Asthma in Pregancy

Many a senior obstetricians have expressed concern by quoting that asthma is the   commonest chronic   medical illness to complicate   pregnancy, affecting up to  5-12%   of women of childbearing age. It is    often undiagnosed( due to lack of routine checkup)  and therefore often  may be undertreated  .The responsibility bestows on us  as pregnancy  provides an   opportunity   to  pick up new cases of asthma  (diagnosis of    asthma)  and to optimize   the treatment   of women   already known   to have asthma.

Clinical features: The commonest symp is dry cough.  This is followed by breathlessness (SOB= shortness of breath particularly in walking staircase –going to roof for domestic purposes) . 3)  Wheezy   breathing on auscultation. Symptoms are commonly worse   at night and in the early morning . There    may be some definite  clear provoking  trigger factors such as Pollen , pet dogs, cat,(Animal  dander  ) etc. Signs of B asthma   are often absent unless seen during an acute attack . Therefore some cases may be missed in first ANC vests and many women dont disclose more so if in-law is present  and accompany   her. As such many early preg cases with mild to moderate cases are missed. Another drawback of  ours is  though most physicians keep a pulse oximetry at their clinics obstetricians don’t .In acute stage however, we the obstetricians can diagnose  by  watching her a tendency to frequent  cough ,inability to complete sentence and observing  increased respiratory rate .Wheeze be heard at ANC visits , and as we can auscultate chest we can listen to rhonchus  . Bronchoconstriction is often intermittent and caused    by the following  smooth  muscle spam   in the airway       walls backed up by b) Inflammation with swelling  and excessive production of mucus . A hallmark of asthma    is variability and reversibility of the bronchoconstriction

How to confirm the diagnosis of B asthma?? At a specialized clinic (Resp Medicine specialists)  by spirometry the degree of bronchoconstriction can be  measured with  a PEFR or more preferably spirometry(TFT)  which  measures       FEV  and forced vital capacity  .Where     the history    suggests a high probability of asthma or the FEV   / FVC  ratio is  <0.7   a trial of  treatment is indicated.

When does SOB (shortness of breath ) exacerbate??  Ans;-A typical    feature is morning dipping in the peak   flow.  In fact a > 20 %   diurnal variation   in PEFR  for 3 or more days a week during    a 2 week PEFR diary   is diagnostic. During the first day spirometry (TFT) most of pulmologist often ask on report of FEV(forced exp volume) after administering  a B  sympathomimmetic bronchodilator to confirm nature & degree of reversibility. If there is greater    than 15%   improvement    in FEV   following    inhalation of a B  sympathomimmetic bronchodilator(salbutamol)  then the inference is B asthma. Another test which is not so commonly done is degree of fall in % of  FEV  following    6 minutes of exercise . This  degree of fall indicates  a asthma.

 

Not to stop Asthma medication in pregancy :What may be effects of  pregnancy on asthma: Asthma may improve, deteriorate or remain unchanged during pregnancy .A) Women   with only mild disease   are unlikely to experience problems.  B) But those    with severe asthma are at greater risk of deterioration particularly    late in pregnancy. But we as caregivers should remember that women whose symptoms    improve during the last    trimester of pregnancy may experience postnatal   deterioration. It is like thyroid storm or say  Postpartum thyroiditis

 Deterioration in disease control is commonly caused by reduction or even    complete cessation of medication   due to fears about its safety. Home      peak    flow monitoring and written   personalized self management plans   should be encouraged.

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-        Drugs for   asthma in Pregancy :- The treatment    of asthma   in preganncy is essentially no different    from the treatment of   asthma including systemic steroids are safe    in pregancy and during   lactation.

