IMPORTANCE Severe early onset fetal growth restriction caused by placental dysfunction leads to high rates of perinatal mortality and neonatal morbidity. The phosphodiesterase 5 inhibitor, sildenafil, inhibits cyclic guanosine monophosphate hydrolysis, thereby activating the effects of nitric oxide, and might improve uteroplacental function and subsequent perinatal outcomes. OBJECTIVE To determine whether sildenafil reduces perinatal mortality or major morbidity. DESIGN, SETTING, AND PARTICIPANTS This placebo-controlled randomized clinical trial was conducted at 10 tertiary referral centers and 1 general hospital in the Netherlands from January 20, 2015, to July 16, 2018. Participants included pregnant women between 20 and 30 weeks of gestation with severe fetal growth restriction, defined as fetal abdominal circumference below the third percentile or estimated fetal weight below the fifth percentile combined with Dopplers measurements outside reference ranges or a maternal hypertensive disorder. The trial was stopped

Abstract-Fetal heart rate (fHR) monitoring is usually performed by Doppler ultrasound (US) techniques. For reliable fHR measurements it is required that the fetal heart is located within the US beam. In clinical practice, clinicians palpate the maternal abdomen to identify the fetal presentation and then the US transducer is fixated on the maternal abdomen where the best fHR signal can be obtained. Finding the optimal transducer position is done by listening to the strength of the Doppler audio output and relying on a signal quality indicator of the cardiotocographic (CTG) measurement system. Due to displacement of the US transducer or displacement of the fetal heart out of the US beam, the fHR signal may be lost. Therefore, it is often necessary that the obstetrician repeats the tedious procedure of US transducer positioning to avoid long periods of fHR signal loss. An intuitive US transducer positioning aid would be highly desirable to increase the work flow for the clinical staff. In this paper, the possibility to determine the fetal heart location with respect to the transducer by exploiting the received signal power in the transducer elements is shown. A commercially available US transducer used for fHR monitoring is connected to an US open platform, which allows individual driving of the elements and raw US data acquisition. Based on the power of the received Doppler signals in the transducer elements, the fetal heart location can be estimated. A beating fetal heart setup was designed and realized for validation. The experimental results show the feasibility of estimating the fetal heart location with the proposed method. This can be used to support clinicians in finding the optimal transducer position for fHR monitoring more easily.

Monitoring the uterine contractions provides important prognostic information during pregnancy and delivery. In particular, the propagation of uterine activity is closely related to the contraction efficiency. In the present study, a propagation analysis of uterine contraction is carried out by simultaneously recording the electrohysterogram (EHG) and the internal uterine pressure (IUP) on one woman in the last 4 hours of labor. The EHG, recorded in a monopolar multi-electrode configuration, was first processed in each channel in order to provide an accurate estimate of the IUP. The IUP estimate resulted in a correlation coefficient with the simultaneously recorded IUP r=0.74. Eventually, in order to evaluate the propagation of the muscular electrical activity, the delays among the IUP estimates in each channels were calculated by cross correlation function maximization. In agreement with previous studies, no preferred direction of propagation was singled out and pacemaker areas changed from contraction to contraction. However, by analyzing the occurrences of each pacemaker area, the uterine upper part resulted the most frequent location. Moreover, the close agreement between the number of simultaneously active electrodes and the IUP peak values (r=0.76) revealed a relationship between the spreading of action potentials and the maximum amplitude of contraction.

Abstract-Premature birth is a leading cause of fetal mortality and long-term morbidity. The effective treatment of preterm uterine contractions requires new methods for predicting delivery. The electrohysterographic (EHG) signal is a measure of the bioelectrical process underlying the uterine contraction. The analysis of parameters derived from the EHG signal can therefore provide fundamental information for the prognosis of labor. In this paper, we focus on the propagation of the EHG signal recorded during delivery by multiple electrodes. For the inter-electrode delay assessment and propagation analysis, two different methods are implemented. One is based on the prior estimation of the uterine mechanical activity by EHG signal processing. The delay is then calculated by the cross-correlation function between the mechanical activity estimated at each sensor. The other method is a high temporal resolution adaptive delay estimator that operates directly on EHG signals. The previously demonstrated accuracy of the mechanical estimates and the agreement between the delays provided by the methods confirm the tight relationship between the mechanical and electrical activity of the uterus. However, our results suggest that a higher temporal resolution delay estimator is preferred.

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