| It is unlikely that moderate smoking or drinking during the first month of pregnancy will be harmful. But it is very important for a woman to stop smoking or drinking as soon as she knows she is pregnant — whether she smokes and drinks moderately or heavily.
It’s always best to prepare for the birth of a child before pregnancy. But if preconception planning is not possible, a woman still can prepare during pregnancy. The key is taking good care of her health, which includes eliminating or reducing any toxins in her system as well as having good prenatal care. It will help ensure a healthy pregnancy — from embryo, to fetus, to the birth of her child. The healthier a woman is, the stronger she and her child are likely to be.
There are two important points to remember about toxins that can damage the developing fetus:
- The most sensitive period for causing birth defects is the fifth to the 10th week after the last menstrual period (the third to eighth week of gestation).
- Damage to the fetus includes injuries that are not birth defects, such as low birth weight, premature delivery, respiratory problems, developmental delays, or even death. The damage that comes from smoking, drinking, or other toxins is, in general, cumulative. This means that the safest way to prevent toxin-related damage is to stop toxin exposure before pregnancy. The longer and heavier a woman smokes, drinks, takes other drugs, or is exposed to other toxins, the more the fetus is at risk of harm.
The pre-embryo — the developing ball of cells — is not exposed to whatever toxins are in a woman’s bloodstream during the several days after fertilization and before implantation. But after implantation, the embryo begins to receive toxins, as well as nutrients, from the woman’s bloodstream. Several days after implantation, a woman will miss her period, may suspect that she is pregnant, and take a pregnancy test. Once she knows she is pregnant, she must stop letting toxins get into her bloodstream.
Preconception planning provides women with time to identify and clear their systems of toxins before becoming pregnant. It may not be possible, however, for all women to plan their pregnancies. But all women who decide to bring a pregnancy to term should arrange for prenatal care as soon as they discover they are pregnant. Women who smoke, drink, use other drugs, or are exposed to toxins in the workplace should talk with their clinicians to develop plans for stopping or for referrals to programs that can help them break their smoking, drinking, or other drug habits. With the help of a health care provider, women exposed to toxins at work may be able to change their work environments in order to minimize exposure to those toxins.
It is also important for toxin-free women to see a clinician regularly for prenatal visits to help ensure a healthy pregnancy. Women who receive prenatal care are less likely to have serious problems related to pregnancy. And babies are much more likely to be born at a healthy birth weight if their mothers received adequate prenatal care. | 
