Placental lakes vs lacunae: spot the differences.

Sonographic sonolucencies are anechoic areas surrounded by tissue of normal echogenicity, commonly found in the placental parenchyma during the second and third trimesters of pregnancy. The ultrasound appearance of lakes and lacunae derives from the low echogenicity of villous-free areas within the placental parenchyma, filled with maternal blood of varying velocities. In normal placentation, lakes usually start appearing as soon as maternal blood begins to flow freely within the intervillous space at the end of the first trimester, whereas, in accreta placentation, lacunae develop progressively during the second trimester. Larger lakes are found mainly in areas of lower villous density under the fetal plate or in the marginal areas, but can also be found in the center of a lobule above the entry of a spiral artery. Lakes of variable size, position and shape are of no clinical significance, except if they transform into echogenic cystic lesions, which have been associated with poor fetal growth and placental malperfusion. Lacunae are formed by the distortion of one or more placental lobules developing inside a uterine scar, resulting from high-volume, high-velocity flows from the radial/arcuate arteries, and are associated with a high probability of placenta accreta spectrum at birth. They often present with ultrasound signs of uterine remodeling following scarring. Lakes and lacunae can coexist within the same placenta and both will change in size and shape as pregnancy advances. Better understanding of the etiopathology of placental sonolucent spaces and associated morphological changes is necessary to identify patients at risk of subsequent complications during pregnancy and/or at delivery. © 2023 The Authors. Ultrasound in Obstetrics & Gynecology published by John Wiley & Sons Ltd on behalf of International Society of Ultrasound in Obstetrics and Gynecology.

Impact of placenta previa with placenta accreta spectrum disorder on fetal growth.

OBJECTIVES: To evaluate fetal growth in pregnancies complicated by placenta previa with or without placenta accreta spectrum (PAS) disorder, compared with in pregnancies with a low-lying placenta. METHODS: This was a multicenter retrospective cohort study of singleton pregnancies complicated by placenta previa with or without PAS disorder, for which maternal characteristics, ultrasound-estimated fetal weight and birth weight were available. Four maternal-fetal medicine units participated in data collection of diagnosis, treatment and outcome. The control group comprised singleton pregnancies with a low-lying placenta (0.5-2 cm from the internal os). The diagnosis of PAS and depth of invasion were confirmed at delivery using both a predefined clinical grading score and histopathological examination. For comparison of pregnancy characteristics and fetal growth parameters, the study groups were matched for smoking status, ethnic origin, fetal sex and gestational age at delivery. RESULTS: The study included 82 women with placenta previa with PAS disorder, subdivided into adherent (n = 35) and invasive (n = 47) PAS subgroups, and 146 women with placenta previa without PAS disorder. There were 64 controls with a low-lying placenta. There was no significant difference in the incidence of small-for-gestational age (SGA) (birth weight ≤ 10th percentile) and large-for-gestational age (LGA) (birth weight ≥ 90th  percentile) between the study groups. Median gestational age at diagnosis was significantly lower in pregnancies with placenta previa without PAS disorder than in the low-lying placenta group (P = 0.002). No significant difference was found between pregnancies complicated by placenta previa with PAS disorder and those without for any of the variables. Median estimated fetal weight percentile was significantly lower in the adherent compared with the invasive previa-PAS subgroup (P = 0.047). Actual birth weight percentile at delivery did not differ significantly between the subgroups (P = 0.804). CONCLUSIONS: No difference was seen in fetal growth in pregnancies complicated by placenta previa with PAS disorder compared with those without and compared with those with a low-lying placenta. There was also no increased incidence of either SGA or LGA neonates in pregnancies with placenta previa and PAS disorder compared with those with placenta previa with spontaneous separation of the placenta at birth. Adverse neonatal outcome in pregnancies complicated by placenta previa and PAS disorder is linked to premature delivery and not to impaired fetal growth. Copyright © 2019 ISUOG. Published by John Wiley & Sons Ltd.

Screening for morbidly adherent placenta in early pregnancy.

