Case history / examination
A 38‐year‐old patient, gravida 2, para 1 was referred to our hospital at 9 weeks of gestation following in vitro fertilization. Her past history included moyamoya disease. Delivery with epidural anaesthesia had been recommended by the neurosurgeon. Her family history noted that her father had died of moyamoya disease. At the second trimester screening, the placenta was attached on the anterior uterine wall. A low‐lying placenta, succenturiate lobe, and/or multilobed placenta was not identified. The umbilical cord insertion was marginal. The site of the umbilical cord insertion was on the lower side of the placenta. Both the placental position and the site of umbilical cord insertion were above the upper end of the bladder. At that time, vasa praevia was not suspected. At 37 weeks of gestation, gestational hypertension occurred. Elective delivery of the pregnancy was required. Transvaginal ultrasound without colour doppler did not reveal an abnormal image between the foetal head and the internal cervical os (Figure 1A). However, ultrasound with colour doppler was performed in order to exclude for abnormal insertion of the umbilical cord before introduction of a transcervical balloon catheter for cervical ripening. A few foetal vessels were found between the foetal head and the internal cervical os by using colour and pulse doppler (Figure 1B, 1C).