Editorial

Obstetric remains one of the few disciplines where ultrasound still holds significant influence in clinical practice. At the end of 2016, as a deputy editor of this journal, I had persuaded the editorial team to take on the assignment of producing a special issue on obstetric. Following its conception and a long pregnancy it is pleasing to see that the idea has now borne fruit. This is that special issue. Here, we bring to you a review on an important subject and six papers on research besides the usual section on echoes.

Vasa previa occurs when the umbilical cord not only inserts into the surface membranes of the placenta rather than directly into the placenta (velamentous cord insertion) but its blood vessels lie low inside the uterus blocking or obstructing the cervical canal. These blood vessels then remain at a very high risk of rupturing during or before childbirth causing catastrophic life-threatening haemorrhage for the baby. The UK National Screening Committee (NSC) has published its recommendations in August 2017 and in this issue, Coleman and Venables’ review reinforces those recommendations. Colour Doppler transvaginal scan can be used for screening in high-risk pregnancies, for example in the case of multiple pregnancy, multiple gestation, low lying placenta, in-vitro fertilisation, accessory placental lobes, velamentous or marginal cord insertion. In the present circumstances and with our current scientific understanding, universal screening for vasa previa is not recommended.

Wiafe et al. report on their prospective study in 201 women in Ghana where they correlated transperineal ultrasound measured head–perineum distance, angle of progression, and head–symphysis distance with digital vaginal examination for fetal head station. Using station 0 as the level of head engagement, they found that the highest correlation was when the head–perineum distance was equal to or less than 3.6 cm where the sensitivity and specificity of sonographic determination of the engaged fetal head were 78.7 and 72.3%, respectively. Sepulveda and colleagues present a series of nine cases of splenic cyst in fetus which is a rare cause of congenital abdominal cyst. In their series, in about 50% of cases the cysts resolved and no complications were reported in the infants. However, quite understandably they mention that other possible causes of fetal cysts in the left upper abdominal quadrant should be considered and postnatal follow-up implemented. Milner and Arizina write on the familiar topic of discrepancy between ultrasound estimated fetal weight (EFW) and birth weight. Following their systematic review they mention about existence of random error with almost all methods of calculating EFW. Accuracy depends on number of incorporated parameters in the calculation of EFW and accuracy of measurements. Regular training and audit of activity should be the basis for achieving satisfactory competence in performing ultrasound measurement of fetal parts. Lim and colleagues from a tertiary referral centre present a case series of the very rare congenital cardiac anomaly, total anomalous pulmonary venous connection. Their review consists of 13 cases spanning over a period of 13 years. Antenatal diagnosis of this anomaly is difficult but essential for fully and satisfactorily informing parents in order to help decision making. Knight and colleagues based in a regional maternity unit have performed retrospective review of cases of in-vitro fertilisation (IVF). They compared ultrasound-calculated crown rump length gestational age taken at the routine First Trimester Screening Clinic (FTSC) with the ‘true’ gestational age calculated from the known IVF fertilization date. They found that ultrasound scan in FTSC using the current reference charts systematically overestimates gestational age. Their findings need to be confirmed in a larger prospective trial. Finally, Agarwal and colleagues present their work about prediction of preterm birth. They evaluated the role of new quantitative markers like elastography of cervix, fetal adrenal zone enlargement, and corrected fetal adrenal gland volume. Their findings suggest that these new markers may be helpful in the prediction of preterm birth.

I hope that you will enjoy reading this issue and that the wide variety of papers presented here will satisfy your interests. We must thank all our authors for their diligent and hard work in carrying out their research and submitting it in time for this special issue. Best wishes.