-       The challenge in the management   of pregnant women   with asthma  is to ensure adequate  pre conception     or early  pregnancy   counseling    so  that women do nt stop  important  anti inflammatory inhaled  therapy .At the first vist after the diag is made about asthma by a pulmologist after Spirometry the pregnant women   should be advised that  their asthma is unlikely to adversely affect  their  pregnancy    and almost all drugs are safe , The benefit of drugs (mainly inhalers)  outweigh any risk to foetus . Moreover, maintaining good control of asthma throughout pregnancy      may   minimize    any added small risks. Another duty bestow on us .It is we,  who should always advice that      in the management   of asthma  it  is  the prevention    rather than the treatment is of paramount importance .All kinds of acute    attacks must be prevented by regular inhalers as prescribed by the pulmologist . The     aim of treatment is to achieve   virtual total freedom   from symptoms   such that the lifestyle of the individual is not affected.  Regrettably many women both I pregnancy period and at breast feeding time , they  accept   asthma as a common incurable diseases.   However, chronic  symptoms   such as wheezing or chest tightness on waking as an inevitable consequence of their disease  . This is    inappropriate and pregnancy provides    an ideal   opportunity to counsel such women    with asthma .:

1) Women    should be advised to stop smoking 2) No pets & regular  cleaning of bed sheets/ linens/avoid carpets/ cleansing  of house dusts/Care of mites /avoid pollens. Foods if she  has allergy. Explanation   and reassurance   regarding  the importance   and safety  of regular medication in pregnancy    is essential   to ensure  compliance.  Women with asthma should be encouraged to avoid known trigger factors

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How do we know that there is   complete control   of asthma?? Ans:- complete control   is defined as the absence    of 1) daytime symptoms 2)    night time awakening due to asthma 3) no  need for rescue medication   for  exacerbations  4) no limitation  on   activity   including exercise and  at clinic visits 5) normal FEV  or PEFR> 80 %  predicted.

It is   important     to check the woman’s   inhaler technique since failure to do this   may result in unnecessary escalation of therapy some women require    a breath actuated inhaler.

Mild     intermittent asthma is managed with inhaled short acting reliever   medication as required.

If usage   of a reliever inhaler exceeds three times per week regular inhaled anti inflammatory medication    with a steroid preventer inhaler   should be commenced

·    A) Short acting B agonist (salbutamol) : Brand name: LEVOLIN Inhaler (levo salbutamol). Such is B2   agonists if administered orally  then  via  the systemic circulation  salbutamol ingested  cross the placenta rapidly but very little of a given   inhaled dose      reaches the lungs and only a minute fraction of this   reaches   the systemic circulation  from inhaled Levo salbutamol

-       B) long acting    reliever    B  agonist    e.g.  salmenterol :These LABA=long acting Beta agonists . SALMETROL IS VAILABLE AS SEROBID. Brand TIOVA( Tiotropium Bromide) .Such are   salmenterol are  safe   in  pregnancy.  They   should not be discontinued    or withheld in those who require   them  for good asthma control

C) Steroid inhaler :- Use of both  inhaled and oral steroids is safe   in pregnancy . Only minimal amounts of inhaled corticosteroid preparations are systemically   absorbed.  Use of     a large   volume  spacer may improve   drug delivery and   is recommended   with  high doses of inhaled    steroid dosage   and if appropriate   given an emergency     supply of oral steroids .

-       There is no    evidence for an increased   incidence of   congenital   malformations or adverse fetal   effects   attributable to the use of inhaled beclomethasone or budesonide. Fluticasone propionate    is a longer acting   inhaled  corticosteroid  that may be  used for    used     for those requiring high   doses of   inhaled steroids

D)  Leukotriene receptor antagonist:-

E) Combination inhalers  of corticosteroids  plus  LABA for example  budesonide / for  moterol  and fluticasone / salmeterol  are widely   available     and may aid    compliance. One such example is Foracort which contains FORMOTTEROL & Budesonide .And another is Seroflow ( Salmeterol & Fluticasone) –Copal.  They also ensure   that the LABA is not taken    without inhaled  steroid   although   to increase   the dose   of inhaled   steroid   without   exceeding  the maximum    dose  of  LABA may   necessitate changing  the strength   of the inhaler    rather than asking    the patient   to take more puffs.

Steroids with short acting b agonists: These are Aerocort( Beclomethasone & salbutamol). AEROCRT SPRAY.

