Links between Smoking During Pregancy and Sudden Death Syndrome (SIDS)

While recent campaigns to promote the sleeping of infants on their back have been very successful, the rate of SIDS in New Zealand still remains unacceptably high. Smoking during pregnancy has been linked to a five-fold greater risk of the infant dying of Sudden Infant Death Syndrome. However, the exact nature of this link has yet to be elucidated.

What are your research objectives?

We hope to determine whether specific Monoamine Oxidase B (MAOB) enzyme inhibitors recently found in cigarette smoke, pass over the placenta and alter the levels of dopamine, in the fetal heart and carotid body. Such an alteration could mean problems in blood oxygen and blood pressure sensing, postnatally affecting an infant’s ability to wake during an episode of sleep apnea. This would help explain the five-fold greater risk of SIDS in infants born to mothers who smoke during pregnancy. It may also have implications for suspected SIDS postmortem examinations in the future.

How you will conduct your research?

This is a laboratory based study involving a pregnant rat model. Cigarette smoke solutions will be infused into pregnant rats and the effects on enzyme activities in the heart and carotid body of fetal and postnatal rats will be examined. No children are directly involved. However, it is anticipated that the results of such studies may be important for postmortem examinations in SIDS cases, as well as being of importance for educating expectant mothers, about the risks of smoking during pregnancy.

Are there others in your field in NZ or globally conducting similar research?

There is no other research in New Zealand examining the link between maternal smoking and SIDS. Globally there are a small number of other research groups examining this link.

What is innovative about the approach you are taking?

Other research groups have focused on the potential role of nicotine on the fetal and postnatal brainstem and waking reflex. However, our research is the only study to examine how other compounds in cigarette smoke may inhibit certain enzymes, and reduce the effectiveness of the postnatal blood oxygen and blood pressure sensing systems. These sensing systems are crucial to an infant’s waking reflex during an episode of sleep apnea. We hypothesize that compounds in cigarette smoke act not only on the brain stem, but in crucial sensors in the peripheral nervous system, so that warning signals may not even reach the brain.

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