Q2. What are the future works mentioned in the paper "A meta-analysis of adverse perinatal outcomes in women with asthma running title: adverse perinatal outcomes in women with asthma" ?
Further studies should define optimal management strategies to improve asthma control during pregnancy and prevent exacerbations, with the aim of reducing perinatal complications. In the meantime, despite some heterogeneity, the increased risks demonstrated in these analyses of pregnancies of asthmatic women, suggest that careful medical and obstetric monitoring of the asthmatic mother and her developing baby are warranted.
Q3. How often should women have their asthma monitored during pregnancy?
Since changes in asthma course during pregnancy can be unpredictable and not always consistent between pregnancies for the same woman 69, it is recommended that women have their asthma monitored at least monthly during pregnancy 70.
Q4. What could be the effect of maternal hypoxia on fetal growth?
Maternal hypoxia could influence fetal oxygenation 54 with consequences for fetal growth via alterations of placental function 55-61.
Q5. What was the effect of the Egger test on the outcomes of the study?
When outcomes were reported in at least 10 studies, Funnel plots and the Egger test were used to investigate study size effects, indicative of possible publication bias (Stata 7).
Q6. Why is the heterogeneity overstated in the meta-analysis?
It is likely that the heterogeneity is overstated in their meta-analysis compared to traditional meta-analyses due to the very large sample sizes of some of the retrospective cohort studies.
Q7. What was considered unfeasible to search non-English language publications?
Hand searching and reference checking of articles was not conducted and it was considered unfeasible to search non-English language publications.
Q8. What is the likely explanation for the heterogeneity of the study?
In addition the authors investigated confounders as contributors to the heterogeneity between studies using meta-regression and in almost all cases there was no change in effect size making it less likely that confounding explains the observations in the current metaanalysis.
Q9. What is the link between asthma and pre-eclampsia?
A common pathway leading to hyperactivity of the smooth muscle in both the bronchioles and the myometrium has been proposed to explain the increased incidence of preterm labour in women with asthma 13, 65, 66; a common pathway of mast cell infiltration has been proposed to explain the connection between asthma and pre-eclampsia 67.
Q10. What was the effect of asthma on fetal growth?
Analysis of data from 3 studies on high birth weight (>4 kg) 6, 16, 46 was supportive of the effect of maternal asthma on fetal growth (RR 0.84, 95% CI 0.74, 0.96, no heterogeneity).
Q11. What are the main reasons for the increased risk of preterm birth?
If the association between maternal asthma and poor perinatal outcome is indeed real, there are three main explanations could account for the increased risk.
Q12. What was the RR of the no active management sub-category?
This subcategory was adequately powered to detect a RR of 2.19 (100% power) as observed in the no active management sub-category.
Q13. What were the possible inclusion criteria for the study?
English language studies published between 1975 (when inhaled corticosteroids were introduced) and March 2009 were identified for possible inclusion from Medline (n=1642), Embase (n=1755), CINAHL (n=417), and the Cochrane Clinical Trials Register (n=75), using the search terms ((asthma or wheeze) and (pregnan* or perinat* or obstet*)).