Clinical Edge Journal Scan

Commentary: Hypertension, morbidity in MTOP, and hypothyroidism risk in obstetric emergencies, November 2022

Dr. Rigby scans the journals, so you don't have to!


Fidelma Rigby, MD

This month's selection of obstetric emergencies research includes several clinically relevant and high-quality studies. We review a possible new role for low-dose aspirin in patients with chronic hypertension, examine the role of extended-release (ER) nifedipine in preeclampsia with severe features (preE with SF), look at the most common morbidities in medical terminations of pregnancy (MTOP) after 20 weeks, and examine the risk for neonatal hypothyroidism after CT pulmonary angiography.

Richards and colleagues explored the effects of aspirin prophylaxis in women with chronic hypertension. They did not detect a lowered risk for preeclampsia but did note a significantly decreased risk for preterm birth in the aspirin group. This was a systematic review and meta-analysis of nine studies (including retrospective cohort and randomized controlled trials). The mixed quality of the source data did limit the meta-analysis. However, this finding suggests that further research is warranted, and we may have a new role for aspirin in helping to decrease preterm birth in women with chronic hypertension.

Cleary and colleagues investigated the use of 30 mg oral nifedipine ER given every 24 hours until delivery in patients with preE with SF. In this randomized, triple-blinded, placebo-controlled trial, 110 patients were randomly assigned to nifedipine treatment or placebo. The results suggest a role for this medication early in the treatment of preE with SF, as the treated patients were much less likely to require acute therapy for severe-range blood pressure. The researchers also noted a trend toward fewer cesarean deliveries (20.8% vs 34.7%) and lower neonatal intensive care unit admissions (29.1% vs 47.1%) in the nifedipine ER group. This favors the use of nifedipine ER in patients with preE with SF.

Stewart and colleagues examined the more common morbidities associated with MTOP after 20 weeks estimated gestational age using a 10-year retrospective cohort study involving 407 patients. They found that 99% of the women had a successful vaginal delivery; however, 25% had some morbidity. Additionally, 16% of the women needed manual removal of placental tissue, 11% had postpartum hemorrhage, and 1.3% experienced severe maternal morbidity (including amniotic fluid embolism), but no maternal deaths occurred. Increased surveillance for postpartum hemorrhage in this patient population should be considered.

Righini and colleagues provide reassurance regarding a commonly used test to rule out pulmonary embolism in pregnant women. They present ancillary data from a prospective management outcome study of 149 women who underwent CT pulmonary angiography testing in pregnancy. There have been concerns raised regarding potential harmful effects related to intravenous iodinated contrast agents on thyroid function. None of the infants born to these patients had evidence of neonatal hypothyroidism (assessed via thyroid-stimulating hormone measurements). This gives reassurance that the use of CT pulmonary angiography testing for pulmonary embolism in pregnancy is safe.

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