Among twin and triplet pregnancies that were reduced to singleton or twin pregnancies, there was a substantial reduction in complications such as preterm birth and very preterm birth, according to new research published in CMAJ (Canadian Medical Association Journal).
Although rates of death and serious illness were not lower among all multifetal pregnancies that were reduced, pregnancies that resulted from fertility treatments did show a significant reduction in rates of death or serious illness following fetal reduction.
Multiple births of twins and triplets -- and the associated health risks -- have increased in many high-income countries, with a respective twofold and threefold increase in recent decades. In Canada, triplet births or higher have increased from 52.2 per 100 000 live births to 83.5 between 1991 and 2009, mainly because of an increase in fertility treatments for older women of child-bearing age.
In this study of all births -- live births and stillbirths -- in British Columbia (BC) between 2009 and 2013, researchers looked at birth outcomes among women who underwent elective fetal reduction of multifetal pregnancy compared with multifetal pregnancies without such reduction. Among the 208 827 women who gave birth during the study period, 95 (0.04%) underwent fetal reduction, with 45 women delivering twins and 50 delivering singletons.
Dr. Neda Razaz, lead author of the study, noted that "The fetal reduction-associated decrease in preterm birth and low birth weight overall, combined with the decrease in death and serious illness among babies of women who conceived following fertility treatments, suggests that fetal reduction in multifetal pregnancy offers substantial benefits."
Women who underwent fetal reduction were more likely to be older and of a higher socioeconomic status and significantly more likely (75% compared with 3.3%) to have undergone fertility treatment.
The authors note that they had limited details on the timing, reason and number of fetuses reduced in some pregnancies. They note that physicians need to be sensitive when discussing the risks and benefits of fetal reduction with parents. "Clinicians counselling women with multifetal pregnancy should be aware of the potential for substantial parental stress resulting from fetal reduction procedures, including negative feelings such as guilt, regret and grief," the authors conclude.
The study was conducted by researchers from the University of British Columbia and BC Women's Hospital and Health Centre, Vancouver, BC; Karolinska Institutet, Stockholm, Sweden; and Hadassah Medical Centre, Jerusalem, Israel.