OBJECTIVE: To estimate the diagnostic accuracy of a two-stage strategy for early prediction of morbidly adherent placenta (MAP). In the first stage, at 11-13 weeks' gestation, women with low-lying placenta and history of uterine surgery are classified as being at high risk for MAP and, in the second stage, at 12-16 weeks, these high-risk pregnancies are assessed at a specialist MAP clinic. METHODS: This was a prospective study in women having an ultrasound scan at 11-13 weeks' gestation as a part of routine pregnancy care. Women with low-lying placenta and a history of uterine surgery were followed up at a specialist MAP clinic at 12-16 weeks' gestation, 20-24 weeks and 28-34 weeks. At each visit to the MAP clinic, an ultrasound scan was carried out and the following features suggestive of MAP were recorded: non-visible Cesarean section scar; bladder wall interruption; thin retroplacental myometrium; presence of intraplacental lacunar spaces; presence of retroplacental arterial-trophoblastic blood flow; and irregular placental vascularization demonstrated by three-dimensional power Doppler. RESULTS: Screening at 11-13 weeks was carried out in 22 604 singleton pregnancies, 1298 (6%) of which were considered to be at high risk of MAP because they had previous uterine surgery and low-lying placenta. At the MAP clinic at 12-16 weeks, the diagnosis of MAP was suspected in 14 cases and this was confirmed at delivery in 13. In the rest of the population, there were no cases of MAP. CONCLUSION: Accurate prediction of MAP can be achieved by ultrasound examination at 12-16 weeks' gestation. Copyright © 2018 ISUOG. Published by John Wiley & Sons Ltd.

Natural history of early first-trimester pregnancies implanted in Cesarean scars.

OBJECTIVE: To describe the ultrasound findings and natural history of pregnancies implanted within or on Cesarean section scars in the first trimester of pregnancy. METHODS: This was a prospective observational study of 10 women diagnosed with a pregnancy implanted in or on a Cesarean section scar in the first trimester, who declined medical intervention because of their desire to continue the pregnancy. The study population comprised women at < 12 weeks' gestation who were seen in our early pregnancy unit between January 2011 and September 2013. Nine women were followed up by serial ultrasound examinations and had detailed care plans for delivery at King's College Hospital (KCH). One woman was followed up and delivered at another teaching hospital. The first-trimester ultrasound findings were compared with the clinical outcome of the pregnancy. RESULTS: The nine patients who were followed up at KCH developed ultrasound findings of morbidly adherent placenta (MAP) in the second and third trimesters. All 10 patients were diagnosed with MAP at the time of delivery by Cesarean section. The gestational age at delivery ranged from 26 to 38 weeks. The uterus was conserved in five patients, and Cesarean hysterectomy was performed in the remaining five. All three women with complete implantation of the gestational sac within the scar and two of three cases with placental lakes in the first trimester had hysterectomies. The two cases with bulging of the gestational sac out of the uterine contour had a preterm emergency hysterectomy due to placenta percreta. Histology confirmed placenta accreta in the five hysterectomy specimens. There were no fetal or neonatal complications. CONCLUSIONS: Implantation of a pregnancy on or in a Cesarean section scar is a precursor of MAP; however, the degree of morbidity associated with this implantation is variable and difficult to predict based on first-trimester ultrasound findings only. The assessment of ongoing pregnancies implanted in Cesarean scars is most beneficial when performed between 7 and 9 weeks' gestation. Complete implantation within the myometrial defect, bulging of the trophoblast from the uterine contour and large placental lakes in the first trimester are ultrasound findings that may predict severe placenta accreta or percreta and consequently a poor outcome.

Prediction of early pregnancy viability in the absence of an ultrasonically detectable embryo.

