VANCOUVER — Better prenatal diagnostic methods have led to more terminations of fetuses with congenital abnormalities, the reason why overall stillbirth rates in B.C. have risen by about a third in the past decade, a newly published study shows.
The overall B.C. stillbirth rate rose from 8.08 per 1,000 births in 2000 to 10.55 per 1,000 in 2010. Stillbirths are defined as the loss — spontaneously or through abortion — of a fetus after 20 weeks, or the loss of a fetus weighing 500 grams.
Before that gestational age, or under that weight, “miscarriage” is the term used to describe pregnancy loss. Statistics on miscarriages are not recorded.
There were 461,083 live births in B.C. during the decade beginning in 2000, and 3,991 stillbirths, a number that has risen because of an increase in therapeutic abortions.
There has been a 137 per cent increase in such pregnancy terminations in the past decade — from 2.4 per 1,000 births in 2000 to 5.7 per 1,000 a decade later.
The increase has meant fewer births of babies with severe congenital anomalies, a B.C. study in the Canadian Medical Association Journal shows.
“The rate of congenital anomalies among live-born infants decreased from 5.21 per 100 births in 2000-2002 to 4.77 per 100 in 2008-2010,” the study reports.
On the other hand, the rate of spontaneous stillbirths, in which babies die in utero, decreased slightly, according to the research led by Dr. K.S. Joseph, who has dual appointments at the University of B.C. department of obstetrics and gynecology and the School of Population and Public Health.
Joseph said that while the increase in stillbirths may seem like a “disquieting trend,” the study shows that there is a good explanation for it since it is due to positive developments in prenatal monitoring.
Hundreds of congenital malformations can lead to abortions or spontaneous stillbirths, and Joseph said only about five per cent of all congenital anomalies lead to pregnancy termination, including those involving severe chromosomal defects, fetuses missing critical organs like brains, those with incurable central nervous system diseases or severe cardiovascular malformations.
He said previous research has shown that miscarriages are largely due to fetal abnormalities, while spontaneous stillbirths result from maternal and/or fetal complications that arise during pregnancy.
Most pregnancy terminations in the study occurred between 20 and 23 weeks’ gestation, following prenatal diagnosis methods such as ultrasounds and blood testing.
Besides showing the increase in stillbirth rates stemming from pregnancy terminations, the study draws attention to the emotional duress experienced by women and their families who have suffered through stillbirth.
Joseph said the harm could be mitigated if B.C. changed the requirement for registering a stillbirth.
He said stillbirth registrations should be filled out by health providers, instead of by grieving parents.
“Legal requirements for stillbirth registration add unnecessary stress to grieving parents and should be revamped,” said co-author Cheryl Davies, vice-president of ambulatory programs at B.C. Women’s Hospital and Health Centre.
