Although all drugs have risks, I am not aware of tetanus shots causing problems during pregnancy.

There are actually two different kinds of tetanus shots. One, called tetanus toxoid, is used to reduce the risk of tetanus. Tetanus toxoid is administered as a primary immunization designed to stimulate the immune system to identify and react to the bacteria that cause tetanus. Most of us received our first tetanus shot when we were children. Public health experts recommend a "booster" shot every 10 years. If a person has not had a recent booster shot, tetanus toxoid is administered at the time of an injury when there may be a risk of tetanus. Tetanus toxoid is usually given in combination with diphtheria toxoid.

Tetanus immune globulin is the second type of tetanus shot. It is only administered if there is a strong likelihood that a person may develop tetanus or has evidence of the disease from an injury. Tetanus immune globulin provides a "passive" form of immunity that gives immediate protection from tetanus. However, tetanus immune globulin is not long-lasting. A follow-up dose of tetanus toxin is usually given sometime after the acute injury.

All drugs have risks, and tetanus toxoid and immune globulin are no exceptions. However, there is no evidence that either tetanus toxoid or tetanus immune globulin poses a risk to pregnancy. In general, the benefits of decreasing risk of tetanus far outweigh any risk of either tetanus toxoid or tetanus immune globulin.

Although it is always advisable to avoid any unnecessary drugs during the first trimester of pregnancy, the risk of tetanus toxoid and immune globulin are very low. The risks and benefits of getting either the toxoid tetanus shot or the immune globulin during the first trimester should be carefully evaluated.