OBJECTIVE: To identify clinical, ultrasound and biochemical parameters that may allow prediction of pregnancy viability in women without a detectable embryo on ultrasound examination. METHODS: This was a prospective observational study of pregnant women with an ultrasound finding of a gestational sac measuring < 20 mm mean diameter without a visible embryo. Women's age, menstrual dates, clinical symptoms (pain and bleeding), mean gestational sac diameter and measurements of serum beta-human chorionic gonadotropin and progesterone were recorded in all cases. All women were managed expectantly until the pregnancy viability was established conclusively based on clinical and ultrasound findings. All parameters were tested by univariate analysis and then analyzed in a stepwise procedure to form a logistic regression model for predicting pregnancy viability. RESULTS: One hundred and eighteen (59%) women had a normal intrauterine pregnancy and 82 (41%) had a miscarriage. Stepwise analysis showed that three diagnostic parameters (maternal age, gestational sac diameter and serum progesterone) contributed significantly to the predictive power of the logistic model. With this model, at a cut-off value of 10% probability, the diagnosis of viable pregnancy was made with a sensitivity of 99.2% (95% CI, 95.8-99.97) and specificity of 70.7% (95% CI, 61.3-78.9). CONCLUSION: The use of a logistic regression model allows prediction of pregnancy viability when an embryo cannot be visualized on ultrasound scan.

Fetal cardiac abnormalities identified prior to 14 weeks' gestation.

OBJECTIVE: An increasing number of patients are presenting at early gestational age as being at high risk for congenital heart disease, as a result of ultrasound screening by nuchal translucency. The feasibility and accuracy of fetal echocardiography was assessed in a series of pregnancies studied before 14 weeks' gestation. METHODS: Echocardiography was attempted in 478 fetuses of crown-rump length 40.0-85.0 mm (median, 60.3 mm) with increased nuchal translucency, suspected abnormalities on routine scan or a family history of heart defect. The findings were related to results of autopsy, karyotyping, later scans and postnatal follow-up. RESULTS: Satisfactory images were obtained transabdominally in 402/478 (84.1%) and transvaginally in a further 13 patients. Cardiac defects were confidently identified in 60 fetuses and abnormalities of uncertain significance (isolated ventricular or great artery disproportion, or tricuspid regurgitation) were observed in a further 49. Defects were suspected in an additional 20 fetuses, and 286 were passed as normal. The karyotype was subsequently demonstrated to be abnormal in 70/286 (24.5%) fetuses with normal echocardiograms, and in 94/129 (72.9%) with abnormal or suspicious cardiac findings. Validation of the scan findings was possible in 241 fetuses. Normal heart structure was confirmed in 204 fetuses, and previously unsuspected cardiac abnormalities revealed in nine. Heart defects were verified in 28 fetuses, but five of these had important additional findings. There were false positive findings in three fetuses. CONCLUSIONS: Fetal echocardiography is feasible prior to 14 weeks' gestation. Cardiac defects, when present, may be identified or suspected in the majority of cases. In the risk group studied, heart defects were frequently a manifestation of chromosomal abnormality.

A case of body stalk anomaly at 10 weeks of gestation.

We describe a case of body stalk anomaly which was diagnosed at 10 weeks of gestation on a dating scan. The fetus was visualized within the exocelomic cavity outside an apparently intact amniotic membrane. The fetus displayed multiple anomalies characteristic of body stalk syndrome including a skull and brain defect, abdominal wall defect, kyphoscoliosis and gross deformities of the lower limbs. These findings do not support early amniotic membrane rupture as the primary event in the pathogenesis of body stalk anomaly and indicate that the exocelomic location of the fetus may actually be one of the features of this complex developmental anomaly.

Incidence of major structural cardiac defects associated with increased nuchal translucency but normal karyotype.

OBJECTIVE: To examine the association between increased nuchal translucency thickness and major cardiac defects in chromosomally normal fetuses. SETTING: Tertiary referral unit for fetal medicine and fetal cardiology. METHODS: During a 4-year period (January 1997 to January 2001), detailed echocardiography was performed in 1319 chromosomally normal fetuses with increased nuchal translucency thickness at 10-14 weeks of gestation. The incidence of major cardiac defects was examined in relation to the fetal NT at the 10-14-week scan. RESULTS: Major cardiac defects were diagnosed in 60 (4.5%) of the 1319 fetuses. In fetuses with a nuchal translucency thickness in the range of 2.5-3.4 mm, the incidence of major cardiac defects was 2.5% (18/722; 95% confidence interval, 1.5-3.9) and in those with a nuchal translucency thickness > or =3.5 mm, it was 7% (42/597; 95% confidence interval, 5.1-9.4). CONCLUSION: Specialist echocardiography is indicated in all fetuses with increased nuchal translucency thickness because, in such fetuses, the incidence of major cardiac defects is substantially higher than in pregnancies with maternal diabetes, family history and exposure to drugs, where fetal echocardiography is widely considered to be necessary.

