Maternal Smoking Status Assessed by Breath Carbon Monoxide Measurements. Association with Fetal Growth and Nicotine Withdrawal Syndrome in Newborns

Background: Maternal smoking during pregnancy is a recognized public health hazard with ill effects on fetal development. Whether infants exposed to tobacco smoke in-utero present with nicotine withdrawal syndrome (NWS) is debated

Aim: To evaluate maternal smoking status by measures of breath CO and analyze its association with fetal growth and Nicotine withdrawal syndrome in newborns.

Methods: Full-term infants were divided into smokers and control groups. Infants' birth parameters correlated with maternal smoking status, neonates’ neuro-behavior assessed during the first 72 hours of life by the Finnegan score.

Results: 29 mother-infant pairs were recruited [11 (4M) smokers' group; 18 (8M) control group]. Smokers were younger (27.2 years versus 29.4 years in the control group, NS), unmarried (P < 0.001), from low socio-economic classes (P < 0.001), and less educated (P < 0.001). Infants born to smokers were lighter in comparison to controls (P < 0.05), the difference in mean BW was more marked in boys (P<0.001). Mean infant BW was also inversely correlated with maternal breath CO: 3213 g (< 5 PPM group), 3185 g (6 - 10 PPM group), and 3176 g (11 - 20 PPM group) (r = 0.952). Assertion of reduction in the smoking habit during gestation was discordant with measured breath CO in smokers, meaning most smokers did not reduce their tobacco consumption substantially. NWS was difficult to ascertain with the Finnegan score, but infants born to smokers presented with symptoms such as irritability, tremors, increased spontaneous Moro's reflex, and poor sleep. They also presented often signs that have the highest scoring items.

Conclusion: Measures of breath CO are reliable in evaluating fetal effects of maternal smoking during gestation. Infants born to smokers present signs in favor of NWS lasting up to 72 hours. Babies require only nursing, no medication is necessary.