The Canadian Perinatal Surveillance System reports that this dramatic decline in stillbirths since 1928 may be attributed to several factors, including improvements in community health practices such as better nutrition and sanitation, and improvements in maternal health and education. Other studies cite factors such as advances in medical surveillance, more accessible health care and optimal intervals between pregnancies, aided by the widespread use of contraceptives. Stillbirth rates are substantially more frequent for older women - 11.2 per 1,000 among women aged 40 to 44 and 15.9 per 1,000 among those 45 and over. Women 20 to 34 had the lowest stillbirth rate, 5.3 for every 1,000 births of 20 or more weeks. The rate among teenage girls was slightly higher, 7.6 per 1,000 births.
Stillbirths are more likely to occur in a multiple-birth event.