The expectant management of women with early pregnancy of unknown location.

OBJECTIVE: To assess the results of expectant management in women with pregnancy of unknown location and to identify diagnostic parameters that are predictive of spontaneous pregnancy resolution. DESIGN: Prospective, observational study. SUBJECTS: Women with a positive pregnancy test and suspected early pregnancy complications who were referred for ultrasound assessment. METHODS: Women were first examined by transvaginal ultrasound to establish the location and viability of pregnancy. All women with pregnancies that could not be located on the scan had a blood sample taken to quantify the serum human chorionic gonadotropin (hCG) and progesterone levels. Management was expectant until the pregnancy was identified, the condition resolved spontaneously or an intervention was required because clinical symptoms deteriorated or hCG levels did not decline. For each woman, age, clinical symptoms (pain and bleeding), menstrual dates, past gynecological history, endometrial thickness and levels of serum hCG and progesterone were recorded. All parameters were tested by univariate analysis and then analyzed in a stepwise procedure to form a logistic regression model for predicting spontaneous resolution of pregnancy. RESULTS: A total of 1625 women were included in the study. In 135 cases (8%) the location of pregnancy was unknown. Complete data sets were obtained in 127 cases. These included 34 (27%) normal intrauterine pregnancies, 11 (9%) miscarriages and 18 (14%) ectopic pregnancies. A total of 64 (50%) pregnancies resolved spontaneously. Stepwise analysis showed that four diagnostic parameters--vaginal bleeding, endometrial thickness, serum hCG level and progesterone level--contributed significantly to the predictive power of the logistic model. With the use of this model, spontaneous pregnancy resolution could be predicted at the initial visit with a sensitivity and specificity of 92%. CONCLUSIONS: The majority of pregnancies of unknown location are abnormal: many resolve spontaneously when managed expectantly. A logistic model may be used at the initial visit to identify those cases in which the pregnancy is likely to resolve without the need for intervention.

Early diagnosis of major cardiac defects in chromosomally normal fetuses with increased nuchal translucency.

OBJECTIVE: To determine the value of early ultrasound examination for prenatal diagnosis of cardiac defects in chromosomally normal fetuses with increased nuchal translucency thickness at 10-14 weeks of gestation. DESIGN: Prospective audit. SETTING: Fetal Medicine Centre. METHODS: Specialist fetal echocardiography was carried out in 398 chromosomally normal fetuses with a nuchal translucency measurement above the 99th centile (> or = 3.5 mm). In the first 75 pregnancies the cardiac scan was carried out at 17-22 weeks and the next 323 cases had one scan at 13-17 weeks and another at 20-22 weeks. Pregnancy outcome was obtained in all of the cases. RESULTS: Major cardiac defects were present in 29 (7.3% of 398) cases and in 28 of these the diagnosis was made by antenatal echocardiography. In 27 of the 29 fetuses with major cardiac defects echocardiography was carried out at 13-17 weeks and an abnormality was suspected in 24 of the cases (88%). CONCLUSIONS: Increased nuchal translucency in chromosomally normal fetuses is associated with an increased prevalence of major cardiac defects and, as such, is an indication for specialist fetal echocardiography. Most of the cardiac abnormalities are detectable on antenatal fetal echocardiography and many can be excluded by early scanning.

The effectiveness of non-surgical management of early interstitial pregnancy: a report of ten cases and review of the literature.

