fetal alcohol spectrum disorders (FASD). The exact interaction between ethanol and the developing fetus is complex and largely uncertain, however, several direct and indirect effects have been observed as the fetus matures. Predominant among these are irregularities in the fetus's endocrine, metabolic and physiological functions. Smoking The negative consequences of smoking are well-known, and these may be even more apparent during pregnancy. Exposure to tobacco smoke during pregnancy, commonly known as in utero maternal tobacco smoke exposure (MTSE), can contribute towards various problems in babies of smoking mothers. About 20% of mothers smoke whilst pregnant and this is associated with increased risk of complications, such as preterm birth, decreased fetal growth leading to lower birth weight, and impaired fetal lung development. Drugs There is evidence pointing towards pharmacological programming of the fetus during the first trimester. One type of drugs which is suspected of influencing the developing baby when used during pregnancy is anti-hypertensive drugs. Pre-eclampsia (a condition of hypertension during pregnancy), is a serious problem for the majority of pregnant mothers and can predispose the mother to a variety of complications, including increased risk of mortality and problems during parturition. References External links MRC Lifecourse Epidemiology Unit page at the University of Southampton Fetal Programming page on the Centre for Fetal Programming's website. Women's health Human pregnancy Epigenetics Embryology