<qa>  What is the goal of the study?Forty percent of pregnant women in the United States are women who have never given birth. As a group, they sometimes have complications with their pregnancy, but there is no information from a previous pregnancy to identify who might have a problem. Very little research has been done with this group. The Nulliparous Pregnancy Outcomes Study: Monitoring Mothers-to-be nuMoM2b is collecting data from a diverse population of about 10,000 women who are having their first baby and are carrying only one baby. The women are enrolled early in pregnancy and undergo research assessments four times during their pregnancies. Data are collected through interviews, self-completed data forms, clinical measurements, ultrasound, and collection and storage of blood samples, urine samples, and fluid from the vagina and cervix. Some information comes from medical records. A subset of women may be asked to participate in substudies collecting information on sleep breathing, sleep patterns and quality, or other areas possibly related to birth outcomes. The goal of the research is to find ways to identify women in this group who might develop a problem with their pregnancy and use this information to improve the health of pregnant women and their babies in the future. The study is focusing on pregnancy problems like high blood pressure, babies that are born much too early and very small babies. 