A new study published in the JAMA Network Open Journal has found that smoking mothers have an increased risk of getting preterm births.
Notably, the research findings showed that that the probability of preterm birth decreased more, the earlier smoking cessation occurred in pregnancy.
The World Health Organisation (WHO) defines preterm births as babies born alive before 37 weeks of pregnancy are completed.
Because premature babies are born before they are physically ready to leave the womb, they often have health problems. These newborns have higher rates of disabilities such as cerebral palsy and even death.
During the research, the investigators sought to assess the probability of preterm birth among expectant mothers who smoked before pregnancy and quit at the start or during pregnancy.
Using data from the US National Centre for Health Statistics, they conducted a cross-sectional study of more than 25 million pregnant women of between 25 and 29 years who gave birth to live neonates during a six-year period (2011-2017).
They measured the smoking frequency of the mothers three months prior to pregnancy and for each trimester during pregnancy.
The study findings showed that quitting smoking was associated with a reduced risk of preterm births.
Notably, the results also showed that the probability of preterm birth decreased more, the earlier smoking cessation occurred in pregnancy.
Indeed, the research revealed that the risk of preterm births decreased by up to 20 percent if cessation occurred at the beginning of pregnancy.
Despite these benefits, the study found that only about 25 percent of women who smoked prior to pregnancy were able to quit throughout their pregnancy.
Worse still, about 50 percent of women who smoked during their pregnancy did so with a high frequency (more than 10 cigarettes per day).
The researchers noted that despite the benefits of smoking cessation for expectant women, the proportion of smoking mothers who quit the habit during pregnancy is still low.