Prostanoid excretion in incipient singleton and twin pregnancies

Antithrombotic Treatment for Recurrent Miscarriage: Bayesian Network Meta-Analysis and Systematic Review

Combined use of heparin and aspirin is frequently prescribed for treatment of recurrent miscarriage (RM) in patients with antiphospholipid syndrome (APS), or in those without apparent cause of RM other than thrombophilia; however, this strategy is largely based on expert opinion and has not been well studied. The option for the use of different antithrombotic therapies to improve live birth remains unclear. In this network meta-analysis, we incorporated direct and indirect evidence to evaluate effects of different antithrombotic treatments on prevention of pregnancy losses.We searched PubMed and Embase for randomized clinical trials comparing effects of at least 2 antithrombotic treatments on live birth in RM patients published from 1965 through the early of May 2015. Potential risk bias of eligible trials was evaluated according to the Cochrane Collaboration guidelines. Bayesian network meta-analysis was used to estimate relative effects on live birth.A total of 19 trials involving 2391 RM patients with or without thrombophilia and 543 with APS were included. No beneficial effect of antithrombotic treatment was observed either in RM patients with or without thrombophilia or in patients with APS; however, for patients with or without thrombophilia, low molecular weight heparin therapy had the greatest probability (61.48%) of being the best option in terms of live birth; for patients with APS, unfractionated heparin plus aspirin was the superior treatment for RM with the highest possibility (75.15%) of being top 2 places for reducing pregnancy losses. Aspirin was inferior in both groups.Our results do not support the use of combined low molecular weight heparin and aspirin for RM treatment, and suggested aspirin may have negative effects for lowering the risk of pregnancy loss.

Endothelium-dependent relaxation and angiotensin II sensitivity in experimental preeclampsia

Objective

We investigated endothelial dysfunction and the role of angiotensin (Ang)-II type I (AT1-R) and type II (AT2-R) receptor in the changes in the Ang-II sensitivity in experimental preeclampsia in the rat.

Methods

Aortic rings were isolated from low dose lipopolysaccharide (LPS) infused pregnant rats (experimental preeclampsia; n=9), saline-infused pregnant rats (n=8), and saline (n=8) and LPS (n=8) infused non-pregnant rats. Endothelium-dependent acetylcholine--mediated relaxation was studied in phenylephrine-preconstricted aortic rings in the presence of vehicle, N^G-nitro-L-arginine methyl ester and/or indomethacin. To evaluate the role for AT1-R and AT2-R in Ang-II sensitivity, full concentration response curves were obtained for Ang-II in the presence of losartan or PD123319. mRNA expression of the AT1-R and AT2-R, eNOS and iNOS, COX1 and COX2 in aorta were evaluated using real-time RT-PCR.

Results

The role of vasodilator prostaglandins in the aorta was increased and the role of endothelium-derived hyperpolarizing factor and response of the AT1-R and AT2-R to Ang-II was decreased in pregnant saline infused rats as compared with non-pregnant rats. These changes were not observed during preeclampsia.

Conclusion

Pregnancy induced adaptations in endothelial function, which were not observed in the rat model for preeclampsia. This role of lack of pregnancy induced endothelial adaptation in the pathophysiology of experimental preeclampsia needs further investigation.

Exposure to non-steroidal anti-inflammatory drugs during pregnancy and risk of miscarriage: population based cohort study

OBJECTIVE

To evaluate whether prenatal use of non-steroidal anti-inflammatory drugs (NSAIDs) is associated with increased risk of miscarriage.

DESIGN

Population based cohort study. Prenatal use of NSAIDs, aspirin, and paracetamol (acetaminophen) ascertained by in-person interview.

SETTING

Kaiser Permanente Medical Care Program, a healthcare delivery system, in the San Francisco area of the United States.

PARTICIPANTS

1055 pregnant women recruited and interviewed immediately after their positive pregnancy test. Median gestational age at entry to the study was 40 days.

MAIN OUTCOME MEASURES

Pregnancy outcomes up to 20 weeks of gestation.

RESULTS

53 women (5%) reported prenatal NSAID use around conception or during pregnancy. After adjustment for potential confounders, prenatal NSAID use was associated with an 80% increased risk of miscarriage (adjusted hazard ratio 1.8 (95% confidence interval 1.0 to 3.2)). The association was stronger if the initial NSAID use was around the time of conception or if NSAID use lasted more than a week. Prenatal aspirin use was similarly associated with an increased risk of miscarriage. However, prenatal use of paracetamol, pharmacologically different from NSAIDs and aspirin, was not associated with increased risk of miscarriage regardless of timing and duration of use.

CONCLUSION

Prenatal use of NSAIDs and aspirin increased the risk of miscarriage. These findings need confirmation in studies designed specifically to examine the apparent association.

