Maternal migraine

Women who experience migraine in late pregnancy appear to be at higher risk of cardiovascular events, say US researchers. In a population-based sample of almost 34 000 post-partum women, diagnoses jointly associated with migraine at hospital discharge were assessed. Stroke, myocardial infarction, pulmonary embolus, hypertension, smoking, and diabetes were found to be related to migraine. In particular, peri-partum migraine was associated with a 17-fold increase in the risk of pregnancy-related stroke. The authors comment that the link between migraine and vascular disease in pregnancy is most likely due to the existence of overlapping pathophysiological mechanisms, combined with the physiological alterations of pregnancy.

BMJ 2009; 338: b664

Folate in pregnancy

Taking folic acid supplements during pregnancy may be associated with a slightly increased risk of wheeze and lower respiratory tract infection in infants, according to US and Norwegian researchers. In a study involving over 32 000 children born between 2000 and 2005, data were collected on the timing of folate and other vitamin supplementation in pregnancy, and wheezing and respiratory tract infection in children up to 18 months of age. Over 79% of mothers took folate supplements at some point during pregnancy. Women who took folate supplements were likely to be more educated, breastfeed for longer, and less likely to smoke. Wheeze and lower respiratory tract infections were most strongly associated with exposure to folic acid supplements in the first trimester of pregnancy. The authors postulate that the action of folate as a methyl donor may affect the fetus by epigenetic mechanisms influencing gene expression and phenotypes. They also caution that the effect measured was small, and that unmeasured confounding factors may be acting to influence this association.

Arch Dis Child 2009; 94: 180-184

Legacy of Wittenoom

Of the almost 3000 women and girls who lived at the blue asbestos mining and milling town of Wittenoom in Western Australia, 40 had died of malignant mesothelioma by the end of 2004. Australian researchers studying the outcomes for those living in the area between 1943 and 1992 have gone a step further and calculated the predicted mortality from mesothelioma for these women, who were either mine or mill workers, or residents. In the cohort of 2402 women remaining, the authors predict between 66 and 87 deaths up to 2030, with no decline in the number of deaths each year. The model that the researchers used to estimate future mortality included risks from other causes, time since first exposure, lag periods, and rates of clearance of crocidolite from the lungs. They comment that using rate of fibre clearance in the model avoids over-estimation of the predicted number of malignant mesotheliomas, a problem encountered in other studies.

Occup Environ Med 2009; 66: 169-174

Absorbable stents

The use of metallic drug-eluting coronary stents has been controversial because of the association with late stent thrombosis and difficulties with subsequent surgical revascularisation. Bioabsorbable everolimus-eluting stents may be a viable alternative, according to the results of a 2-year clinical follow-up of 29 patients treated with the stents. All participants had a single de-novo coronary artery lesion and were assessed using multiple imaging methods. After 2- years, the biodegradable stent had been absorbed and was incorporated into the vessel wall in all patients. No stent thrombosis occurred and the device appeared safe, with no cardiac deaths and one myocardial infarction in participants. The authors of the small study, which was funded by the stent manufacturers, admit that, although promising, the research has limitations and that results should be interpreted as preliminary findings only.

Lancet 2009; 373: 897-910

Dr Tanya Grassi, MJA

©The Medical Journal of Australia 2009 www.mja.com.au PRINT ISSN: 0025-729X ONLINE ISSN: 1326-5377