Aspirin

Aspirin does not prevent miscarriage in women with unexplained recurrent miscarriage

In this randomized trial, we enrolled 364 women between the ages of 18 and 42 years who had a history of unexplained recurrent miscarriage and were attempting to conceive or were less than 6 weeks pregnant. We then randomly assigned them to receive daily 80 mg of aspirin plus open-label subcutaneous nadroparin, 80 mg of aspirin alone, or placebo. The primary outcome measure was the live-birth rate. Secondary outcomes included rates of miscarriage, obstetrical complications, and maternal and fetal adverse events. RESULTS: Live-birth rates did not differ significantly among the three study groups. The proportions of women who gave birth to a live infant were 54.5% in the group receiving aspirin plus nadroparin (combination-therapy group), 50.8% in the aspirin-only group, and 57.0% in the placebo group. Among 299 women who became pregnant, the live-birth rates were 69.1% in the combination-therapy group, 61.6% in the aspirin-only group, and 67.0% in the placebo group. CONCLUSIONS: Neither aspirin combined with nadroparin nor aspirin alone improved the live-birth rate, as compared with placebo, among women with unexplained recurrent miscarriage.

http://www.ncbi.nlm.nih.gov/pubmed/20335572

Aspirin does not prevent miscarriage in women without thrombophilia

Two studies (189 participants) were included in the review. In one study, 54 pregnant women with recurrent miscarriage but no detectable anticardiolipin antibodies were randomised to low-dose aspirin or placebo. Recurrent miscarriage was defined as three or more consecutive miscarriages (occurring before 22 weeks' gestational age). Similar live-birth rates were observed with aspirin and placebo, both 81%. In the other study, 107 women with consecutive recurrent miscarriage without any apparent cause and no hereditary thrombophilia were randomised between enoxaparin and aspirin. Here recurrent miscarriage was stated as three or more consecutive first trimester miscarriages or at least two consecutive second trimester miscarriages. Similar live birth rates were observed with enoxaparin and aspirin, respectively 82% and 84%.

http://www.ncbi.nlm.nih.gov/pubmed/19160241

Aspirin reduces the chances of a recurrent loss after 10 weeks by 59%

Subjects were identified from patients referred for evaluation of fetal death (occurring at >/= 10 weeks of gestation) and having at least one subsequent pregnancy. Patients with antiphospholipid antibodies were excluded. RESULTS: Older age at pregnancy (odds ratio 0.63) and treatment with low-dose aspirin (odds ratio 0.41) to be associated with a decreased risk for subsequent pregnancy loss.

http://www.ncbi.nlm.nih.gov/pubmed/15339762

Women with unexplained recurrent miscarriage have increased blood clotting

We conducted a prospective study comparing 30 patients with unexplained recurrent first-trimester miscarriage with 30 control subjects matched for age and serum progesterone level. Platelet function was determined. RESULTS: At test completion the half-maximal effective concentration values for arachidonic acid in the patients with recurrent miscarriage were significantly less than in the control subjects (0.153 vs 0.230). The dose-response curves were tightly matched for the other agonists. CONCLUSION: This novel measurement of platelet function has demonstrated that patients with unexplained recurrent miscarriage have significantly increased platelet aggregation in response to arachidonic acid. The enhanced response to this agonist provides an empirical rationale for the use of aspirin in management of this clinical condition.

http://www.ncbi.nlm.nih.gov/pubmed/20684942

Aspirin does not improve implantation rate and reduces follicle growth

We performed a randomized analysis of 145 infertile women with a mean age of 29.6 years who underwent cycles of IVF. Patients received 100 mg of aspirin or placebo daily. Aspirin was started on the 21st of their preceding menstrual cycle and it was continued until menstruation or a negative pregnancy test. Pregnant women received the medication until 12 weeks of pregnancy. The main outcome measures were number of follicles >or=15 mm, number of oocytes retrieved, serum estrogen levels, cancellation rate, Ovarian Hyperstimulation Syndrome (OHSS) occurrence, number of embryos transferred, and implantation and pregnancy rates. RESULTS: There were statistically significant differences between the treatment group and the control group in the number of follicles (7.4 versus 9.0) and OHSS occurrence (5.6% versus 23.3%) but not in the other measures. CONCLUSION: The addition of aspirin low dose (100 mg/daily) to the standard long protocol for oocyte retrieval did not improve implantation and pregnancy rates in unselected patients undergoing IVF cycles.

http://www.ncbi.nlm.nih.gov/pubmed/17457441

Aspirin lowers hematocrit

Hematocrit (which is high in women with first trimester growth restriction), fibrinogen, plasma and whole blood viscosity were significantly higher in patients with diabetic retinopathy who did not take aspirin than in those who took. No significant difference was observed in red blood cell aggregation parameters between the two groups.

http://iospress.metapress.com/content/j365t847k338l273/

Aspirin prevents intrauterine growth restriction

Early aspirin treatment reduces the incidence of intrauterine growth restriction in a high-risk population but should not be used routinely in all pregnant women.

http://www.ncbi.nlm.nih.gov/pubmed/9730666

Aspirin may interfere with implantation and cause certain birth defects

In theory, aspirin has both positive and negative effects on reproduction. Aspirin, which suppresses cyclooxygenase, has the potential to interfere with implantation, but also has the potential to support the maintenance of pregnancy. Aspirin is prescribed with increasing frequency to reduce the risk of maternal thrombosis and reduce the risk of miscarriage and poor pregnancy outcome. Aspirin alone, however, is not considered sufficient to prevent thrombosis and even in women with the antiphospholipid syndrome, the question as to whether low-dose aspirin improves pregnancy outcomes has not been answered affirmatively. Aspirin has potential risks. Aspirin inhibits platelet function and can contribute to maternal and fetal bleeding. Aspirin crosses the placenta. Although aspirin has not been associated with other congenital anomalies, it has been associated with an increased risk of vascular disruptions, particularly gastroschisis and possibly premature closure of the ductus arteriosus. Nonetheless, large trials demonstrate low-dose aspirin's relative safety and generally positive effects on reproductive outcomes.

http://www.ncbi.nlm.nih.gov/pubmed/18081940

Aspirin blocks the masculinization of male embryos

The masculinization of male embryos is inhibited by indomethacin and aspirin, and the masculinization of female embryos produced by exogenous testosterone is prevented by indomethacin.

http://www.ncbi.nlm.nih.gov/pubmed/3086881

Buffered aspirin causes less birth defects than regular aspirin

Aspirin (acetylsalicyclic acid) was dissolved either in normal saline or in phosphate buffer and was used in two doses to find out whether teratogenic potential of aspirin in chick blastoderm model is due to its acidic property or due to drug action. Normal development of embryos was seen with normal saline and percentage of normal embryos with 30 micrograms (pH-3.19) and 120 micrograms (pH-2.64) aspirin was 31.7% and 4.9% respectively. Buffer produced 80.8% normal embryos and buffered 30 micrograms (pH-6.87) and 120 micrograms (pH-6.69) aspirin produced 67.7% and 30.8% normal embryos respectively. Changing the pH of aspirin to near neutral decreased the defect induced by aspirin but a significant effect of aspirin was observed at higher dose which could be independent of pH action.

http://www.ncbi.nlm.nih.gov/pubmed/7649600