Causes of Miscarriage at 7 Weeks Gestation
Miscarriage before 13 completed weeks is classified as early pregnancy loss. [1] Most 7-week losses occur due to nonviable embryonic development, most commonly from fetal chromosomal abnormalities. [1], [2] Fetal chromosomal abnormalities are reported in about half of all early pregnancy losses. [2]
Primary Etiology: Fetal Chromosomal Abnormalities
Fetal chromosomal abnormalities are the most common cause of early pregnancy loss. [1] Chromosomal abnormalities account for more than two-thirds of early pregnancy loss between 6 and 10 weeks of gestation. [3]
Uterine Structural and Anatomic Factors
Congenital uterine anomalies and acquired uterine abnormalities are associated with increased risk of early pregnancy loss. [3] Leiomyomas and intrauterine adhesions are examples of uterine factors that increase risk. [3]
Antiphospholipid Syndrome
Antiphospholipid syndrome is the thrombophilia consistently associated with early pregnancy loss. [2]
Maternal Endocrine and Systemic Conditions
Some maternal medical conditions are associated with increased risk of early pregnancy loss. [3] Diabetes, hyperthyroidism, and lupus are specifically listed as risk-associated conditions. [3]
Infections and Other Contributing Exposures
Certain exposures during pregnancy that may harm fetal development are associated with increased risk of early pregnancy loss. [3] Some infections are included among exposures linked to increased risk. [3] Examples of environmental exposures associated with increased risk include lead, mercury, and radiation. [3] Alcohol exposure is listed among exposures associated with increased risk. [3]
Not Supported Causes
Working, exercising, stress, arguments, having sex, and having used birth control pills before getting pregnant are not causes of miscarriage. [1]
Clinical Notes for a 7-Week Presentation
Ectopic pregnancy and molar pregnancy can present with bleeding or cramping in early pregnancy and require exclusion before labeling the event as miscarriage. [5] Gestational trophoblastic disease is another early-pregnancy condition that requires clinical evaluation. [5]
Practical Clinical Implication
At 7 weeks, an explanation-focused workup is most likely to identify fetal chromosomal abnormalities, with additional maternal and uterine factors considered based on clinical context. [1], [2], [3] If pregnancy loss is recurrent rather than sporadic, broader evaluation is typically considered under recurrent pregnancy loss guidance. [4]