02/04 Aspirin and Calcium Use in Pregnancy

Overview of Aspirin and Calcium in Pregnancy

• Purpose of Discussion:

  • Focus on the use of aspirin and calcium in preventing pregnancy complications such as preeclampsia and growth restrictions in babies.

• Aspirin Use in Pregnancy:

  • Low dose aspirin (LDA) has been identified as beneficial particularly for women at high risk of preeclampsia.

  • Effective for women with a history of growth-restricted babies or those experiencing placental insufficiency.

  • Research supports the significant clinical reduction in preeclampsia risk from low doses of aspirin, especially in at-risk populations.

  • Wonder drug status is limited to specific at-risk cases rather than general use among all pregnant women.

• Mechanism of Action of Aspirin:

  • Prevents preeclampsia primarily by inhibiting thromboxane A2, a vasoconstrictor, while promoting the uptake of nitric oxide in the endothelium.

  • Enhances endothelial function by increasing nitric oxide availability, which aids in vasodilation and has anti-inflammatory properties.

  • Reduces platelet aggregation, thereby exerting antithrombotic effects.

• Efficacy and Recommendations:

  • Cochrane Review (Dooley et al. 2007):

  • Found aspirin reduced the risk of preeclampsia by 17%.

  • Associated with a decrease in preterm birth (8%), small for gestational age (SGA) babies (13%), and perinatal deaths (14%).

• Dosage and Administration:

  • Recommended dose: 100 mg per day, suggested to be taken at night for optimal blood pressure control.

  • Initiation of aspirin should occur between 12-16 weeks of gestation; use prior to 12 weeks is not universally recommended.

  • Discontinue aspirin around 36 weeks, although research is ongoing regarding safety of continued use until birth.

• Calcium's Role in Pregnancy:

  • Vital for vascular health, aiding in blood pressure regulation.

  • Insufficient calcium intake is linked to gestational hypertension, preeclampsia, and fetal growth restrictions.

  • Recommended dietary intake is often insufficient during pregnancy due to dietary challenges.

• Calcium Supplementation:

  • Cochrane meta-analysis (Hofmeyr, 2014):

  • Suggested daily supplementation of more than 1000 mg in the second trimester can lead to a 55% reduction in preeclampsia risk.

  • Recommended calcium intake for high-risk women: 1.5 to 2 g per day.

  • Synergistic effect with vitamin D for proper function; both need to be present for optimal efficacy.

• Dietary Considerations:

  • Calcium-rich foods may be expensive and harder to access; dietary evaluation is essential in early assessments.

  • For those unable to meet dietary requirements, supplementation is crucial, generally starting from 12 weeks of gestation alongside aspirin.

• Conclusion:

  • Strategies for managing pregnancy risk include assessing dietary intake of calcium and the implementation of low-dose aspirin for at-risk women.

  • Collaboration with obstetricians is necessary for prescribing both medications, with risk assessments triggering timely referrals for specialist discussions.

  • Ongoing research will continue to inform guidelines about the use of aspirin and calcium, with potential adjustments to recommendations based on evolving evidence.

• Physiopathology Recap:

  • Low-dose aspirin is paramount in the management of pregnant women at risk for complications such as preeclampsia and growth restrictions.

  • The mechanisms through which aspirin operates include the inhibition of thromboxane A2 and improving nitric oxide availability, which is crucial for endothelial health and managing blood pressure.

• Aspirin Administration:

  • To achieve optimal benefits, aspirin should ideally be commenced prior to 16 weeks of gestation.

  • The recommended dosage is 100 mg per day, preferably taken at night to aid in blood pressure regulation, with initiation between 12-16 weeks of gestation.

  • Aspirin use should be reassessed and potentially discontinued around 36 weeks, although ongoing research is evaluating the safety of continued use until birth.

• Calcium's Role:

  • Calcium plays a vital role in vascular health and is essential for proper blood pressure regulation during pregnancy.

  • Calcium supplementation, particularly starting at booking, is crucial to avoid insufficiencies that can lead to gestational hypertension and preeclampsia.

• Recommendation:

  • High-risk women should aim for a calcium intake of 1.5 to 2 g per day to mitigate risks associated with pregnancy complications.