Obstetrics د.ايناس الخياط Autoimmune disease in pregnancy
An autoimmune disease is one in which antibodies are developed against the host's own tissue .
I Autoimmune thrombocytopenic purpura ( ITP ) :
Autoimmune antibodies are produced against platelet surface antigens , leading to platelet destruction by reticulo-endothelial system .
- The incidence in pregnancy is 1 : 5000 .
- In pregnancy ; the condition may present with bruising or be suspected for the first time following a routine blood count .
- The count is typically 30 80 x 109 / L .
- Other associated autoimmune conditions should be considered , including SLE & APS .
Differential diagnosis :
1. Gestational thrombocytopenia :
Is a benign symptomless condition , no risk of bleeding , No fetal effect , and no treatment is required .
It occur late in pregnancy , platelet count unlikely < 70,000 ml and resolution within 6 wks after delivery .
2. Hypertensive disorder of pregnancy .
3. Others ( DIC , HELLP , acute fatty liver , thrombotic , thrombocytopenia ) .
So the diagnosis is after exclusion of other causes of ITP .
Management :
- Serial platelet counts , provided the count remains above 80x 109/L , no bleeding complications , regional epidural- spinal anesthesia and analgesia may be used .- If platelet count < 50 x 109 / L approaching term , treatment should be considered by :
1. corticosteroids : act by suppressing autoantibodies , however , high doses are often required , and long-term use is associated with weight again , hypertension , diabetes and osteoporosis . Also it takes 2 3 weeks to have an effect .
2. Intravenous immunoglobulin G ( IgG ) : prolongs the clearance times of IgG coated platelets by reticuto- endothelial system .
- The response is usually rapid & length of effect of 2 3 weeks .
- Because of cost implication , this treatment is usually reserved for cases that dont respond to steroids , or when a rapid response is required prior to delivery , or if there's bleeding in the postpartum period .
3. Final treatment : is splenectomy , but this is very rarely undertaken in pregnancy as it is associated with significant maternal and prenatal mortality .
4. Platelet transfusion : used only in acute situation ( to deal with haemorrhage or to cover delivery ) .
- In pregnancy , these antibodies may cross the placenta and destroy the fetal platelets . in < 5% of fetuses of women with ITP .
So : 1) traumatic delivery should be avoided .
2) Platelet count of the neonate should be monitored .
II Systemic lupus erythematosus ( SLE ) and
antiphospholipid syndrome ( APS )
- SLE : is a multi-system chronic autoimmune inflammatory disease .
- It is 5 10 times more common in women , particularly in black and Asian populations .
- It may cause disease in any system , but principally it affects the joints , kidneys, lungs , nervous system , and heart .
- Presentation & diagnosis :
-SLE may be diagnosed prenatally or may be suspected for the first time during pregnancy or the postpartum period , usually as a result of complications .- SLE is a relapsing condition , and pregnancy increases the risk of flare.
- Approximately 1/3 of mothers with SLE will experience an exacerbation during pregnancy and 1/3 of them unchanged and 1/3 of them will be improved during the pregnancy.
- Lupus flare can be life threatening but it is difficult to differentiate lupus flare from superimposed pre-eclampsia .
Diagnosis :
By presenting > 4 of the 11 revised criteria of American Rheumatism Association , are present serially or simultaneously .
- By finding of a positive assay for antinuclear antibodies , and the presence of antibodies to double-stranded DNA is the most specific for SLE and anti Ro and anti La .
Antiphospholipid syndrome ( APS ) :
Is used to describe the association of :anticardiolipin antibodies and / or lupus anticoagulant .
with typical clinical features of arterial or venous thrombosis .
Fetal loss after 10 wks gestation or delivery before 34 wks due to IUGR or pre-eclampsia .
> 3 miscarriages at less than 10 week's gestation .
APS may be primary or found in association with SLE .
Maternal and fetal risk of SLE and APS
Maternal :
- Lupus flare .
- worsening nephropathy , proteinuria .
- Thrombosis DVT , or even in unusual site ex. retinal vein .
- Thrombocytopenia .
- Placenta abruption .
Fetal :
- Miscarriage .- Fetal death .
- Growth restriction ( IUGR ).
- Preterm labour .
- Neonatal lupus due to transplacental passage of anti Ro/ anti .
- Congenital heart block 1 2 % of babies of Ro-positive female .
Management of SLE and APS :
Because of these significant risks , pregnant women with SLE and APS require intensive monitoring for both maternal and fetal indications .- The mother should be seen frequently and baseline renal studies , including a 24 hrs urine collection for protein , should be performed .
- The blood pressure should be monitored closely because of the increased risk of pre-eclampsia .
- Serial U/S is performed to assess fetal growth .
- If antenatal treatment is required for SLE; steroids and azathioprine may be given safely .
- NSAIDS should be avoided in pregnancy because of adverse effects on the fetus .
- If the patient on warfarin , when become pregnant change to Aspirin &low molicular heparin (LMW Heparin) as soon as pregnancy is confirmed through out the pregnancy & postpartum period ( 6 wks ) .
- In women with APS who have suffered repeated pregnancy loss or sever obstetric complications , the use of aspirin + heparin has been shown to reduce the pregnancy loss rate (with pregnancy sucsess rate 70%) .
III Rheumatoid arthritis ( RA ) :
Chronic inflammatory , symmetrical arthritis causing joint pain , stiffness & deformity .
30 % antinuclear antibody + ve
20 30 % Anti Ro / anti La + ve
5 10 % A PL + ve
3/4 of them experience improvement of symptoms during pregnancy .
R.A. has no adverse effect on pregnancy outcome, but the adverse effects may be due to treatment of the disease or passing abnormal antibodies through the placenta .
Treatment :
1. Paracetamol : safe , can be used in maximum dose .2. NSADs avoided in pregnancy effect on fetal kidneys
oligohydramios & premature closure of ductus arterosus pulmonary hypertension .
3. corticosteroids : relatively safe
But large dose infection , gestational diabetes and premature rupture of membrane and fetal adrenal suppression .
4. Azathioprine : also safe
5. Gold and pencillamine avoided in pregnancy .
6. Cytotoxic agent teratogenic & should be discontinued before
pregnancy .
OBJECTIVE
The students should know about :
Definition of autoimune disease .
How can be dignosed during pregnancy .
The effect of autoimune disease on the pregnancy outcome.
The effect of pregnancy on the disease' s course .