Differential Diagnosis for First Trimester Bleeding in Pregnant Patient
Single Most Likely Diagnosis
- Miscarriage (Spontaneous Abortion): This is the most common cause of first trimester bleeding, accounting for approximately 50% of cases. It is often due to chromosomal abnormalities in the fetus.
Other Likely Diagnoses
- Ectopic Pregnancy: Although less common than miscarriage, ectopic pregnancy is a significant concern due to its potential for severe morbidity and mortality. Risk factors include previous ectopic pregnancy, pelvic inflammatory disease, and assisted reproductive technology.
- Threatened Abortion: Vaginal bleeding with a closed cervix and a viable fetus. The pregnancy may continue normally, but there is a higher risk of miscarriage.
- Implantation Bleeding: Light bleeding or spotting that occurs when the embryo implants in the uterus, usually around 6-12 days after fertilization.
Do Not Miss Diagnoses
- Molar Pregnancy: A rare condition where the placenta becomes abnormal and can cause severe bleeding, preeclampsia, and other complications. It requires prompt diagnosis and treatment to prevent serious health issues.
- Placenta Previa: A condition where the placenta covers the cervix, which can cause severe bleeding, especially in the second and third trimesters, but can occasionally present in the first trimester.
- Uterine Rupture: Although extremely rare in the first trimester, uterine rupture can occur in women with a history of uterine surgery, such as a cesarean section.
Rare Diagnoses
- Cervical Polyps or Cancer: Bleeding can be caused by cervical polyps or cancer, although these are rare causes of first trimester bleeding.
- Vaginal or Urethral Trauma: Trauma to the vagina or urethra can cause bleeding, but this is not typically related to the pregnancy itself.
- Coagulopathy: Bleeding disorders, such as von Willebrand disease or thrombocytopenia, can increase the risk of bleeding during pregnancy.
Workup and Treatment
The workup for first trimester bleeding typically includes:
- Ultrasound: To confirm the location and viability of the pregnancy.
- Blood tests: To check for pregnancy hormone levels (β-hCG) and to assess for anemia or coagulopathy.
- Pelvic exam: To assess for cervical dilation, bleeding, or other abnormalities.
Treatment depends on the underlying cause:
- Miscarriage: May require dilation and curettage (D&C) or medical management with misoprostol.
- Ectopic Pregnancy: Requires prompt surgical or medical intervention to prevent rupture and severe bleeding.
- Threatened Abortion: Typically managed expectantly, with bed rest and close monitoring.
- Implantation Bleeding: Usually requires no treatment other than reassurance.
Each case should be individualized based on the patient's specific presentation, medical history, and preferences.