Smoking during pregnancy may harm the later-life aerobic fitness of male offspring, according to researchers.
It is well established that smoking during pregnancy can cause harm to both mother and baby; it can raise the risk of preterm birth, birth defects and infant death.
Despite these risks, many expectant mothers continue to smoke; according to the Centers for Disease Control and Prevention (CDC), data for 2011 from 24 US states found around 10% of women reported smoking during the last 3 months of pregnancy.
Now, lead study author Dr. Maria Hagnäs, of the University of Oulu in Finland, and colleagues suggest smoking during pregnancy may impact the aerobic fitness of male offspring later in life.
"Our study adds to the existing evidence base of the negative and long-standing impacts of maternal smoking," says Dr. Hagnäs.
The researchers publish their findings in BJOG: An International Journal of Obstetrics and Gynaecology - a journal of the UK's Royal College of Obstetricians & Gynecologists (RCOG).
Study highlights need for pregnant women to quit smoking
To reach their conclusion, the team assessed the aerobic fitness of 508 men with an average age of 19 through a 12-minute running test, known as the Cooper test.
Aerobic fitness reflects the ability of the body to take in and use oxygen during aerobic exercise in order to supply energy to the muscle cells; the lower one's aerobic fitness, the less oxygen the body ingests. Examples of aerobic exercise include walking, jogging, running, swimming and cycling - activities that require the heart, lungs and muscles to work hard.
Fast facts about smoking
- Around 18 in every 100 adults in the US currently smoke
- Smoking is the leading preventable cause of disease and death
- More than 16 million Americans are living with a smoking-related disease.
The researchers also gathered data on the smoking status of participants' mothers during pregnancy, as well mothers' pre-pregnancy body mass index (BMI) and weight gain during pregnancy.
Of the men included in the study, 59 of their mothers smoked at least one cigarette daily throughout their pregnancy.
The team found men whose mothers smoked during pregnancy demonstrated lower aerobic fitness on the running test than those whose mothers did not smoke.
This finding was independent of BMI of both mothers and offspring, as well as the smoking status and physical activity of offspring.
In addition, the researchers identified lower aerobic fitness among men whose mothers experienced excessive weight gain during pregnancy and who had high pre-pregnancy BMI, but they found this risk was mediated through the weight of offspring.
The team says their findings add to growing evidence of the long-term health risks maternal smoking can have on children's health, emphasizing the need for expectant mothers to quit the habit.
Dr. Geeta Kumar, chair of RCOG, says:
"Stopping smoking is one of the most important things a pregnant woman can do to improve their baby's health, growth and development, and this study demonstrates the negative effect smoking in pregnancy can have on a child's long-term health too."
"Women must receive advice and support to help them stop smoking during pregnancy, as well as guidance on how to maintain a healthy weight to minimize the risks to their unborn child," adds Dr. Hagnäs.
Our Knowledge Center article "How to Give Up Smoking" provides some useful tips on how to quit the habit.