A Follow-up of the Early Pregnancy Study Cohort.
Condition: Gestational Age; Time to Pregnancy; Early Pregnancy Loss
MeSH terms: Abortion, Spontaneous
Study type: Observational

Summary: 
      Background:

      - The purpose of the 1982 1986 North Carolina Early Pregnancy Study was to determine how
      often pregnancy loss occurs before women know they are pregnant. Women planning to become
      pregnant were asked to collect daily urine specimens and fill out daily diaries of their
      intercourse and menstrual bleeding. Researchers are interested in re-contacting this cohort
      to gather new information and to examine how accurately women can recall events that occurred
      earlier in their lives.

      Objectives:

      - To follow-up with and gather additional information from women who were involved in the
      Early Pregnancy Study.

      Eligibility:

      - Women who participated in the 1982 1986 North Carolina Early Pregnancy Study.

      Design:

        -  Participants will receive and complete a questionnaire that includes the following
           topics:

        -  Their pregnancy history.

        -  The infant s birth, including method of delivery and induction of labor.

        -  Early life exposures such as their own birth weight and their parents ages at their
           birth.

        -  Tap water use during their attempt to conceive

        -  General description of their behaviors during their participation in the original study,
           these include: physical activity, caffeine, alcohol, and soy food consumption.

        -  Participants will return the surveys to the researchers in the stamped envelope provided
           with the questionnaire....
    

Detailed description: 
      We propose a follow-up study of women who participated in the North Carolina Early Pregnancy
      Study (EPS) in 1982-1986. Women enrolled in the study after discontinuing birth control and
      were followed for the occurrence of a pregnancy. Participants completed daily diaries and
      collected first morning urine specimens which allowed the identification of menstrual cycles.
      Thus each woman s time to pregnancy was prospectively measured. We intend to trace the women
      and ask them to complete a questionnaire that includes their recall of their time to
      pregnancy during the study. This will allow us to address two major questions, one regarding
      the recall of time-to-pregnancy, and the other regarding the natural length of gestation. In
      addition, we will investigate associations of bisphenal A (BPA), phthalate metabolites, 2,4-
      and 2,5-dichlorophenols, Triclosan, benzophenone-3, and methyl-, propyl- and butyl-parabens
      with reproductive outcomes. This is described in a separate section at the end of this
      protocol because it does not involve recontacting participants, only assay of stored urine
      samples for purposes within the goals of the original study.

        1. Recall of time-to-pregnancy

           Time to pregnancy is a commonly studied estimate of fecundability. This outcome has been
           used to study the reproductive effects of environmental toxins, cigarette smoking,
           obesity and numerous other exposures. Prospective studies of time to pregnancy require
           enrollment of women who are just starting to attempt pregnancy and following them until
           a pregnancy is conceived. This type of study can be time-consuming and costly. It is
           also difficult to identify a population of women who are just beginning to attempt
           pregnancy. A more efficient design is to ask women to recall their time to pregnancy.
           This design is limited however, as it is unknown how well women can recall their time to
           pregnancy. Only two studies have examined this question in a population with both
           prospective and retrospectively recalled time to pregnancy. One of the studies involved
           women from the Netherlands, the recall period was short (3-20 months), and only part of
           the woman s time to pregnancy was prospectively observed. The second study had a longer
           recall period (1-10 years) but included only 43 women.

        2. Length of gestation

      Gestational length is the time from conception to delivery. The EPS has very good data on the
      first data point, and we know date of delivery. However, our data on delivery is limited by
      the fact that we do not know which deliveries were induced and which were the product of
      natural onset of labor and delivery. We plan to collect this information from the mothers.
      Such information will not only allow us to consider the natural variability in gestational
      age (a measure that does not exist at present) but also to estimate associations between
      events in very early pregnancy and the subsequent duration of pregnancy. The EPS has detailed
      measurements of the time from ovulation to implantation, the rate of increase in human
      chorionic gonadotropin and corpus luteum rescue. To our knowledge, these early pregnancy
      characteristics have not been investigated for associations with length of gestation.
    

Observational model: Cohort
Time perspective: Retrospective
Sampling method: Non-Probability Sample
Study population: 
        Women who participated in the 1982-1986 North Carolina Early Pregnancy Study (EPS)
      
Keywords: Early Pregnancy; Gestational Age; Fecundability; Ovulation; Recall; Natural History