delivery was performed in 243 (40.9%) pregnancies. Significant risk factors associated with Cesarean delivery, and included in the final model, were maternal age, gestational age at delivery and initial method of labor induction. The bootstrap estimate of the AUC of the final prediction model for Cesarean delivery was 0.82 (95% CI, 0.78-0.86). The model had sensitivity of 64.2%, specificity of 86.9%, positive likelihood ratio (LR) of 4.9 and negative LR of 0.41. The model had good fit (P = 0.617). NRFHT complicated 117 (19.7%) pregnancies. Significant risk factors for NRFHT included EFW < 5^th percentile, abnormal umbilical artery Doppler studies (pulsatility index > 95^th percentile or absent/reversed end-diastolic flow) and gestational age at delivery. The final prediction model for NRFHT had an AUC of 0.69 (95% CI, 0.63-0.75) and specificity of 97.0%.

CONCLUSION

We identified several significant risk factors for Cesarean delivery and NRFHT among SGA pregnancies undergoing induction of labor. Clinicians may use these risk factors to guide patient counseling and to help anticipate the potential need for operative delivery. Copyright © 2019 ISUOG. Published by John Wiley & Sons Ltd.

Risk of miscarriage following amniocentesis or chorionic villus sampling: systematic review of literature and updated meta-analysis

OBJECTIVE

To estimate the procedure-related risk of miscarriage after amniocentesis and chorionic villus sampling (CVS) based on a systematic review of the literature and an updated meta-analysis.

METHODS

A search of MEDLINE, EMBASE and The Cochrane Library was carried out to identify studies reporting complications following CVS or amniocentesis. Eligible for inclusion were large controlled studies reporting data for pregnancy loss prior to 24 weeks' gestation. Study authors were contacted when required to identify additional necessary data. Data for cases that had an invasive procedure and controls were inputted into contingency tables and the risk of miscarriage was estimated for each study. Summary statistics based on a random-effects model were calculated after taking into account the weighting for each study included in the systematic review. Procedure-related risk of miscarriage was estimated as a weighted risk difference from the summary statistics for cases and controls. Subgroup analyses were performed according to the similarity in risk levels for chromosomal abnormality between the invasive-testing and control groups. Heterogeneity was assessed using the I² statistic. Egger's bias was estimated to assess reporting bias in published studies.

RESULTS

The electronic search yielded 2943 potential citations, from which 12 controlled studies for amniocentesis and seven for CVS were selected for inclusion in the systematic review. A total of 580 miscarriages occurred following 63 723 amniocentesis procedures, resulting in a weighted risk of pregnancy loss of 0.91% (95% CI, 0.73-1.09%). In the control group, there were 1726 miscarriages in 330 469 pregnancies with a loss rate of 0.58% (95% CI, 0.47-0.70%). The weighted procedure-related risk of miscarriage following amniocentesis was 0.30% (95% CI, 0.11-0.49%; I²  = 70.1%). A total of 163 miscarriages occurred following 13 011 CVS procedures, resulting in a risk of pregnancy loss of 1.39% (95% CI, 0.76-2.02%). In the control group, there were 1946 miscarriages in 232 680 pregnancies with a loss rate of 1.23% (95% CI, 0.86-1.59%). The weighted procedure-related risk of miscarriage following CVS was 0.20% (95% CI, -0.13 to 0.52%; I²  = 52.7%). However, when studies including only women with similar risk profiles for chromosomal abnormality in the intervention and control groups were considered, the procedure-related risk for amniocentesis was 0.12% (95% CI, -0.05 to 0.30%; I²  = 44.1%) and for CVS it was -0.11% (95% CI, -0.29 to 0.08%; I²  = 0%).

CONCLUSIONS

The procedure-related risks of miscarriage following amniocentesis and CVS are lower than currently quoted to women. The risk appears to be negligible when these interventions were compared to control groups of the same risk profile. Copyright © 2019 ISUOG. Published by John Wiley & Sons Ltd.

Perinatal mortality, timing of delivery and prenatal management of monoamniotic twin pregnancy: systematic review and meta-analysis

OBJECTIVE

To quantify the rate of perinatal mortality in monochorionic monoamniotic (MCMA) twin pregnancies, according to gestational age, and to ascertain the incidence of mortality in pregnancies managed as inpatients compared with those managed as outpatients.

