Uterine Hyperstimulation in Spontaneous Labor Leading to Concealed Abruption: A Case Report

S Nasir1, F Harris2

Manchester University NHS Foundation Trust, Wythenshawe Hospital, Obstetrics and Gynaecology, Manchester, United Kingdom

Objective:

Case report:

To report a case of a hyperstimulation in spontaneous labor and concealed

placental abruption. It aims to

Illustrate clinical decision-making in acute obstetric emergencies

Highlight the importance of early recognition of placental abruption

Provide educational tools for interpreting ambiguous CTGs

Discussion:

The pathological causes for spontaneous uterine tachysystole are

suspected chorioamnionitis (subclinical and clinical) and Antepartum

hemorrhage. It has been shown that in cases of placental abruption during

the 2-h period preceding delivery the CTG showed five or more

contractions in 10min, with a mean of 5.6. It is vital to appreciate that

tocolysis may not be appropriate in women with uterine tachysystole

secondary to placental abruption or chorioamnionitis, especially if there

is maternal tachycardia or hypotension.

37 years old, P0+3 (recurrent miscarriages) at 41w1d, Midwife led care, reported to maternity triage in spontaneous labor with abdominal

pain. On initial assessment, a good resting tone was noted with no dilatation. The patient was on Aspirin and stopped at 36 weeks, non-

smoker. On cardiotocography(CTG) 5-6 contractions were noted in 10 min for at least 20 minutes. Tocolytic Injection (terbutaline 250 mcg)

intramuscular given for tachysystole CTG. Dawes Redman criteria did not meet for 50 min. Doctor review was requested. CTG difficult to

interpret ? sinusoidal pattern, categorized as abnormal. Immediately bedside review was done and the patient disclosed absent fetal

movements for 3 hours. Abdominal palpation was tender, and exhibited 'woody' abdomen characteristics, vaginal examination: os closed,

posterior, no vaginal loss. Given the abnormal CTG and abdominal findings suggestive of placental abruption, verbally consented for

emergency cesarean section as CAT1, establishing IV line, and cross matching blood. Emergency buzzer for red transfer to theatre was

initiated. Consultant notified. The duration was 23 min from doctor’s review till delivery of baby. baby handed over to neonatal doctor. The

Apgar score was 5,8,9 and initial cord ph was 6.80 arterial with BE-23. Intraoperatively, placental abruption was confirmed by removing 400

mL retroplacental clots and placental histopathology. Management of the mother's uterine atony was carried out successfully with estimated

blood loss 900 ml.

Post-procedure: Patient was debriefed. Later the baby was transferred for cooling. On day 5 an MRI brain for the baby was done which

showed no signs of HIE before discharge with the establishment of good breastfeeding.

Conclusion:

Placental Abruption complicates 1% of pregnancies and is a leading

cause of perinatal morbidity and mortality. Presentation varies widely,

making the diagnosis sometimes challenging. It is vital to appreciate

that in a rapidly evolving hypoxia secondary to excessive uterine

activity, the baseline fetal heart rate may be increased (i.e., the “Zig Zag

Pattern”) due to an autonomic instability.

Therefore, any increase in uterine activity (i.e., frequency, duration,

strength, or the basal tone) associated with abnormalities in the fetal

heart rate should be considered as uterine hyperstimulation.

Retroplacental Clots

References:

Heinonen PK, Kajan M, Saarikoski S (1986) Cardiotocographic findings in abruptio placentae. European Journal of Obstetrics and Gynecology 23(1): 75-78.

Gracia Perez-Bonfils A, Vigneswaran K, Cuadras D, Chandraharan E (2019) Does the saltatory pattern on cardiotocograph (CTG) trace really exist? The ZigZag pattern as an alternative definition and its correlation with perinatal outcomes. J Matern Fetal Neonatal Med 13:1-9.

Tarvonen M, Hovi P, Sainio S, Vuorela P, Andersson S (2020) Intrapartum zigzag pattern of fetal heart rate is an early sign of fetal hypoxia: A large obstetric retrospective cohort study. Acta Obstet Gynecol Scand 27.

Contact Information:

Shahela.nasir@mft.nhs.uk

Fiona.harris@mft.nhs.uk