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OBJECTIVES: An increased nuchal translucency (NT) ≥3.5mm is a well-established marker for congenital anomalies and adverse pregnancy outcome between 11 and 14 weeks of gestation. Little is known about its performance as a screening tool before 11 weeks of gestation. We aimed to investigate in a prospective setting whether fetuses with an increased NT before 11 weeks of gestation are at risk for an adverse pregnancy outcome. METHODS: This is a prospective cohort study including pregnant women with a viable fetus with a NT≥2.5mm and a crown-rump-length (CRL) <45mm. All women were referred to our fetal medicine unit (FMU) and scheduled for a follow-up scan where the NT was remeasured after one week when the CRL was >45mm. Two groups were evaluated: cases with a normalized NT(<3.5mm) and cases with a persistently increased NT (≥3.5mm). We monitored the cases until four weeks after delivery. The main outcome was a composite adverse outcome of aneuploidies, other genetic disorders, structural anomalies and pregnancy loss. We performed subgroup analyses of NT thickness at inclusion and normalized or persistently increased NT at follow-up. RESULTS: We included 109 cases of which 35.8% (39/109) had an adverse pregnancy outcome. Of these 64.1% (25/39) were aneuploidies which corresponds to 22.9% (25/109) aneuploidies in total. The subgroups of NT thickness at inclusion of 2.5-3.4, 3.5-4.4 and ≥4.5mm showed abnormal outcomes in 22.0% (9/41), 40.0% (18/45), 52.2% (12/23) respectively. In fetuses with a normalized NT and without ultrasound abnormalities at follow-up scan, the incidence of adverse outcome was 8.5% (5/59), of which 5.1% (3/59) were aneuploidies. CONCLUSION: Fetuses with an early increased NT thickness are at considerable risk of an adverse pregnancy outcome, even if the NT normalizes after 11 weeks. Not all congenital anomalies can be diagnosed with routine first-trimester screening such as non-invasive prenatal testing and/or a first-trimester anomaly scan. Therefore, expectant parents should always be referred to a FMU for detailed ultrasonography. Invasive prenatal testing should be offered if an increased nuchal translucency of ≥2.5mm is observed before 11 weeks of gestation. This article is protected by copyright. All rights reserved.
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OBJECTIVE: Fetal premature atrial contractions (PACs) are usually benign, but are associated with congenital heart defects (CHDs) and tachyarrhythmias, which in turn carry a risk of cardiac failure and fetal death. We aimed to explore the frequency of adverse outcomes and to identify risk factors for tachyarrhythmias in pregnancies complicated by fetal PACs. METHODS: Fetuses diagnosed with PACs at two academic centres in Amsterdam between 2007 and 2022 were included in this retrospective cohort study. Cases with congenital anomalies or a prior diagnosis of CHD or other arrhythmias were excluded. M-mode and Doppler tracings were reanalysed and the PACs frequency recorded. We explored the incidence of adverse outcomes defined as: underlying CHDs not identified during the 20 weeks fetal anomaly scan, tachyarrhythmias, other arrhythmias, administration of antiarrhythmic therapy and death. Risk factors for tachyarrhythmias were analysed using odds ratios (OR). RESULTS: In 24% of the referred cases, PACs resolved before confirmation at the fetal medicine unit (FMU). Of the 939 included cases with proven PACs, the total incidence of adverse outcome was 6.8% (64/939). CHDs were diagnosed in 14 cases (1.5%, 95%-CI 0.9-2.5%) of which eight prenatally and six postnatally. Compared to baseline, the incidence of CHD in the presence of fetal PACs was increased (OR 1.8, 95%-CI 1.0-3.3, p=0.034). Tachyarrhythmias occurred prenatally and/or postnatally in 32 cases (3.4%) of which eight (25.0%) showed signs of cardiac failure and in 23 (71.9%) antiarrhythmic therapy was required. None of the tachyarrhythmias led to fetal or neonatal death. Risk factors for a tachyarrhythmia were: PACs with short runs of supraventricular tachycardia (OR 99), blocked PACs (OR 30), PACs in bigeminy (OR 22), frequent PACs (1 per 5-10 beats) (OR 6.9), signs of cardiac failure (OR 14) and the presence of a foramen ovale aneurysm (OR 5.0). CONCLUSIONS: PACs are generally benign and resolve often spontaneously. However, fetuses with irregular heart rate should be referred for advanced ultrasonography, which should focus on the type of PACs and risk classification. When risk factors for tachyarrhythmias are identified, weekly heart rate monitoring is advised until the PACs resolve. In the absence of risk factors, standard obstetric care may be sufficient with additional instructions to report reduced fetal movements. Should tachyarrhythmias or cardiac failure develop, referral back to the FMU is then indicated. This article is protected by copyright. All rights reserved.
RESUMO
OBJECTIVE: Fetal heart-rate irregularities occur in 1-2% of pregnancies and are usually caused by premature atrial contractions (PAC). Although PAC are considered benign, they may be associated with cardiac defects and tachyarrhythmia. We aimed to determine the incidence of congenital heart defects (CHDs) and complications in fetuses with PAC. METHODS: This was a systematic review and meta-analysis conducted in accordance with the PRISMA statement for reporting items for systematic reviews and meta-analyses. MEDLINE and EMBASE were searched from 1990 to June 2021 to identify studies on fetuses with PAC. The primary outcome was CHD; secondary outcomes were complications using the endpoints supraventricular tachyarrhythmia (SVT), cardiac failure and intrauterine fetal demise. Meta-analysis of proportions was performed, subdivided into high-risk and low-risk populations based on reason for referral. Pooled incidences with 95% CIs were calculated. RESULTS: Of 2443 unique articles identified, 19 cohort studies including 2260 fetuses were included. The pooled incidence of CHD in fetuses with PAC was 2.8% (95% CI, 1.5-4.1%), when 0.6% is the incidence expected in the general population. The pooled incidence of CHD was 7.2% (95% CI, 3.5-10.9%) in the high-risk population and 0.9% (95% CI, 0.0-2.0%) in the low-risk population. SVT occurred in 1.4% (95% CI, 0.6-3.4%) of fetuses diagnosed with PAC. Cardiac failure was described in 16 fetuses (1.4% (95% CI, 0.5-3.5%)), of which eight were CHD-related. Intrauterine fetal demise occurred in four fetuses (0.9% (95% CI, 0.5-1.7%)) and was related to CHD in two cases. CONCLUSIONS: Our findings suggest that the risk of CHD in fetuses with PAC is 4-5 times higher than that in the general population. CHD was present more frequently in the high-risk population. Consequently, an advanced ultrasound examination to diagnose PAC correctly and exclude CHD is recommended. Complications of PAC are rare but can result in fetal demise, thus weekly fetal heart-rate monitoring remains advisable to enable early detection of SVT and to prevent cardiac failure. © 2022 The Authors. Ultrasound in Obstetrics & Gynecology published by John Wiley & Sons Ltd on behalf of International Society of Ultrasound in Obstetrics and Gynecology.
