Biological Markers of Disease in the Prediction of Preterm Delivery, Preeclampsia and Intra-Uterine Growth Retardation: A Longtitudinal Study

* INCLUSION CRITERIA: * Gestational age between 6 and 22 weeks for the first visit based on the patient s last menstrual period as reported by the patient. * High risk group: presence of specific risk factors for preterm delivery, pregnancy-induced hypertension or intrauterine growth retardation. * Low risk group: normal pregnancy with no risk factors for preterm delivery, pregnancy-induced hypertension or intrauterine growth retardation (control population, selected between 6 and 22 weeks at the prenatal care clinic). The rationale to include this group is that 50-70% of preterm deliveries occur in patients without risk factors for preterm birth. * Consent to participate in the study. * Patient should be able to attend each Perinatal Research Center for prenatal care and participation in this study. EXCLUSION CRITERIA: * Preterm labor, preterm PROM, preeclampsia or impaired fetal growth at the time of recruitment. * Any maternal or fetal condition that requires termination of pregnancy. * Known major fetal anomaly or fetal demise. * Active vaginal bleeding. * Multifetal pregnancy with greater than or equal to 3 fetuses. * Serious medical illness (renal insufficiency, congestive heart disease, chronic respiratory insufficiency, etc). * Severe chronic hypertension (requiring medication). * Asthma requiring systemic steroids. * Patient requiring anti-platelet or non-steroidal anti-inflammatory drugs. * Active hepatitis. * Lack of consent.