Maternal factors

General factors:

• 10% due to maternal illness e.g. pyrexia
• chromosomal e.g. balanced translocation. In cases of recurrent abortion, 5 - 10% of couples will have a chromosomal abnormality in one partner.
• hypertension - the risk of abortion is increased among chronic hypertensives and reduced if this is controlled.
• systemic lupus erythematous
• thyroid dysfunction
• infections e.g. TORCH
• smoking
• alcohol

Local factors:

• cervical incompetence
• uterine abnormalities

There is evidence that higher maternal age is associated with an increased risk of spontaneous abortion (1).

Reference:

• (1) Machonochie N et al. Risk factors for first trimester miscarriage--results from a UK-population-based case-control study. BJOG. 2007;114(2):170-86