Smoking while pregnant can damage both the mother’s and the baby’s thyroid functions, said Padma Shri & Dr. B.C. Roy National Awardee, Dr. KK Aggarwal, President, Heart Care Foundation of India. A British study has shown that cigarette smoke cause babies to be born smaller, to make newborns more likely to die of sudden infant death syndrome, and even to affect the rates of cleft lips, heart defects and other problems. Now it is shown that smoking can also affect the thyroids of both mothers and babies. The study has demonstrated that cigarette smoking at different stages of pregnancy — first trimester and the third trimester is associated with changes in the mothers’ thyroid hormone levels. Good thyroid function is the key to maintaining a pregnancy, and some pregnant women suffer from thyroid imbalances. This, in turn, affects metabolism and the risk of miscarriage, premature birth, low birth weight and impaired brain development. Published in the Journal of Clinical Endocrinology & Metabolism, the study measured the thyroid hormone levels in the umbilical cords of babies born to smoking mothers and found that smoking-related changes in thyroid function also affected the newborn. But among women who quit while pregnant, thyroid hormone levels were comparable to levels found in non-smokers.