18th World Congress in Fetal Medicine
A case of large subchorionic hematoma with a normal pregnancy outcome Abdullahi H, Sinha P, Kalache K Sidra Medicine, Doha, Qatar
Objective The incidence of large subchorionic hematoma (SCH) is about 1: 2000. Intra-uterine hematomas are generally divided into three types according to their locations: sub-chorionic (between the myometrium and the placental membranes and/or at the margin of the placenta, 81%), retro placental (between the placenta and the myometrium, 16%), and preplacental (between the placenta and the amniotic fluid/placental membranes, 4%). SCH appears to result from tears of marginal veins, whereas placental abruption results from ruptures of spiral arteries. Therefore, placental impairment seems to be more serious in the retro placental hematoma than in the SCH. SCHs usually appear as hypoechoic or anechoic crescent-shaped areas on ultrasonography. Although the exact etiology is uncertain, they are believed to result from partial detachment of the chorionic membranes from the uterine wall.
Methods A 30 year old patient with three uncomplicated normal vaginal deliveries at term had routine antenatal care privately with normal ultrasound scans. She presented to the obstetric emergency department at 35 weeks’ gestation complaining of acute onset of palpitations and lower abdominal pain. She reported good fetal movements, no uterine contractions, no chest pain, gastrointestinal or urinary symptoms. On examination she had normal pulse, blood pressure and temperature. The uterus was soft, non tender, corresponding to dates, cephalic presentation. The CTG was normal. Urine dipstick showed 2+ blood; 3+ protein. Her symptoms settled spontaneously. The urine culture subsequently confirmed urinary tract infection with Group B streptococcus and she was started on oral antibiotics. Fetal ultrasound scan revealed normal growth with estimated fetal weight on the 70th centile, normal amniotic fluid volume and umbilical artery Doppler. The placenta position was anterior high, but there was large sub chorionic placental cyst measuring 10 x 10 cm with an intracystic structure suspicious of a hematoma, there were no signs of fetal anemia. The plan was for twice weekly ultrasound scans for Doppler and induction of labor at 38 weeks. Induction of labor was started at 38 weeks. She received two doses of prostaglandin vaginal tablets. The membranes ruptured spontaneously with a large amount of dark blood stained amniotic fluid. Labor was augmented with oxytocin infusion. She delivered by emergency caesarean section due to failure to progress at 4 cm dilatation and fetal heart decelerations. She delivered a female infant weighing 3kg, with Apgar scores of 5 at 1 minute and 8 at 10 min. Arterial and venous cord pH was 7.17 and 7.24 with base excess of - 7.9. The baby was demitted to the neonatal unit due to respiratory distress and suspected sepsis, treated with antibiotics for 48 hours until the cultures were reported as negative. Placental histopathology showed that the fetal surface had an area of 50 x 35 mm adjacent to the cord insertion with loosely adherent friable pale tissue consistent with subchorionic hematoma. The three vessel cord inserted 31 mm from the nearest edge of the placental disc. The maternal surface was normally lobated and unremarkable.
Results SCH has been reported to be complicated by intrauterine growth retardation and oligohydramnios. A meta-analysis demonstrated that SCH was associated with an increased risk of early and late pregnancy loss, abruption, and preterm premature rupture of membranes and that the presence of SCH increases the risk of early or late pregnancy loss by 2-fold. Among women who had SCH diagnosed in the first or second trimester and controls, there is a similar frequency of perinatal complications such as premature delivery, intrauterine growth retardation (IUGR), premature rupture of membranes (PROM), caesarean section, meconium stained fluid or the presence of late decelerations on CTG, Apgar score and birth weight.
Conclusion Ultrasonographically detected subchorionic hematoma had been associated with increased risk of miscarriage in patients with vaginal bleeding and threatened miscarriage during the first 20 weeks of gestation; however it does not affect the pregnancy outcome measures of ongoing pregnancies. The timing of delivery of such cases is very controversial especially when normal growth and Dopplers are reported. Induction of labor was started in our case to avoid possible pregnancy complications.