Case History A 17 year-old Caucasian primigravida presented to delivery suite at term + 5 days gestation in spontaneous labour with no ante natal risk factors. She had a normal 20 week anomaly scan and fetal growth in pregnancy had been assessed as appropriate via a customised chart.

She made good progress in labour. During the second stage of labour, fetal compromise was suspected and following appropriate assessment an instrumental delivery was performed using a kiwi ventouse.

Following easy delivery of the fetal head, shoulder dystocia was diagnosed and delivery facilitated using secondary manoeuvres. Despite the removal of both fetal arms, the fetus remained undelivered. Therefore the patient was taken to theatre for examination under general anaesthetic. An ultrasound scan demonstrated a large collection of fluid within the fetal abdomen and confirmed the absence of fetal heart pulsations.

Ultrasound guided trans-abdominal needle aspiration allowed 500 ml of meconium stained fluid to be removed and the baby to be delivered vaginally. Post mortem was declined and subsequent TORCH infection screen, placental morphology and paternal/fetal karyotype have all proven normal. Both parents have been screened for cystic fibrosis and found to be carriers.

Discussion A literature review found four cases of abdominal dystocia reported over the last 50 years. We postulate that meconium peritonitis, as a complication of cystic fibrosis, developed during this pregnancy, and was not detected as there was no indication for a third trimester scan.