Pathopharmacology of Excessive Hemorrhage in Mifepristone Abortions

Effector and Activated T Cells Induce Preterm Labor and Birth That Is Prevented by Treatment with Progesterone

Preterm labor commonly precedes preterm birth, the leading cause of perinatal morbidity and mortality worldwide. Most research has focused on establishing a causal link between innate immune activation and pathological inflammation leading to preterm labor and birth. However, the role of maternal effector/activated T cells in the pathogenesis of preterm labor/birth is poorly understood. In this study, we first demonstrated that effector memory and activated maternal T cells expressing granzyme B and perforin are enriched at the maternal-fetal interface (decidua) of women with spontaneous preterm labor. Next, using a murine model, we reported that prior to inducing preterm birth, in vivo T cell activation caused maternal hypothermia, bradycardia, systemic inflammation, cervical dilation, intra-amniotic inflammation, and fetal growth restriction, all of which are clinical signs associated with preterm labor. In vivo T cell activation also induced B cell cytokine responses, a proinflammatory macrophage polarization, and other inflammatory responses at the maternal-fetal interface and myometrium in the absence of an increased influx of neutrophils. Finally, we showed that treatment with progesterone can serve as a strategy to prevent preterm labor/birth and adverse neonatal outcomes by attenuating the proinflammatory responses at the maternal-fetal interface and cervix induced by T cell activation. Collectively, these findings provide mechanistic evidence showing that effector and activated T cells cause pathological inflammation at the maternal-fetal interface, in the mother, and in the fetus, inducing preterm labor and birth and adverse neonatal outcomes. Such adverse effects can be prevented by treatment with progesterone, a clinically approved strategy.

Mifepristone (RU 486) induces vasodilation and inhibits platelet aggregation: nongenomic and genomic action to cause hemorrhage

BACKGROUND

The regimen mifepristone/misoprostol is an established and highly effective method for early termination of pregnancy. However, its side effects such as a significantly long bleeding time and hemorrhage have been scantly studied.

STUDY DESIGN

Human umbilical artery (HUA) from pregnant women undergoing elective cesarean section at term and rat thoracic aorta (RTA) were isometrically recorded. The vasorelaxing effect of mifepristone was analyzed on the contractile responses induced by KCl or serotonin (5-HT); moreover, the potential response of mifepristone on adenosine diphosphate (ADP)-induced human platelet aggregation was also evaluated.

RESULTS

This study describes that mifepristone elicits (1) rapid and reversible vasorelaxation on KCl- or 5-HT-induced contraction in HUA and RTA with and without endothelium and (2) immediate prevention of ADP-induced human platelet aggregation.

CONCLUSIONS

These effects seem to be responsible for increased and prolonged hemorrhage. Since mifepristone-prevented platelet aggregation was observed in the anucleate platelets, and mifepristone-induced vasorelaxation remained unaffected in de-endothelized tissues, by inhibitors of transcription and translation and a nitric oxide (NO) synthase inhibitor, a nongenomic endothelium- and NO-independent mechanism was revealed. Additionally, the results indicated a blockade of voltage- and receptor-operated calcium channels. The antiglucocorticoid genomic action of mifepristone, by inducing an excess of NO, may also contribute to exacerbated hemorrhage.

Defining reality: the potential role of pharmacists in assessing the impact of progesterone receptor modulators and misoprostol in reproductive health

Medical abortion is increasingly heralded as an ideal method for decreasing maternal mortality in health-care resource-deprived areas and as an answer to the shrinking pool of physicians willing to perform abortions. The advent of progesterone receptor modulators (PRMs) and the recent approval by the Food and Drug Administration of ella (ulipristal) as an emergency contraceptive put pharmacists in the center of abortion controversy. Pharmacists, worldwide, need to be aware of the controversy surrounding the introduction of PRMs, particularly with regard to the effect on health policy, their mechanism of action, associated adverse events, and common off-label uses. Once understood, genuine opportunity exists for pharmacists to serve a fundamental role in positively shaping public health policy.

Current awareness: Pharmacoepidemiology and drug safety

In order to keep subscribers up‐to‐date with the latest developments in their field, John Wiley & Sons are providing a current awareness service in each issue of the journal. The bibliography contains newly published material in the field of pharmacoepidemiology and drug safety. Each bibliography is divided into 20 sections: 1 Reviews; 2 General; 3 Anti‐infective Agents; 4 Cardiovascular System Agents; 5 CNS Depressive Agents; 6 Non‐steroidal Anti‐inflammatory Agents; 7 CNS Agents; 8 Anti‐neoplastic Agents; 9 Haematological Agents; 10 Neuroregulator‐Blocking Agents; 11 Dermatological Agents; 12 Immunosuppressive Agents; 13 Autonomic Agents; 14 Respiratory System Agents; 15 Neuromuscular Agents; 16 Reproductive System Agents; 17 Gastrointestinal System Agents; 18 Anti‐inflammatory Agents ‐ Steroidal; 19 Teratogens/fetal exposure; 20 Others. Within each section, articles are listed in alphabetical order with respect to author. If, in the preceding period, no publications are located relevant to any one of these headings, that section will be omitted.