E)  Slow release   oral Theophylline

F) Oral B   agonist if fails   to achieve adequate    control by inhaler then salbutamol Tab(Asthalin, Salbetol, , Ventrolin   etc)  

G) Continuous   or frequent use   of oral    steroids becomes necessary. The lowest dose providing adequate    control should be used if necessary   with  steroid  sparing   agents . Prednisolone is   metabolized  by the placenta and very   little   active drug   reaches   the fetus. Although some   workers    have found   an increased incidence of   cleft palate with   first trimester    exposure    to steroids  this finding    is refuted in larger prospective case-   control   and database    linkage    studies. There is no evidence   of an    increased risk    of miscarriage. Stillbirth   other congenital   malformations or neonatal death  attributable to maternal    steroid therapy. There   is a non significant   increase in the relative risk of pre eclampsia    in women with    asthma treated with   oral but  not inhaled steroids . However  it is unclear  whether    this is an effect on  steroids or asthma control and severity. 

Although suppression   of the fetal    hypothalamic pituitary   adrenal    axis   is a theoretical    possibility     with  maternal systemic   steroid therapy there is little   evidence    from clinical   practice to support  this .

Long  term high dose   steroids may   increase the risk of preterm    rupture   of the membranes.

There are   concerns regarding    the potential   adverse    effects of steroid   exposure  in utero    and neurodevelopmental problems  in the child. It is   unlikely     that lower   doses of Prednisolone that does    not cross   the  placenta   as well as betamethasone or  dexamethasone will   have similar    adverse   effects.

Oral  steroids  will increase  the risk of infection gestational diabetes and   cause  deterioration in blood   glucose control in women with   established   diabetes   in pregnancy Blood   glucose   should be    checked  regularly the hyperglycaemia is amenable to treatment with diet       metformin  and if required     insulin and is  reversible    or  cessation or reduction   of steroid dose. The development   of hyperglycaemia   is not    an indication  to discontinue or decrease the dose of oral   steroids the    requirements for which     must be    determined by the asthma. Oral  steroids   for medical   disorders in the mother should  not be withheld   because    of pregnancy.

Other  therapies

It is important    to treat any   gastroesophageal reflux as this   can exacerbate    asthma .Studies show no different in perinatal   mortality    congenital malformations birthweight    . Apgar scores or delivery   complications when pregnant women with   asthma   treated   with inhaled B2  agonists are compared   with women  with     asthma   not using   B2   agonists and non asthmatic controls.

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The addition       of systemic corticosteroids to control  exacerbations of asthma  is safe and these must not be withheld if current   medications are inadequate.

No   adverse fetal    effects have been    reported with the use of the   following   drugs

-       Inhaled  chromoglycates  nedocromil

-       Inhaled   anti cholinergic drugs

-       These  are no longer    recommended   as first line treatment    of asthma    but have  been  used extensively  in the past

-       No significant    association   has been demonstrated between major    congenital malformations or  adverse  perinatal  outcome and  exposure   to methylaxanthines.

-       In those   few women      who are    dependent   on Theophylline    , alterations in dose  should be guided by drug    levels. Both  Theophylline and    aminophylline readily cross the placenta   and fetal   Theophylline levels   are similar   to those of the  mother.

Leukotriene   receptor  antagonists

These agents      block   the effects  of cysteinyl leukotrienes   in the airways

Studies  do not    suggest any increased  risk of congenital malformation   or other adverse   outcomes with their use in pregnancy

If  leukotriene    antagonists   are required    to achieve adequate  control of asthma  then they should   not be withheld in pregnancy

Los dose    aspirin

It is  important   to consider   the possibility  of aspirin  sensitivity and  severe   bronchospasm  in a   minority of women   with   asthma .

Low dose    aspirin    is indicated in pregnancy as prophylaxis    for women at high risk of pre eclampsia   antiphospholipid syndrome or migraine prophylaxis

  Pregnant    women with   asthma should be asked about a history of aspirin    sensitivity   before   being  advised to take low dose aspirin and before   using non steroidal anti inflammatory drugs  for pain relief postpartum .

Intrapartum   management

Asthma   attacks in labour are   exceedingly rare because   of endogenous   steroid production. Women should    not discontinue their   inhalers   during labour    and there is   no evidence    to suggest   that B2   agonists   given via  the inhaled   route  impair   uterine  contraction   or delay  the onset of labour.  Women    receiving    oral steroids  should receive    parenteral hydrocortisone to cover the   stress of labour    and until oral   medication   is restarted. Prostaglandin E2 used  to induced labour    to ripen the cervix   and prostaglandin El    for termination     of preganncy or for treatment   or prevention   of     postpartum    hemorrhage   are bronchodilators and    are safe to use.