OBJECTIVE: To assess the effectiveness of non-surgical management of interstitial pregnancy. DESIGN: A prospective interventional study. SUBJECTS: Eleven women with the ultrasound diagnosis of interstitial ectopic pregnancy. METHODS: Women with suspected early pregnancy complications were examined by transvaginal ultrasound. Those with the diagnosis of interstitial pregnancy were offered non-surgical treatment with methotrexate, which was administered systemically or by local injection. Follow-up with regular measurements of beta-human chorionic gonadotropin and ultrasound scans continued until the pregnancy had resolved completely. RESULTS: Ten women were managed non-surgically, and one woman opted for surgery. Five women received systemic and five local methotrexate. Local therapy was successful in all five cases (100%), whereas four out of five (80%) women receiving systemic methotrexate were cured. Significant side-effects were noted in two women following systemic therapy. In comparison, there were no side-effects in the group of women who received local therapy. There were no significant differences between the two treatment groups in the length of time taken for the pregnancy to resolve. CONCLUSIONS: Non-surgical treatment of interstitial pregnancy with methotrexate appears to be safe and effective. Local administration appears to be more successful and better tolerated by patients and may be used as the first-line therapy.

Umbilical cord cysts in early pregnancy.

OBJECTIVE: To assess the prevalence, morphologic characteristics, and natural history of umbilical cord cysts detected by ultrasound in the first trimester of pregnancy. METHODS: This was an ultrasound screening study for the presence of umbilical cord cysts in 859 pregnant women with singleton live fetuses at 7-13 weeks' gestation. In all cases of cord cysts the scan was repeated fortnightly until the cyst resolved or a fetal abnormality was detected. All patients with ongoing pregnancies had detailed scans at 20 weeks. Infants and umbilical cords were examined after delivery for the presence of structural abnormalities. RESULTS: Umbilical cord cysts were present in 29 (3.4%) of the 859 pregnancies. Fetal abnormalities were found in seven (26%) of the 27 cases with ongoing pregnancies. The fetus was more likely to be abnormal if the cyst was located near the placental or fetal extremity of the cord (relative risk [RR] 3.3; 95% confidence interval [CI] 1.3, 8.5) or paraxially (RR 3.8; 95% CI 1.2, 12.0) or if it persisted beyond 12 weeks' gestation (RR 7.7; 95% CI 3.2, 18.6). CONCLUSIONS: The prevalence of umbilical cord cysts at 7-13 weeks' gestation is approximately 3%, and in more than 20% of cases there are fetal chromosomal or structural defects.

Selection and identification of standard cardiac views from three-dimensional volume scans of the fetal thorax.

The feasibility of fetal echocardiographic examination using three-dimensional ultrasonography was investigated in 54 healthy pregnant women with uncomplicated pregnancies between 17 and 37 weeks of gestation. In 46 cases (85.2%), good quality three-dimensional volumes of the fetal heart were obtained from both apical and lateral four-chamber views. By reslicing apical volumes, the reformatted sections of the long axis view of the left ventricle and the aortic crest were seen in 40 (87%) and 38 (83%) of 46 cases, respectively. The short axis was seen in 26 (57%) and ductal arch in 30 (65%) cases. The examination of lateral volumes was much less successful. The short axis was seen in 11 (24%) cases, and the aortic crest in 22 (48%), whereas the analysis of the longitudinal views was not possible. The best results were obtained at a gestational age between 22 and 27 weeks. Three-dimensional fetal echocardiography allowed the examination of the four chambers of the heart and left outflow tract during the late second trimester. The technique may become useful for the screening and diagnosis of congenital cardiac defects in the future.

Clinical and echographic features of in utero cardiac dysfunction in the recipient twin in twin-twin transfusion syndrome.

