Pregnancy and Infant Health
In the beginning, the CHDS was a study of the factors that influenced the healthy progress of pregnancy and infant development. The CHDS resulted in hundreds of scientific publications. Highlights of these accomplishments include:

• Set standards for which blood pressure changes could be considered healthy during pregnancy so physicians would know when a woman needed special care and monitoring
• Found one of the first clues that smoking could damage the unborn baby by causing changes in the placenta (the structure that nourishes the fetus)
• Set standards based on both birth weight as well as length of pregnancy to identify which small babies were at highest risk of early death and disability to allow doctors to identify which children needed special care
• Identified the risk of taking certain drugs during pregnancy. These findings lead to safer pregnancies for all women by alerting doctors to avoid their use in pregnancy.
• Identified which infants were at risk for Sudden Infant Death, helping to identify which children need monitoring.

Child, Adolescent, and Adult Health of CHDS Offspring
The CHDS studies continued to examine the links between experiences in early life, even before birth, and the well being of children across the lifespan. Highlights of CHDS accomplishments in this area include:

• Identified whether convulsions that occur commonly during high fevers in childhood needed to be treated, helping to avoid unnecessary medications that may lead to complications in children.
• Showed that many birth defects may take many years to show up and that studies of birth defects are not complete without following children into childhood.
• Identified differences in birth defects between African American and Caucasian children.
• Established that problems with the muscles of the eye (strabismus) were related to mother's smoking. This helped establish programs to help pregnant women or women planning a pregnancy to quit smoking to protect her baby.
• Identified normal gains in weight and height for children that let doctors decide when a child needs special tests to find out what might be wrong. This allows early treatment to prevent serious health and development problems.
• Showed that when a non-smoking mother was exposed to her husband's smoking during pregnancy, the growth of the baby during pregnancy and during childhood was affected. This helped lead to widely publicized advice to encourage the father not to expose his pregnant partner to secondhand smoke.
• Found characteristics of young children that were related to whether they chose to be smokers as teenagers. This is helping with campaigns to prevent smoking in teens.
• Showed that parent's decisions about how to use medical care affected the health of their children. This has helped doctors and health plans educate parents about when to take their children to the doctor.
• Showed that schizophrenia, a serious mental disorder of that begins in adolescence or young adulthood, may be caused by events that occur before birth [http://www.sciencenews.org/20000701/fob3ref.asp]. This new research may lead to ways to prevent this debilitating disease
• Showed that exposure to some pesticides during pregnancy, could alter the daughter's ability to become pregnant 30 years later [http://www.niehs.nih.gov/dert/profiles/hilites/2003/ddt-dde.htm]. This is expected to lead to understanding about the causes of infertility and the risk of chemicals in the environment to the generations not yet born.

Health of the Parents
As the CHDS parents are aging, we have recently begun studies on how events in young adulthood affect health in mid-life and old age. Our first studies in this area concern breast cancer in CHDS mothers.

One study has identified a special exposure during pregnancy, (alpha-feto protein or AFP) that may protect the breast. We have also identified new protective factors that are related to how the placenta (the organ that nourishes the baby before birth) grows during pregnancy. This work is considered very innovative and promising because it could lead to identifying reasons why a woman's breast is protected during pregnancy. If we can identify the specific ways pregnancy protects the breast, we could use this information to prevent or treat breast cancer in women who are not pregnant or have never have been pregnant. Studies to further develop this area of research are in progress at the CHDS.

Because of the special timing of the pregnancies in the CHDS, during the 1960's, we are able to study the effects of exposure to the pesticide, DDT, which was still in use at that time. Like many other people all around the world in the 1960's, CHDS mothers were highly exposed to DDT. However there are very few studies where actual exposure to DDT can be measured at young ages. We have discovered that CHDS mothers had high levels of this pesticide in their blood, even though they were not generally agricultural workers or exposed on the job. The source of exposure was similar to all human populations in the 1960's—exposure through food and water. The CHDS provides a unique opportunity to study whether DDT exposure at a young age is related to breast cancer. We expect that this research will make a very significant contribution to our understanding of whether exposure to environmental chemicals at a young age affect breast cancer later in life.

Future Plans
We are expecting to begin a major study of the relation of early life events to the quality of semen in CHDS sons very soon. Other planned studies include the investigation of how the timing of menopause is affected by early life events and the study of timing of menarche, fertility, and breast cancer risk across three generations of women.