Reproductive epidemiology

Vaginal bleeding in early pregnancy is not associated with a higher cancer risk compared with pregnancies in women from the general population of similar age.

We identified 105,277 women with threatened abortion (TA), with a median follow-up of 16.9 years (interquartile range 10.5-24.4 years). During the follow-up, 6,571 women with TA developed cancer. The standardised incidence ratio (SIR) for any cancer was 1.01 (95% CI=0.98-1.03). TA was not associated with an increased risk of cancer of breast (SIR=1.02, 95% CI=0.98-1.07), uterine cervix (SIR=0.93, 95% CI=0.83-1.03), ovary (SIR=0.91, 95% CI=0.78-1.06); or uterus (SIR=0.79, 95% CI=0.66-0.95). TA is not associated with an increased risk of cancer diagnosis.

Abstract The objective of the study was to investigate an association between TA and the woman’s subsequent increased risk of cancer. We conducted a nationwide cohort study of 105,277 women with a first-time threatened abortion (TA) diagnosis in Denmark (1978-2013) with up to 33 years of follow-up.