In a nutshell
This analysis examined the effects of different assisted reproductive techniques on birth outcomes.
For women and men with fertility issues, assisted conception techniques can be the only path to pregnancy. Techniques such as intrauterine insemination, or IUI (when semen is inserted directly into the uterus), in vitro fertilization, or IVF (when the egg and sperm are combined outside of the body and the embryo is placed into the uterus), and intracytoplasmic sperm injection, or ICSI (when the sperm is inserted directly into the egg prior to in vitro fertilization), can greatly increase the odds of pregnancy. However, fertility treatments have also been associated with negative outcomes, including low birth weight, preterm delivery (delivery before the due date), and various birth defects. The majority of research into these potential outcomes generally does separate the different methods of reproductive assistance in the analyses. The current analysis explored the role of treatment method on negative outcomes in both single and twin births.
Methods & findings
The records of 306,965 births over 16 years were included in this analysis. Of these, 2% were due to assisted conception techniques. Of the 98% that were spontaneous conceptions, less than 1% were in women with known fertility issues or who had previously used an assisted reproductive technique. Assisted conception techniques included IUI, IVF using either fresh (implanted within 5 days of egg extraction) or frozen embryos, and ICSI using fresh or frozen embryos. Outcomes measured included stillbirths, birth weights, delivery timing, size at birth, and infant death after birth.
Stillbirth was twice as likely to occur following assisted conception compared to spontaneous conception, particularly in patients using IVF or ICSI with fresh embryos. Overall, infants born following assisted conception were twice as likely to be born before their due dates, were three times as likely to have very low birth weights, and post-birth mortality was twice as likely compared to spontaneous conceptions.
Compared to spontaneous conception, the risk of post-birth mortality, as well as very low birth weight, was 5 times more likely following IVF using fresh embryos. Low birth weight was twice as likely following ICSI using fresh embryos, as well. While the risks of these negative effects were reduced by using frozen embryos, this raised the risk of high birth weights by 36%. Twins conceived with assisted conception techniques were also more likely to have low birth weights.
The bottom line
This analysis concluded that assisted conception techniques are associated with multiple negative birth outcomes, particularly in vitro fertilization and intrcytoplasmic sperm injection using fresh embryos. These risks, however, can be reduced with the use frozen embryos.
The fine print
This was a retrospective study (it looks back at patients who have been treated in the past). These studies are known to have lower statistical power than studies directly testing a hypothesis. This study also included very small numbers of women who received these fertility treatments compared to women who did not undergo treatments. Further studies using larger numbers of women should be done to fully determine the rates of these negative outcomes. Finally, the study did not report on other health issues the women included may have been facing, which could have affected the rates of negative outcomes.
Published By :
Jan 08, 2014