Complications of Pregnancy ebooksclub.org Tobacco or Health Physiological and Social Damages Caused by Tobacco Smoking Second Edition
Remarkably,therateofpre-eclampsiahasbeenreportedtobelowerinheavysmokers thaninnon-smokers11.3vs.13.0;OR=0.85;CI:0.73–0.99.However,smokers
withpre-eclampsiahadhigherratesofinfantswithverylowbirthweightOR=1.85; CI:1.55–2.20andhigherratesofplacentalabruptionOR=3.49;CI:1.65–7.28
[43] .
Morediscriminatinginformationonmalformationsisprovidedbyastudyfromthe USAinwhich3,284livebirthsofwomenwhosmokedwerecomparedwith4,500live
birthsofnon-smokers.Whenallmalformationswereconsideredasagroup,noincreased riskwasassociatedwithmaternalsmoking.However,whenspeciicmalformationswere
considered separately, signiicant associations with maternal smoking were found for microcephalus,cleftdefectsandclubfoot,butnotforDownsyndromeTable
8.5
[48] .
Atrialseptaldefectsarereportednottobeattributabletosmokingduringpregnancy [52]
. Onesurveyof12,914pregnanciesand10,523livebirthshasshownthattherisksofspon-
taneousabortionandcongenitalabnormalityinsmokingmothersare1.7-and2.3-foldhigher, respectively,thaninnon-smokers
[62] .Similarindingswerereportedinanotherstudypub-
lishedinthesameyearshowingthatsmokers20cigarettesdayhada1.6-foldincreased riskofgivingbirthtoaninfantwithcongenitalmalformations
[63] .Theinfants’birthweight
isreduced [64–67]
,andpretermdeliveriesaremorecommon [68]
,becauseofthepossibility ofdisturbancesofplacentalmaturationresultingfromintrauterineO
2
deiciency.Asdemon- stratedinagroupof770,744babiesborninGermanyin1999,154,149ofthemwerebornof
smoking mothers [2]
. A dose-dependent and age-dependent reduction of the mean birth weightwascalculatedFig.
8.1 .Ithasalsobeensuggestedinthiscontextthattheinfants
affectedhavealowerIQ [69,70]
,assubstantiatedbyaprospectivestudyin19,117children. LowIQvaluesweredetectedwhennootherneurologicalabnormalitieswerepresent.InaUK
studyconductedinchildrenaged9.4yearswhosemothershadsmokedduringpregnancy,no adverseeffectsonIQorcognitivedevelopmentweredetectedcomparedwithcontrols
[71] .
Astudyconductedin227,791livebirthsinWestphaliaclearlyshowedanassociation between LBW and cigarette consumption during pregnancy 10 cigarettesday
[72]
seeTable 8.4
.Similarly,smokingAfricanAmericanwomenfromlow-incomegroups werereportedtobemorelikelytohaveLBW2,500gandpreterm37weeks’gesta-
tionbirths.Whenlightsmokerswerecomparedwithnon-smokers,theoddsratioswere 1.89CI:1.15–3.13forLBWbirthsand1.74CI:1.00–3.02forpretermbirths.When
heavysmokerswerecomparedwithnon-smokers,theoddsratioswere3.03CI:1.90–4.86 forLBWbirthsand2.60CI:1.55–4.35forpretermbirths
[74] .AccordingtoaSwedish
study in pregnant women who smoked, male foetuses were affected signiicantly more
Enzymesystem Geneticvariant
n Birthweight
reductiong OR95CI
CYP1A1 None
−377±89 2.11.2–3.7
CYP1A1 AA
75AA −252±111
1.30.6–2.6 CYP1A1
AAaa 43Aa,6aa
−520±124 3.21.6–6.4
GSTT1 Present
−285±99 1.70.9–3.2
GSTT1 Absent
−642±154 3.51.5–8.3
CYP1A1–GSTT1 AAaa+absent
−1,285±234 p0.001
Table 8.3
InluenceofgeneticvariantsofCYP1A1andGSTT1onthebirthweightofinfantsborn to174smokingand567non-smokingpregnantwomen
[42]
frequentlyandseverelythanfemalefoetusesintermsofgrowthretardationassessedin uterobiparietaldiameter,subscapularfataccretion.Inboysbutnotgirlsborntosmok-
ers,headcircumferencewasalsosigniicantlysmaller [81]
. Duringaprospectivecohortstudyof30,681pregnanciesofatleast28weeks’gesta-
tion,307womenca.1hadplacentalabruptions.Eachpackofcigarettessmokedper dayincreasedtheriskofplacentalabruptionby40OR=1.39;CI:1.09–1.79,witha
3800 3600
3400 3200
3000 2800
2600
Birth Weight [g]
16 20
24 28
32 36
40
Age [years] of the para
Difference: −252 g −341g
−456 g
Fig. 8.1
Mean birth weight of children of non-smoking upper line and of smoking pregnant women 6–10 cigarettesday; middle line; or 21–60 cigarettesday; lower line. The data were
calculatedindependenceofthepara’sage [2]
Risks OR
References Prematureplacentalabruption
30,681pregnancies Inca.1;OR1.39
[42,73] Reductioninbirthweight
−200–300g [2,42,64,65,74–78]
LBW227,791livebirths −239g;−1.41cm;
BMI−0.6kgm
2
[72] LBW1,011pregnancies
−205g;−1.28cm;−0.38cm headcircumference
10cigarettesday [79]
Suddeninfantdeathsyndrome SIDS
Riskincreasedby2.2-to 8.4-fold,dependingon
study,alsodependingon thenumberofcigarettes
smoked [80]
SpontaneousabortionsSpand malformationsMF12,914
pregnancies.+10,523livebirths 1.7-foldSpand2.3-fold
MFincrease [62]
Table 8.4
Riskstopregnancyassociatedwithcigarettesmoking
concomitant increase in perinatal mortality. Placental abruption was also signiicantly associatedwithintrauterinegrowthretardationandfoetalmalformations
[82] .
ThecommonlydetectedpresenceofO
2
deiciencyinthebloodofwomenwhosmoke isattributabletotheelevatedCOlevels
[83] ,aphenomenonthatisassociatedwiththe
increasedformationofCO–haemoglobin.ThepathogeneticimportanceofCOisindicated bycasesofCOpoisoningduringpregnancyculminatinginthedeliveryofmalformed
infantsseeSect. 8.5
. Accordingtootherinvestigations,theriskofspontaneousabortion
[84] andperinatal
mortalityareincreasedinpregnantwomenwhosmoke [85]
.