Antiphospholipid syndrome and recurrent miscarriage

Question 1

Adverse pregnancy outcome and APS

Answer 1

• Three or more consecutive miscarriages before 10 weeks of gestation
• One or more morphologically normal fetal losses after the 10th week of gestation
• One or more preterm births before the 34th week of gestation owing to placental disease.

Question 2

Mechanisms of recurrent miscarriage in APS

Answer 2

• Inhibition of trophoblastic function and differentiation
• Activation of complement pathways at the maternal–fetal interface resulting in a local inflammatory response
• Later pregnancy thrombosis of the uteroplacental vasculature
• All reversed by heparin

Question 3

Levels of APS diagnostic

Answer 3

• IgM medium or high titre over 40 g/l or ml/l, or above the 99th percentile
• Dilute Russell’s viper venom time test together with a platelet neutralisation procedure is more sensitive and specific than either the activated partial thromboplastin time test or the kaolin clotting time test