Article No. 454

 aHUS triggered by pregnancy is relatively common and accounts for 16% of female ( 18 to 45 years) aHUS incidents. 75% of the incidents occur post partum. One of top research subjects on the aHUS Patients Research Agenda is  “Do aHUS families have all the correct information to make informed family planning decisions?”

In one of the most comprehensive articles ( see full copy HERE) on the subject of TMA ( including aHUS) in pregnancy,  an International Working Group on Pregnancy-Related Thrombotic Microangiopathies provided a list of helpful elements for a patient with a history of aHUS who wishes to plan a pregnancy.

1. Pregnancy is no longer contraindicated in women with a history of aHUS.  The risk of relapse of aHUS during pregnancy or postpartum appears lower (∼25%) than formerly appreciated.  An efficient treatment (anti-C5 treatment such as eculizumab) is available.

2. The risk of relapse of aHUS triggered by pregnancy is difficult to predict.  A prior uneventful pregnancy does not guarantee subsequent pregnancies will be free of relapse.   Women who do not carry a complement gene variant are not protected from pregnancy aHUS.

  3. An interval of ∼12 months of aHUS remission and stabilized renal function is appropriate before pregnancy initiation.

4. In women with prior aHUS, relapse of aHUS occurs more frequently during pregnancy than after delivery.  In the pre-anti-C5 treatment era, this was associated with a high risk of fetal death or preterm birth. 

5. CKD may be a limitation to pregnancy.  Residual severe CKD or hypertension after aHUS may worsen during pregnancy, with increased risk of preeclampsia or HELLP syndrome, ESRD, and fetal death.

  6. In case of aHUS relapse, prompt anti-C5 treatment initiation optimizes chances of patient’s full recovery and child’s full-term live birth.

7. Prophylactic anti-C5 treatment is currently not recommended.  Anti-C5 treatment is usually not discontinued in women already treated prior to pregnancy (particularly renal transplant patients).

8. Pregnancy in a woman with a history of aHUS remains a high-risk pregnancy.  Close multidisciplinary (obstetricians, nephrologists, neonatologists, and complement biologists) supervision from the first weeks of pregnancy and up to 3 months  postdelivery in high-risk pregnancy maternity clinic is mandatory.

A short list of clear and simple information which can be used to discuss the decision with a patient’s own clinician before it is made.





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