Vaginal bleeding in very early pregnancy

Department of Epidemiology, School of Public Health, University of North Carolina, Chapel Hill, NC 27599-7435, USA.
Human Reproduction (Impact Factor: 4.57). 09/2003; 18(9):1944-7. DOI: 10.1093/humrep/deg379
Source: PubMed


Little is known about the occurrence and patterns of vaginal bleeding during the earliest stages of pregnancy. We explore this in a prospective study of early pregnancy.
A total of 221 healthy women kept daily diaries and provided daily urine samples while trying to become pregnant. Of these, 151 women became clinically pregnant [i.e. pregnancy that lasted >/=6 weeks beyond last menstrual period (LMP)] during the study. Diaries provided information on days with vaginal bleeding and sexual intercourse. Urine hormone assays were used to identify ovulation and implantation. Women were interviewed about their medical histories and lifestyle factors.
A total of 14 women (9%) recorded at least 1 day of vaginal bleeding during the first 8 weeks of pregnancy. Twelve of these 14 pregnancies continued to a live birth. Bleeding tended to occur around the time when women would expect their periods, although rarely on the day of implantation. Bleeding was not associated with intercourse.
Early bleeding in clinical pregnancies is generally light, and not likely to be mistaken for LMP. Thus, early bleeding is unlikely to contribute to errors in LMP-based gestational age. We found no support for the hypothesis that implantation can produce vaginal bleeding. Similarly, intercourse did not cause bleeding. Nearly all women with bleeding went on to have successful pregnancies.

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    • "Several biological mechanisms during pregnancy that may lead to bleeding and PTB have been proposed, including aberrations in the coagulation cascade and platelet activation (Lockwood, 2006). However, it is difficult to document patterns of bleeding, particularly in early pregnancy (Axelsen et al., 1995; Harville et al., 2003; Yang et al., 2005) and as a result the causes of first-trimester bleeding that result in a PTB rather than pregnancy loss are few (Salafia et al., 1995; Chen et al., 1996; Yang et al., 2004). Prior evidence linking first-trimester vaginal bleeding with risk for PTB may be potentially biased by subject selection (e.g. "
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    Full-text · Article · Nov 2011 · Human Reproduction
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    • "This bleed occurs at the time of the formation of the membranes and can lead to a complete miscarriage if the hematoma extends into the definitive placenta (Johns et al., 2003). Very early (in the first 8 weeks) vaginal bleeding is not associated with subsequent pregnancy complications, whereas the formation of an intrauterine hematoma at 13–14 weeks increases the risk of preeclampsia (Harville et al., 2003). The presence of a haematoma may also be associated with a chronic inflammatory reaction in the decidua resulting in persistent myometrial activity and expulsion of the pregnancy or progressive cellular dysfunction and/or damage to cellular layers of the membranes leading to pre-term rupture and delivery (Silver et al., 2005). "
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