The use of    prostaglandin    F2a to treat    life threatening   postpartum   hemorrhage  may be   unavoidable   but it can    cause bronchospaem and should  be used    with  caution in  women    with asthma.

All  forms of pain relief in labour   including epidural   analgesia and Entomic can  be used  safely  by women with     asthma    although   in the unlikely  event of an acute   severe    asthmatic attack, opiates for pain    relief   should only  be used with extreme caution . Regional   rather  than  general   anesthesia is preferable   because   of the decreased  risk of chest   infection   and atelectasis.

Ergometrine has  been reported  to cause   bronchospasm in particular   in association   with general   anesthesia  but this    does not    seem to be  a practical problem    when Syntometrine    is used for the prophylaxis of  postpartum hemorrhages.

Restrictions during Breastfeeding is asthmatics??

The risk of   atopic   disease   developing   in the child of a woman with  asthma is about 1 in 10 or 1 in 3 if  both parents are   atopic. There  is some evidence   that breastfeeding may reduce  this risk . This  may be a result   of the delay  in the introduction  of cow’s  milk protein . All the drugs    discussed above  including   oral steroids , are  safe to use in  breastfeeding mothers. Prednisolone is   secreted in breast milk but   there have  been no reported   adverse clinical effects in infants   breastfed by mothers receiving  Prednisolone. Concerns regarding  neonatal  adrenal   function    are unwarranted with  doses  below 30 mg/day  

Effect  of asthma on pregnancy :For   most    women there   are no adverse effects of their asthma on pregnancy outcome. Severe    poorly controlled asthma   associated    with chronic or intermittent maternal hypoxemia may adversely affect   the fetus.

Acuter severe   asthma

Acuter  severe    attacks  of asthma  are dangerous    and should   be vigorously  managed  in hospital .

The treatment    is no different    from the emergency    management   of acute severe asthma    in th non pregnant patient

Women with severe asthma   and one or   more of the   following   adverse   psychosocial factors    are at risk   of death :

-       Psychiatric   illness

-       Drug    or alcohol   abuse

-       Unemployment

-       Denial

-       The features   of acute   severe   asthma are

-       PEFR  33% -50 %   best/  predicted

-       Respiratory     rat > 25 / min

-       Heart    rate > 110  / min

-       Inability to complete  sentences   in one breath

The   management    of acute severe   asthma should    include

-       High   flow oxygen

-       B2  agonists     administered    via a nebulizer driven  by oxygen.

-       B2  agonists    can be administered by repeated   activations of a metered dose    inhaler via  an appropriate large   volume  spacer. Repeated  doses  or continuous  nebulization   may be  indicated for those   with a poor   response. 

-       Nebulized  ipratropium   bromide   should be   added for   severe   or poorly responding   asthma.

-       Corticosteroids   

-       i.v.  rehydration   is often    appropriate

-       Chest X ray should  be   performed   if there is any clinical   suspicion   of pneumonia    or pneumothorax  or if th woman    fails  to improve.

-       IF  the PEFR does     not improve   to > 75 %  predicted   the woman    should be  admitted  to hospital   . If she is discharged this must be  with a course of oral   steroids  and arrangements  for review.

-       Steroids are more likely  to be withheld   from  pregnant than non  pregnant    women   with asthma    presenting    via emergency  departments  . This is inappropriate    and  leads  to an increase  in ongoing   exacerbation of asthma .

-       Life  threatening  clinical   features  are

-       PEFR  < 33%   predicted

-       Oxygen   saturation < 92% 

-       pO2 <8 kPa

-       Normal    or raised pCO2> 4.6kPa

-       Silent    chest   cyanosis   feeble  respiratory  effort  

-       Bradycardia arrhythmia hypotension

-       Exhaustion confusion   coma 

-       Management    of life   threatening   or acute severe asthma   that fails  to respond  should  involve   consultation with the critical care team and consideration  should   be give to

-       i.v. B2  agonists

-       i.v.  magnesium sulphate 1.2-2 g   infusion   over 20  minutes

-       i.v. aminophylline