Hormonal Changes in Early Pregnancy

Study Summary

This study will analyze hormones in early pregnancy. Hormonal changes in early pregnancy reflect the quality of implantation in the uterus of the fertilized egg, the function of the corpus luteum (mass of hormone-secreting tissue that forms immediately after ovulation) and placenta, and the health of the embryo. It will determine the following: * Whether early pregnancy hormones vary by characteristics of the mother * Whether early pregnancy hormones differ for pregnancies with male or female babies * Whether early pregnancy hormones can predict the gestational age (age of the baby during pregnancy) and the baby's birth weight * Hormone activity at the time pregnancy symptoms begin * How the contribution of the corpus luteum changes during the pregnancy in different women Stored urine specimens collected from women who participated in the North Carolina Early Pregnancy Study in the 1980s will be used for this study. In addition, to evaluate the quality of the stored samples, new specimens will be collected from women currently enrolled in the University of North Carolina's Right from the Start study. Candidates must be white women not of Latino or Hispanic origin who are between 25 and 35 years of age and who are planning to become pregnant within a few months' time. They must be non-smokers, have regular menstrual cycles, no known fertility problems and no major chronic disease. Urine specimens are analyzed for hormone levels and other changes in early pregnancy that can be measured in urine. Women providing new urine specimens do the following: Pre-Pregnancy The pre-pregnancy part of the study lasts through no more than three consecutive menstrual cycles. Participants who do not become pregnant after three menstrual cycles end the study at that time. * Have a short interview with a study staff member * Complete a daily diary, recording any vaginal bleeding or spotting, health status, and use of medications, and mail the diary to the study office once a week