U. NOTTINGHAM (US) — Pregnant non-smokers who breathe second-hand smoke have a 23 percent higher risk of delivering a baby that is stillborn and a 13 percent higher risk of having a baby with birth defects.
The findings underline the importance of discouraging expectant fathers from smoking around their pregnant partners and warning women of the potential dangers of second-hand smoke both pre-conception and during pregnancy.
“Mothers’ smoking during pregnancy is well-recognized as carrying a range of serious health risks for the unborn baby including fetal mortality, low birth weight, premature birth and a range of serious birth defects such as cleft palate, club foot, and heart problems,” says Jo Leonardi-Bee, lecturer in medical statistics at the University of Nottingham.
“Since passive smoking involves exposure to the same range of tobacco toxins experienced by active smokers, albeit at lower levels, it is likely that coming into contact with second-hand smoke also increases the risk of some of all of these complications.”
The international study, published in the journal Pediatrics, draws its findings from a review of 19 studies carried out in North America, South America, Asia, and Europe and is centered on pregnant women who did not smoke themselves but were exposed to second-hand smoke in the home by their partners or in the workplace by colleagues.
The research looked at the potential effects of passive smoking on miscarriage, newborn death and congenital birth defects.
The study did not find an increased risk of miscarriage or newborn death from second-hand smoke and was not associated with any one congenital defect—the overall increase was only seen after pooling the results from all the studies.
Fathers who smoke pose danger they pose to their unborn child, says Leonardi-Bee. Also, since it remains unclear when the effects of the second-hand smoke women should be protected from passive smoking both before and during pregnancy.
“What we still don’t know is whether it is the effect of sidestream smoke that the woman inhales that increases these particular risks or whether it is the direct effect of mainstream smoke that the father inhales during smoking that affects sperm development, or possibly both,” says Leonardi-Bee.
“More research is needed into this issue although we already know that smoking does have an impact on sperm development, so it is very important that men quit smoking before trying for a baby.
“We also need to continue to find other good public health interventions that can reduce the exposure of these women to passive smoke. One possibility could be for the partner to use smoking cessation treatments such as nicotine replacement therapy (NRT) patches as temporary abstinence interventions in the home and car when they are in the company of the woman.
“The risks are related to the amount of cigarettes that are smoked—the data suggests that being exposed to around 10 cigarettes a day is enough for the risks to be increased so it is therefore very important for men to cut down.
“Ultimately though, in the interests of their partner and their unborn child the best option of course would be to give up completely.”
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