The evidence that cigarette smoking has harmful effects on the fetus is strong. Maternal smoking reduces birth weight. The effect of smoking on pre-eclampsia, other perineal outcomes and subsequent child development is more complicated.
Smoking remains one of the few potentially preventable factors associated with low birth weight, very preterm birth and perineal death.
For this reason it is an important public health issue in pregnancy. Smoking is also associated with low rates of initiation of breastfeeding, and reduced duration, although whether this is a casual relationship is uncertain. Up to quarter of women who smoke before pregnancy stop before their first antenatal visit.
Smoking is more common among women with social disadvantage, high parity, no partner, low income, or receiving Medicaid –funded maternity care. Women with psychological problems, such as depression, job strain, excessive work load, and low levels of practical support are also likely to smoke more than women without these disadvantages.
The damaging effects of excessive alcohol consumption in pregnancy are well known. They include: fetal growth restriction, mental retardation and a dysmorphic syndrome with variable features and altered neonatal behavior. Developmental abnormalities are associated only with regular consumption of at least 28.5 ml of alcohol per day. Moderate alcohol consumption has not been associated with adverse perineal and infant outcomes.
Campaigns to increase public awareness of the dangers of alcohol during pregnancy run the risk of arousing anxiety in some women already pergnat,partly because of the uncertainty about the safe lower limit of alcohol intake and also because of the possibility that the most dangerous time for dysmorphic effects may be the first trimester,
some tomes even before women know that they are preganat.The very first weeks of pregnancy are often reported to be a period of high anxiety and depression that may increase drinking to relieve tension.
Policy development on alcohol and pregnancy requires, first of all, clarification as to the degree of risk around conception for low levels of regular alcohol consumption.
Marijuana: There is limited information on the effects of marijuana use in pregnancy. In newborn babies, maternal marijuana use was associated with mild withdrawal symptoms. Between 6 months and 3 years of age, however, no behavioral consequences of marijuana exposure are noted.
No effects on motor development, including balance and ball handling are identified. But sleep disturbances in the offspring are sometimes present.