METHODS

MEDLINE, EMBASE and CINAHL databases were searched for studies on monoamniotic twin pregnancy. The primary outcomes explored were the incidence of intrauterine death (IUD), neonatal death (NND) and perinatal death (PND) in MCMA twins at different gestational-age windows (24-30, 31-32, 33-34, 35-36 and ≥ 37 weeks of gestation). The secondary outcomes were the incidence of IUD, NND and PND in MCMA twins according to the type of fetal monitoring (inpatient vs outpatient), and the incidence of delivery ahead of schedule. Random-effects model meta-analyses were used to analyze the data.

RESULTS

Twenty-five studies (1628 non-anomalous twins reaching 24 weeks of gestation) were included. Single and double intrauterine deaths occurred in 2.5% (95% CI, 1.8-3.3%) and 3.8% (95% CI, 2.5-5.3%) of cases, respectively. IUD occurred in 4.3% (95% CI, 2.8-6.2%) of twins at 24-30 weeks, in 1.0% (95% CI, 0.6-1.7%) at 31-32 weeks and in 2.2% (95% CI, 0.9-3.9%) at 33-34 weeks of gestation, while there was no case of IUD, either single or double, from 35 weeks of gestation. In MCMA twin pregnancies managed mainly as inpatients, the incidence of IUD was 3.0% (95% CI, 1.4-5.2%), while the corresponding figure for those managed mainly as outpatients was 7.4% (95% CI, 4.4-11.1%). Finally, 37.8% (95% CI, 28.0-48.2%) of MCMA pregnancies were delivered before the scheduled time, due mainly to spontaneous preterm labor or abnormal cardiotocographic findings.

CONCLUSIONS

MCMA twins are at high risk of perinatal loss during the third trimester of pregnancy, with the large majority of such losses occurring as apparently unexpected events. Inpatient management seems to be associated with a lower rate of mortality, although further studies are needed in order to establish the appropriate type and timing of prenatal assessment in these pregnancies. Copyright © 2018 ISUOG. Published by John Wiley & Sons Ltd.

Vaginal symptoms and bacterial vaginosis (BV): how useful is self-report? Development of a screening tool for predicting BV status

Vaginal complaints compel an evaluation of bacterial vaginosis (BV), however, many cases of BV are asymptomatic. We evaluated the sensitivity and specificity of vaginal symptoms in the diagnosis of BV and examined the utility of creating a BV screening tool using clinical, behavioural and demographic characteristics. A total of 1916 pregnant women were included in this analysis. In total, 757 women screened positive for BV and over one third of BV-positive women presented without any lower genital tract symptoms (39.4%). African American race, abnormal vaginal odour, and smoking were independently related to BV positivity. A BV screening tool including these three factors was fairly predictive of BV status with the area under the ROC curve equal to 0.669. This three-item prediction rule may be useful in identifying high- risk pregnant women in need of BV screening and, given the high specificity, accurately identify the group of BV-negative pregnant women.

Characteristics and outcome of deliveries by forceps after failed ventouse

With the increasing use of the ventouse, it is becoming common for deliveries to be completed by the application of forceps. We present 48 cases delivered by forceps after a failed ventouse and compare these with 63 cases delivered by forceps only. There was significantly higher incidence of caesarean sections and cephalhaematoma in the group where forceps delivery was attempted after a failed ventouse compared to those delivered with forceps only.

Clinical and ultrasonographic features of dextroposition of the fetal heart

OBJECTIVE

Our purpose was to characterize the findings associated with dextroposition of the fetal heart.

STUDY DESIGN

A fetal echocardiography database was retrospectively searched from January 1990 through December 1996 to identify all cases referred or diagnosed with dextroposition of the fetal heart. Dextroposition was defined as most of the normally connected fetal heart found on the right side of the fetal chest. Intracardiac and extracardiac fetal anomalies were reviewed. All available karyotypes and postnatal examinations were reviewed.

RESULTS

During the study period 2882 fetal echocardiograms were performed, of which 297 (10.3%) were abnormal. Of these, 14 had dextroposition. Associated anomalies included atrioventricular canal (29%), diaphragmatic hernia (21%), and aneuploidy (14%). Isolated dextroposition with no other significant anomalies was seen in only 1 case. In another, no anomalies were noted except for suspected agenesis of 1 lobe of the right lung; karyotype and postnatal evaluation revealed no other abnormalities in both cases.

CONCLUSIONS

Dextroposition of the fetal heart was seen in 0.5% of our fetal echocardiograms and was associated with significant anomalies in 86% of our cases. When diagnosed, a targeted ultrasonogram, fetal echocardiogram, and karyotype should be offered.

