ABO blood groups in obstetrics

ABO(H) blood groups and pre-eclampsia

“…Onlythreeofthe studies reported statisticallysignificant findings: one with an excessofgroupAB(9); one with an excessofgroupA (13), and one (24) with adeficit of group O (not attributable to aparticularnon-O group). Upon data extrac-tion afurther study revealed asignificant odds ratio for an excess of group Oincases (25).…”

“…Although therewas evidenceofheterogeneity (p=0.01) and the individual study estimatesw ere relativelyi nconsistent (I 2 49%),t he resultsa re as might be expected for observationalstudiescarried outoversuch along timef rame. Three of the studiesi ndividuallyr eported a significant association when comparing non-O with O(twowith increased risk [13,24] and one showing adecreased risk [25] in association with carriage of non-O). Comparing group Aw ith non-A subjects gave as imilarc umulative odds ratio of 0.96 (CI95% 0.86 to 1.07).…”

“…Limitingthe analysis to thatofprimigravid subjects only produced ac ombined odds ratio of 0.98 (CI95% 0.78 to 1.23) with no evidenceofheterogeneity (p=0.51) or inconsistency(I 2 0%).Asregardsany influenceofblood group on disease severity,the paperbyMay and colleagues (13) examined severe pre-eclampsia, butn oe xcess of non-O waso bservedi n the severe cases examinedinotherstudies (9,26,29). Although aspecific ethnic influencecannot be excluded,itisnotable that twoofthe opposing studies (13,25) were, like14ofthe studies, from either the USA or Europe with both showing asimilarproportion of group Oincontrol subjects of 42.8% (25) and 45.5% (13),r espectively. Fort he whole analysis, although the funnel plot wasa symmetric, there wasn oe videnceo fb iasb ased on eitherthe Eggerweightedregression or Begg'srank correlation methods.…”