1st Trimester Bleeding
Any bleeding during the first trimester of pregnancy is abnormal.
The cause may be trivial or serious, but it is always abnormal.
Bleeding during the first trimester is common. At least one-third of all pregnant women will experience some degree of bleeding (perhaps only light spotting) during this time. Half of those will ultimately lose the pregnancy, while the other half will continue their pregnancy normally and without any further problems.
Clinical evaluation of women with first trimester bleeding involves looking for evidence of:
- Inevitable abortion
- Incomplete abortion
- Ectopic pregnancy
- Gestational trophoblastic disease
- Other miscellaneous causes for bleeding, including cervical/vaginal trauma, infection, and polyps
- Depending on the clinical circumstances, evaluation may include a history, physical exam, and such laboratory tests as ultrasound, quantitative HCG, and progesterone.
Abortion
Loss of a pregnancy during the first 20 weeks of pregnancy, at a time that the fetus cannot survive. Such a loss may be involuntary (a “spontaneous” abortion), or it may be voluntary (“induced” or “elective” abortion).
Miscarriage is the layman’s term for spontaneous abortion, an unexpected 1st trimester pregnancy loss. Since the term “spontaneous abortion” may be misunderstood by laymen, the word “miscarriage” is sometimes substituted.
Abortions are further categorized according to their degree of completion. These categories include:
Such losses are common, occurring in about one out of every 6 pregnancies.
For the most part, these losses are unpredictable and unpreventable. About 2/3 are caused by chromosome abnormalities incompatible with life. About 30% are caused by placental malformations and are similarly not treatable. The remaining miscarriages are caused by miscellaneous factors but are not usually associated with:
- Minor trauma
- Intercourse
- Medication
- Too much activity
Following a miscarriage, the chance of having another miscarriage with the next pregnancy is about 1 in 6. Following two miscarriages in a row, the odds of having a miscarriage with the next pregnancy is still about 1 in 6. After three consecutive miscarriages, the risk of having a fourth is greater than 1 in 6, but not very much greater.