Smoking
ACTIVITY - Smoking in pregnancy
In your medical course so far you will already have covered some areas of public health problems that can also impact on a pregnancy. Let's start with smoking - you know the effects on the non-pregnant smoker - but what do you think may be the effects on the pregnancy or the fetus if the mother smokes? Have a look at the list of outcomes in the 1st column of the list below. In the 2nd column you can decide whether smoking influences each outcome listed and if so, in the 3rd column whether the risk is higher or lower.
1.Outcome | 2. Does smoking affect the risk ? | 3. If so higher or lower risk? | 4. If so by what %? After you have made a best guess, click the box to see % change |
Infertility | |||
Miscarriage | |||
Ectopic | |||
Cleft lip | |||
Abruption / placenta praevia | |||
Preterm labour | |||
Small for gestational age(SGA) | |||
Stillbirth | |||
Preeclampsia |
As health professionals we need to be asking about smoking and offering support for smoking cessation. We need to ask about this at each antenatal visit and offer women cessation support.
Smoking also has effects on the newborn baby and is the leading cause of sudden unexpected death in infancy (SUDI). Smoking is the single most avoidable risk factor for adverse pregnancy outcome. The effects are dose dependant but the good news is that.....
The risks due to smoking are reversed by stopping smoking
Women who stop smoking by 15 weeks’ gestation will decrease their rates of spontaneous preterm birth, stillbirth and small for gestational age babies so that they are now no different to non-smoking women! You might like to have a look at this BMJ prospective cohort paper from NZ to get more information here. You will probably recognize the author's name!
(Title of paper: Spontaneous preterm birth and small for gestational age infants in women who stop smoking early in pregnancy: prospective cohort study. http://www.bmj.com/content/bmj/338/bmj.b1081.full.pdf).
So if a woman is still smoking, pregnancy is a really good time to motivate her to join smoking cessation programmes. Have a look at the smokefree website for some information about smoking rates in New Zealand. The website will also give you information about the differing rates for different NZ ethnic groups.
Smoking cessation
There are various methods studied to help women stop smoking. Nicotine is the physically addicting substance in cigarettes and nicotine replacement therapy increases cessation rates outside pregnancy. Nicotine replacement (NRT) is ok to use in pregnancy and avoids inhaling all the other toxins in cigarette smoke - here are some of them:
http://www.cancerresearchuk.org/cancer-info/healthyliving/smokingandtobacco/whatsinacigarette
While nicotine replacement therapy has been shown to be probably safe and NRT products are recommended for use in pregnancy, evidence for efficacy is still emerging. Unfortunately RCTs of NRT in pregnancy have not demonstrated increased quitting rates to date. (Ref BMJ 2014;348:g1622 doi:10.1136/bmj.g1622 and SNAP trial N Engl J Med 2012;366:808-18.) This may relate to dosage and type of NRT products used.
However, a recent Cochrane review has shown that incentive-based interventions had the largest effect, however the studies were small. (Cochrane: Psychosocial interventions for supporting women to stop smoking in pregnancy). CMDHB has just completed a pilot with vouchers given up to $300 for women who quit during pregnancy. (https://www.smokefree.org.nz/smokefree-in-action/project-snapshots/counties-manukau-smokefree-pregnancy-incentives-pilot) and this approach has also been adopted by some other DHBs. The incentives are vouchers and given at weekly visits if the pregnant woman remains smokefree. Family members are encouraged to participate too, though the voucher amount is less for other family members compared to the pregnant woman.
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