Evaluation of platelet function and lack of response to epinephrine in pregnant women

Abstract

Summary Previous studies in healthy subjects have demonstrated a lack of response of platelets to epinephrine at a rate of 16–40% on an aggregometer. An association between the increased procoagulant factors during pregnancy and venous thromboembolism is known, and it has also been shown that prolactin levels increase platelet aggregation. We evaluated whether platelet functions in pregnant women and also assessed the lack of response to epinephrine during this period. We compared 27 healthy and volunteering pregnant women with 26 similar control subjects. Platelet functions were assessed with an aggregometer and a Platelet Function Analyzer (PFA‐100). Less than 40% response to epinephrine on the aggregometer was defined as an impaired epinephrine response. The aggregation response of epinephrine was normal in 25 of the 27 pregnant women, while two of them showed a late‐rising response. Eight of the 26 subject control group (30.8%) showed an impaired response to epinephrine. When we compared the 25 pregnant and 18 control subjects with normal aggregation responses, the maximum aggregation responses to ADP and epinephrine, and the Col/Epi and Col/ADP cartridge closure time values were significantly lower in pregnant women. There were no difference beetween second and third trimesters as regards platelet function parameters. The fact that no impaired response to epinephrine was detected in pregnant women while a 30% rate was observed in non‐pregnant women indicates that the platelet malfunction caused by a disorder in the Gi protein and intracellular mechanisms is bypassed during pregnancy thanks to some physiological changes.

The Similarity Between Aspirin Treatment and the Lack of Response to Epinephrine and the Frequency of Aspirin Resistance in Healthy Males

“…Previous studies reported no relationship between the lack of response to Epi and age or gender. 2,6,8,9 Considering the distinguished military institution from which the participants were selected and the health controls routinely conducted in the institution, the fact that the lack of response to Epi was low make us think that there may be a relationship between a health parameter that we did not notice and the lack of response to Epi.…”

“…In addition, final Epi concentrations varied between 10 and 300 mmol/L. [2][3][4][5][6][7][8][9] The duration of the transition from primary aggregation to secondary aggregation for the Epi-induced aggregation response may show some interpersonal variations. It was indicated that in pregnant women the lack of response to Epi was not observed; this may be due to a late-rising response to Epi.…”

“…There are studies that demonstrate the resemblance of aspirin effects on platelets with the lack of response to Epi. [2][3][4][5][6][7][8][9] In the thrombus model generated using Col-Epi, the mortality rate was found to be significantly lower and thrombus formation in the lung sections was found to be significantly less in the G az knockout mice compared to the wild type. No difference was found for the Col-ADP model.…”

Impaired platelet function and peripartum bleeding in women with Gaucher disease

“…The association of impaired platelet function in pregnant Gaucher patients with an increased risk of peripartum bleeding has not been previously reported. On the contrary, Sagdilek et al (18) have demonstrated platelet function to be preserved in normal pregnancy when compared with non-pregnant controls, while other authors have shown platelet activation during specific pregnancy-related conditions such as preeclampsia (19,20) and pregnancy-induced hypertension (21).…”

“…Moreover, the reported results, obtained in a potentially hypercoagulable state, are applicable to future pregnancies only and should not be relied upon in cases of future surgical procedures in these patients. The lack of normal pregnancy controls for CPA studies is another flaw, yet since other studies have reported improved whole blood platelet function in pregnancy (18)(19)(20)(21), the use of normal population controls (whose whole blood platelet aggregation may be even lower than anticipated for normal pregnancy controls) as comparator for the Gaucher cohort, should not have affected our study's results and conclusion.…”