Are platelets elevated postpartum?

Platelet Counts in the Postpartum Period

Yes, platelet counts typically increase during the postpartum period, returning to pre-pregnancy levels after initially decreasing during pregnancy. 1

Normal Platelet Count Changes During Pregnancy and Postpartum

• During pregnancy, platelet counts progressively decrease, with a systematic review showing the following pattern 1:

  • First trimester: 251 × 10⁹/L (mean)
  • Second trimester: 238 × 10⁹/L (mean)
  • Third trimester: 224 × 10⁹/L (mean)
  • At delivery: 237 × 10⁹/L (mean)
  • Postpartum: 247 × 10⁹/L (mean)

• This pattern demonstrates a gradual decline during pregnancy that reaches its lowest point (nadir) at delivery, followed by a recovery postpartum 1.

• The decline in platelet count during pregnancy is attributed to several physiological mechanisms:

  • Increased plasma volume causing a dilution effect
  • Increased platelet sequestration in both splenic and placental circulation
  • Not due to blood loss 1, 2

Timing of Postpartum Platelet Recovery

• Platelet counts typically begin to recover immediately after delivery and continue rising during the postpartum period 1.

• Complete recovery to pre-pregnancy levels occurs approximately 7.1 weeks postpartum in normal pregnancies 1.

• In women with essential thrombocythemia (ET), platelet counts recover to 75% of baseline within 1 month postpartum 1.

Special Considerations: Preeclampsia and Postpartum Thrombocytosis

• In women with preeclampsia, a significant postpartum thrombocytosis can occur, with platelet counts increasing from a mean of 240×10⁹/L antepartum to 621×10⁹/L by days 6-14 postpartum 3.

• This increase is 2-3 times greater than in women with normotensive pregnancies, who show an increase from 214×10⁹/L antepartum to 351×10⁹/L by days 6-14 postpartum 3.

• The peak in platelet count typically occurs between 6-14 days postpartum, often after hospital discharge 3.

Clinical Implications

• Thrombotic Risk: The postpartum period carries a 4-6 fold increased risk of venous thromboembolism compared to pregnancy, with the greatest risk in the immediate postpartum phase 1.

• Hemorrhage Risk: Mild thrombocytopenia (100-149×10⁹/L) during delivery is associated with a twofold greater likelihood of postpartum hemorrhage compared to normal platelet counts 4, 5.

• Monitoring Considerations: When interpreting platelet counts postpartum, clinicians should be aware that:

  • A normal increase in platelets is expected postpartum
  • Failure of platelets to rise postpartum may indicate ongoing pathology
  • Excessive thrombocytosis, particularly in preeclamptic patients, may increase thrombotic risk 3

Practical Recommendations

• Monitor platelet counts postpartum, particularly in women with pregnancy complications such as preeclampsia or HELLP syndrome 6.

• Be aware that platelet counts below 40,000/μL intrapartum are most predictive of subsequent postpartum hemorrhagic complications 6.

• Consider that the hypercoagulable state of pregnancy persists through the first 24 hours postpartum, as reflected in thromboelastography (TEG) values 1.

• Recognize that the complete resolution of pregnancy-associated hypercoagulability takes approximately 4 weeks postpartum 1.