What did the recent New England Journal of Medicine article teach us about the risk of a thrombotic event after the 6-week postpartum period? #503/14

Will this change the recommendation about starting combined oral contraceptive pills (COCs) postpartum?


“The postpartum state is associated with a substantially increased risk of thrombosis.  It is uncertain to what extent this heightened risk persists beyond the conventionally defined 6-week postpartum period.” [Kamal New England Journal of Medicine, April 3, 2014]

 

“Among the 1,687, 930 women with a first recorded delivery, 1015 had a thrombotic event (248 cases of stroke, 47 cases of myocardial infarction, and 720 cases of venous thromboembolism) in the period of 1 year plus up to 24 weeks after delivery.  The risk of primary thrombotic events was markedly higher within 6 weeks after delivery than in the same period 1 year later, with 411 events versus 38 events, for an absolute risk difference of 22.1 events (95% confidence interval {CI}, 19.6 to 24.6) per 100,000 deliveries and an odds ratio of 10.8 (95% CI, 7.8 to 15.1).  There was also a modest but significant increase in risk during the period of 7 to 12 weeks after delivery as compared with the same period 1 year later, with 95 versus 44 events, for an absolute risk difference of 3.0 events (95% CI, 1.6 to 4.5) per 100,000 deliveries and an odds ratio of 2.2 (95% CI, 1.5 to 3.1).  Risks of thrombotic events were not significantly increased beyond the first 12 weeks after delivery.”

           

“Among patients in our study, an elevated risk of thrombosis persisted until at least 12 weeks after delivery.  However, the absolute increase in risk beyond 6 weeks after delivery was low.”  (Funded by the National Institute of Neurological Disorders and Stroke).

 

The implications of this study are as follows:

Clinicians providing care to postpartum women may inform them that their risk of a thrombotic event is increased ten (10.8) fold in the first 6 weeks postpartum and by two fold (2.2) in weeks 7 to 12 postpartum.

 

The absolute increase in thrombotic events in weeks 7 to 12 is just 3.0/ 100,000 women.

 

For women considering using an estrogenic contraceptive “pills, patches or rings”, the CDC Medical Eligibility Criteria say that those estrogenic contraceptives represent an unacceptable health risk and should not be used by women in the first 3 weeks postpartum “CDC  MEC 4”

 

For women 21-42 days postpartum who have other risk factors for venous thromboembolism (VTE) estrogenic methods should NOT be used unless the clinician makes a clinical judgment that the patent can safely use it.  The theoretical or proven risks usually outweigh the advantages of the method. “CDC MEC 3”

 

For women 21-42 days postpartum without other risk factors for VTE combined hormonal contraceptives may be used and their advantages generally outweigh the critical or proven risks. “CDC 2”

 

 

US/CDC Medical Eligibility Criteria categories for temporary methods:

 

  • US/CDC MEC: 1 – Can use the method.  No restrictions on use.
  • US/CDC MEC: 2 – Can use the method.  Advantages generally outweigh theoretical or proven risks.  If method is chosen, more than usual follow-up may be needed.
  • US/CDC MEC: 3 – Should not use the method unless clinician makes clinical judgment that the patient can safely use it.  Theoretical or proven risks usually outweigh the advantages of method.  Method of last choice, for which regular monitoring may be needed.
  • US/CDC MEC: 4 – Should not use the method.  Conditions represents on unacceptable health risk if method is used.

 

 

To learn more about the advantages and disadvantages of all available contraceptive

methods; go to: www.managingcontraception.com and click on Choices 2013 edition.  You can also order this wonderful new educational book from our website or by calling 404-875-5001.  Do you have your copy yet?  It is now available in English and Spanish.   



Key Words:  postpartum, increased risk, thrombosis, stroke, myocardial infarction, delivery, study, elevated, National Institute of Neurological Disorders and Stroke

 

References:

Kamel H, Navi BB. IN Risk of a thrombotic event after the 6-week postpartum period et al: The New England Journal of Medicine: 370:14, April 3, 2014


Zieman M, Hatcher RA. CDC Medical Eligibility Criteria for appendix of managing Contraception. Starting contraceptive methods:  page A3, Skyla Edition 2013-2014

Posted 5-6-2014, Updated 6-2-2014, Updated 6-28-2014

Skills

Posted on

June 29, 2014