OBJECTIVE: Fetal twin-twin transfusion syndrome (TTTS) presenting in the second trimester has been associated with almost no perinatal survival until recently, when serial drainage of amniotic fluid has improved the prognosis to 70%-80%. Most recipient twins now survive but develop cardiac dysfunction. The study was undertaken to evaluate the abnormal echocardiographic features and clinical complications of cardiac disease in the recipient twin of TTTS. DESIGN: Antenatal and postnatal echocardiographic and clinical observational study. SETTING: Antenatal studies in a tertiary referral centre. Postnatal management and follow up were performed by the same paediatric cardiologist, either at the obstetric hospital or at the regional referral centre. PATIENTS: Twin pregnancies complicated by TTTS with severe polyhydramnios diagnosed earlier than 25 weeks that proceeded until viability (n = 5). INTERVENTION: Serial fetal echocardiography with colour Doppler. Postnatal echocardiography in the first week and between two and seven months. Serial amnioreduction was performed in all pregnancies. Digoxin treatment, pericardiocentesis, paracentesis, or laser ablation of placental anastomoses was undertaken when there was hydrops. RESULTS: Increased cardiothoracic ratio and tricuspid regurgitation were seen in all recipient twins. High pulmonary artery velocities developed in three. One recipient twin died a week after delivery of endocardial fibroelastosis and infundibular pulmonary stenosis. Two other had balloon dilatation for pulmonary stenosis, one shortly after birth and one at four months. A further twin has apical thickening of the right ventricle at six months. The remaining recipient twin had normal echocardiographic findings at follow up. CONCLUSION: This report characterises for the first time a cardiac disease acquired in utero in the recipient twin in pregnancies complicated by TTTS. Clinical manifestations in utero range from mild to critical pulmonary stenosis or lethal cardiomyopathy. Although perinatal prognosis seems to be related to the severity of dysfunction when first diagnosed in utero, follow up in infancy is recommended in view of the possibility of progressive pulmonary stenosis.

Direct fetal administration of immunoglobulins: another disappointing therapy in alloimmune thrombocytopenia.

Current management strategies to prevent fetal intracranial haemorrhage in perinatal alloimmune thrombocytopenia (PAIT) include serial platelet transfusion and/or maternal high-dose intravenous immunoglobulin (IVIG) administration. The former involves multiple invasive procedures, while the latter is both expensive and of questionable efficacy. We report the use of direct fetal IVIG in 2 fetuses with PAIT, undergoing serial intrauterine platelet transfusions. Fetal IVIG had no effect on fetal platelet count. We conclude that direct fetal IVIG administration does not appear to have a role in the management of PAIT, and that current management strategies remain far from ideal.

Fetal blood sampling from intrahepatic vein versus cord insertion: effect on pH and blood gases.

OBJECTIVE: To determine whether venous pH, base excess, and blood gas values collected by antenatal ultrasound-guided sampling from the fetal intrahepatic vein (intra-abdominal umbilical vein, portal sinus, or portal vein) differ from those obtained from the placental cord insertion. METHODS: Retrospective analysis was done of 1053 clinically indicated fetal blood sampling procedures performed between 1988-1992. One hundred sixty-eight appropriate for gestational age (AGA) singleton fetuses were identified after exclusion of those with conditions believed likely to have impaired fetal blood gas status. Fetal venous pH, carbon dioxide pressure, oxygen pressure, and base excess from 52 samplings at the intrahepatic vein were compared cross-sectionally to those from 116 samplings at the placental cord insertion, using analysis of covariance to correct for gestational age. RESULTS: There was no systematic difference in the blood gas or acid-base values between the two sites of fetal venous blood sampling. CONCLUSIONS: Acid-base and blood gas status in AGA fetuses is not affected by the site of sampling. Values obtained at the intrahepatic vein may be interpreted using reference ranges derived from sampling at the placental cord insertion.

Amiodarone given by three routes to terminate fetal atrial flutter associated with severe hydrops.

BACKGROUND: We describe the concurrent administration of amiodarone using three different routes in order to provide: 1) rapid and adequate fetal loading without giving unduly high doses to the mother, and 2) a maintenance dose to the fetus without risking repeated invasive procedures. CASE: Rapid atrial flutter was seen on ultrasound in a fetus with severe hydrops at 27 weeks' gestation. Following failed transplacental therapy with sotalol and flecainide, amiodarone was administered to the fetus via the intravenous, intraperitoneal, and transplacental routes. Conversion to sinus rhythm and resolution of hydrops followed this treatment. CONCLUSION: Combined triple-route administration of amiodarone to the fetus can be effective in treating supraventricular tachycardia and may have a role in the management of life-threatening fetal arrhythmias refractory to transplacental therapy.