Smoking negatively affects fertility of both women and men spontaneously and in IVF programmes. By accelerating egg depletion, smoking leads to a chronological increase in approximately 10 years with regards to IVF outcome. Further, lower birth weight, a higher risk of oral facial clefts and sudden infant death syndrome are associated with maternal smoking. In men smoking is associated with an increased risk of producing sperm of reduced quality and concentration.
Excessive alcohol consumption is associated with reduced conception, lower pregnancy rates and higher miscarriage rates. The known effects of alcohol consumption are physical anomalies, behavioural and cognitive deficits, fetal death, preterm labour and compromised fetal growth.