Patterns and predictors of vaginal bleeding in the first trimester of pregnancy.
OBJECTIVE
Although first-trimester vaginal bleeding is an alarming symptom, few studies have investigated the prevalence and predictors of early bleeding. This study characterizes first trimester bleeding, setting aside bleeding that occurs at time of miscarriage.


METHODS
Participants (n = 4539) were women ages 18 to 45 enrolled in Right From the Start, a community-based pregnancy study (2000-2008). Bleeding information included timing, heaviness, duration, color, and associated pain. Life table analyses were used to describe gestational timing of bleeding. Factors associated with bleeding were investigated by the use of multiple logistic regression with multiple imputation for missing data.


RESULTS
Approximately one fourth of participants (n = 1207) reported bleeding (n = 1656 episodes), but only 8% of women with bleeding reported heavy bleeding. Of the spotting and light bleeding episodes (n = 1555), 28% were associated with pain. Among heavy episodes (n = 100), 54% were associated with pain. Most episodes lasted less than 3 days, and most occurred between gestational weeks 5 to 8. Twelve percent of women with bleeding and 13% of those without experienced miscarriage. Maternal characteristics associated with bleeding included fibroids and prior miscarriage.


CONCLUSIONS
Consistent with the hypothesis that bleeding is a marker for placental dysfunction, bleeding is most likely to be observed around the time of the luteal-placental shift.
Epidemiology Branch, National Institute of Environmental Health Sciences, Research Triangle Park, NC 27709, USA. reem_hasan@med.unc.edu <reem_hasan@med.unc.edu>
Reem
R
Hasan
Donna D
DD
Baird
Amy H
AH
Herring
Andrew F
AF
Olshan
Michele L
ML
Jonsson Funk
Katherine E
KE
Hartmann
D000022:Abortion, Spontaneous / Q000453:epidemiology; D000293:Adolescent; D000328:Adult; D000367:Age Factors; D016001:Confidence Intervals; D004522:Educational Status; D005260:Female; D006801:Humans; D007889:Leiomyoma / Q000150:complications / Q000453:epidemiology; D016015:Logistic Models; D008875:Middle Aged; D016017:Odds Ratio; D011247:Pregnancy; D011261:Pregnancy Trimester, First; D015995:Prevalence; D011446:Prospective Studies; D012720:Severity of Illness Index; D012959:Socioeconomic Factors; D014481:United States / Q000453:epidemiology; D014592:Uterine Hemorrhage / Q000453:epidemiology* / Q000209:etiology; D055815:Young Adult