Urinary prostaglandin excretion in pregnancy: the effect of dietary sodium restriction

INTRODUCTION

Dietary sodium restriction results in activation of the renin-angiotensin-aldosterone-system. In the non-pregnant situation renin release in response to a low sodium diet is mediated by prostaglandins. We studied the effect of dietary sodium restriction on urinary prostaglandin metabolism in pregnancy.

PATIENTS AND METHODS

In a randomized, longitudinal study the excretion of urinary metabolites of prostacyclin (6-keto-PGF(1 alpha)and 2,3-dinor-6-keto-PGF(1 alpha)) and thromboxane A(2)(TxB(2)and 2,3-dinor-TxB(2)) was determined throughout pregnancy and post partum in 12 women on a low sodium diet and in 12 controls.

RESULTS

In pregnancy the excretion of all urinary prostaglandins is increased. The 6-keto-PGF(1 alpha)/ TxB(2)-ratio as well as the 2, 3-dinor-6-keto-PGF(1 alpha)/ 2,3-dinor-TxB(2)-ratio did not significantly change in pregnancy. CONCLUISION Prostacyclin and thromboxane do not seem to play an important role in sodium balance during pregnancy.

Which prostanoid metabolites should be determined for the study of reproductive processes?

The non-enzymatic metabolites of prostacyclin (PGI2) and thromboxane A2 (TXA2), 6-keto-prostaglandin F1alpha (6-keto-PGF1alpha) and thromboxane B2 (TXB2), and their 2,3-dinor metabolites, 2,3-dinor-6-keto-PGF1alpha and 2,3-dinor-TXB2, were measured in early morning urine samples in 24 in vitro fertilization (IVF) cycles in 24 women and in 27 women who became pregnant after IVF and embryo transfer (ET). The sum of the non-enzymatic metabolites and their 2,3-dinor metabolites was considered to be a reflection of total PGI2 and total TXA2 production in vivo. Both the ratio of 'total' PGI2/'total' TXA2 and the ratio of the 2,3-dinor metabolites were calculated. TXB2 concentrations showed virtually no change and the ratios of the non-enzymatic metabolites of PGI2 and TXA2 versus their 2,3-dinor metabolites remained relatively constant. As a consequence, the ratio of 2,3-dinor-6-keto-PGF1alpha/2,3-dinor-TXB2 was a close reflection of the ratio of 'total' PGI2/'total' TXA2, although the latter ratio was significantly higher all the time. We conclude that for comparative studies on the balance between PGI2 and TXA2 in IVF cycles and during gestation, the determination of the 2,3-dinor metabolites alone can replace the measurement of all four metabolites.

Do prostacyclin and thromboxane contribute to the "protective effect" of pregnancies with chronic hypertension? A preliminary prospective longitudinal study

OBJECTIVE

The aim of this study was to assess prospectively the urinary excretion of renal and systemic metabolites of thromboxane and prostacyclin in normotensive and chronic hypertensive pregnancies.

STUDY DESIGN

Pregnant hospital employees were invited to collect 24-hour urine samples weekly from the seventh week until delivery. Concentrations of renal metabolites (thromboxane B2, 6-keto-prostaglandin F1alpha) were measured by radioimmunoassay after extraction. Systemic metabolites (2,3-dinor-thromboxane B2, 2,3-dinor-6-keto-prostaglandin F1alpha) were assessed by enzyme immunoassay after extraction and high-pressure liquid chromatographic separation.

RESULTS

Thromboxane B2 excretion was similar in normotensive and hypertensive pregnancies, whereas a twofold increase of 6-keto-prostaglandin F1alpha was observed in hypertensive compared with normotensive pregnancies (7537 +/- 349 vs 3857 +/- 202 pg/mg creatinine, p < 0.001). During pregnancy in both conditions measurements displayed uniform excretion of thromboxane B2 with progressively increased levels of 6-keto-prostaglandin F1alpha in chronic hypertension (R2 = 0.60, p < 0.005). Mean excretion of 2,3-dinor-thromboxane B2 averaged 1208 +/- 65 and 898 +/- 48 pg/mg creatinine in normotensive and hypertensive pregnancies (p < 0.001), mainly due to significant decreased concentrations in hypertension in the first half of pregnancy. Conversely, 2,3-dinor-6-keto-prostaglandin F1alpha levels were 845 +/- 39 and 1226 +/- 67 pg/mg creatinine in normotensive and hypertensive pregnancies (p < 0.001), mostly because of significantly increased production in hypertension from 22 weeks onward. Ratios of both renal and systemic metabolites favored increased prostacyclin production in chronic hypertension.

CONCLUSION

In contrast to preeclampsia, uncomplicated mild to moderate chronic hypertensive pregnancies are characterized by an excess production of prostacyclin with unaltered or even lower thromboxane concentrations, which may contribute to the general favorable outcome of this hypertensive condition.