Iatrogenic monoamniotic twins as a complication of therapeutic amniocentesis

BACKGROUND

Therapeutic amniocentesis has been accepted widely as a safe and efficacious way to treat the polyhydramnios-oligohydramnios sequence associated with twin-twin transfusion syndrome.

CASE

A 28-year-old woman, gravida 2, para 1, diagnosed with twin-twin transfusion syndrome at 28 weeks' gestation was treated with serial amniocenteses. The dividing membrane was ruptured inadvertently during therapeutic amniocentesis, with subsequent complete disruption of the amniotic membrane. Iatrogenic monoamniotic twins with cord entanglement and knotting resulted.

CONCLUSION

Creation of monoamniotic twins by disruption of the dividing membrane can be a complication of therapeutic amniocentesis for twin-twin transfusion syndrome. Such disruption may result in the same morbidity and mortality that are seen in naturally occurring monoamniotic twins.

Prenatal determination of chorionicity in triplet pregnancy by ultrasonographic examination of the ipsilon zone

OBJECTIVE

To determine chorionicity in triplet pregnancies by ultrasonographic assessment of the ipsilon zone, the junction of the three interfetal membranes.

METHODS

The thickness of the component membranes in the ipsilon zone was studied to determine chorionicity in 28 triplet pregnancies, by retrospective examination of the ultrasonographic images taken at 9-24 weeks' gestation, and in 20 consecutive triplet pregnancies followed prospectively by targeted ultrasonography at 8-21 weeks' gestation. Prenatal ultrasonographic findings were compared with those obtained from the records of the infertility centers or referring hospitals (the number of gestational sacs and live embryos in each sac seen by transvaginal scanning at 6-7 weeks' gestation).

RESULTS

Of the 28 triplet pregnancies with appropriate images demonstrating the ipsilon zone, 22 were classified as trichorionic, five dichorionic, and one monochorionic. This classification was correct in all but one trichorionic pregnancy, which was misclassified as dichorionic. In the prospective subset (n = 20) there were 16 trichorionic and four dichorionic triplet pregnancies. The ipsilon zone was not present in one case in which the interfetal membrane did not intersect. In the remaining 19 pregnancies, there was a complete correlation between the findings at the ipsilon zone and transvaginal ultrasonography at 6-7 weeks.

CONCLUSION

Ultrasonographic assessment of the ipsilon zone is useful for predicting chorionicity in triplet pregnancies.

The lambda sign at 10-14 weeks of gestation as a predictor of chorionicity in twin pregnancies

Chorionicity was prospectively determined in 369 twin pregnancies by ultrasound at 10-14 weeks of gestation. Pregnancies were classified as monochorionic if there was a single placental mass in the absence of the lambda sign at the inter-twin membrane-placental junction, and dichorionic if there was a single placental mass but the lambda sign was present, or the placentas were not adjacent to each other. In 81 (22%) cases, the pregnancies were classified as monochorionic and in 288 (78%) as dichorionic. Pregnancy outcome was available in 279 cases and all 63 of these pregnancies classified as monochorionic resulted in the delivery of same-sex twins. Similarly, all 100 different-sex pairs were correctly classified as dichorionic. These findings demonstrate the high reliability of ultrasound examination at 10-14 weeks of gestation in determining chorionicity in twin pregnancies.

Single uterine entry for genetic amniocentesis in twin pregnancies

In 176 diamniotic twin pregnancies at 10-20 weeks of gestation, amniotic fluid for cytogenetic studies was successfully obtained from both sacs by the use of a single uterine entry. There were no cases of discordancy between sex at amniocentesis and birth. There were six pregnancies with fetal unbalanced chromosomal defects; in one pregnancy both fetuses were abnormal and in five pregnancies only one fetus was abnormal. The total fetal loss rate was 5.7% (20 of 352 fetuses), including six (1.7%) terminations or selective fetocides and 14 (4.0%) spontaneous deaths. In the 176 pregnancies there were five (2.8%) with no survivors, including one termination and four (2.3%) spontaneous miscarriages or intrauterine deaths. There are only two (1.1%) pregnancies in which amniocentesis could have contributed directly to the losses and therefore the procedure-related rate of fetal loss may be similar to that in singleton pregnancies. The median gestation at delivery was 37 (range 16-40) weeks and delivery before 32 weeks occurred in 9% of the pregnancies. The birth weight distribution was similar to that reported in singleton pregnancies. This study demonstrates that in twin pregnancies amniotic fluid for cytogenetic studies can be obtained successfully from both sacs by use of a single uterine entry. The risk of fetal loss from this procedure appears to be similar to that in singleton pregnancies.