Multiple Births and Fertility Treatments

MedicalResearch.com Interview with:
Aniket D. Kulkarni, M.B., B.S., M.P.H
Women’s Health and Fertility Branch
Centers for Disease Control and Prevention
Atlanta, Georgia

MedicalResearch.com: What are the main findings of the study?

Dr. Kulkarni: Our study estimates the contribution of fertility treatments and natural conception to multiple births. Fertility treatments include IVF and non-IVF treatments. Non-IVF treatments primarily include ovulation induction and ovarian stimulation coupled with timed intercourse or intrauterine insemination (IUI). All estimated proportions were adjusted for maternal age which makes this study unique.

The incidence of twin births nearly doubled and the incidence of triplet and higher-order births quadrupled over the last 4 decades.

Our study estimates that by 2011, a total of 36% of twin births and 77% of triplet and higher-order births resulted from conception assisted by fertility treatments, after adjusting for maternal age.

After initial increase, the incidence of triplet and higher order births decreased by 29% from 1998 to 2011. The decrease in triplet and higher order births has coincided with a 70% reduction in the transfer of 3 or more embryos during IVF and a 33% decrease in the proportion of triplet and higher order births attributable to IVF. The decline in the number of embryos transferred during IVF became possible due to monitoring of ART treatments and outcomes and the work of professional societies, which have repeatedly revised practice guidelines to include recommendations for lowering the number of embryos transferred.

In contrast, non-IVF fertility treatments of ovulation induction and ovarian stimulation are estimated to contribute the increasing number of multiple births. Hence there is a need for surveillance of births from non-IVF fertility treatments.

MedicalResearch.com: Were any of the findings unexpected?

Dr. Kulkarni: This study shows trends over the last 15 years of the effect of fertility treatments on multiple births.  The findings show that a lot of progress has been made by reducing the number of embryos transferred during IVF treatments although there is a room for improvement by increasing single embryo transfers.  Non-IVF treatments have been previously shown to be significant contributors to multiple births and this study reinforces those findings along with giving maternal age adjusted estimates.

MedicalResearch.com: What should clinicians and patients take away from your report?

Dr. Kulkarni: If considering fertility treatment, understand the potential risk of multiple births. The risk of multiples due to IVF can be greatly minimized by transferring just one embryo. It is much more difficult to prevent multiple births resulting from ovulation induction and ovarian stimulation because of unpredictable ovarian follicular growth dynamics.

MedicalResearch.com: What recommendations do you have for future research as a result of this study?

Dr. Kulkarni: We need better understanding of the use of non-IVF fertility treatments in the United States (types of treatments, their effectiveness and safety). Consideration should be given to establishing a national registry collecting data on non-IVF fertility treatments. It would be useful to estimate the contribution of fertility treatments and natural conception to multiple births by state.

Citation:

Fertility Treatments and Multiple Births in the United States

Aniket D. Kulkarni, M.B., B.S., M.P.H., Denise J. Jamieson, M.D., M.P.H., Howard W. Jones, Jr., M.D., Dmitry M. Kissin, M.D., M.P.H., Maria F. Gallo, Ph.D., Maurizio Macaluso, M.D., Dr.P.H., and Eli Y. Adashi, M.D.

N Engl J Med 2013; 369:2218-2225
December 5, 2013
DOI: 10.1056/NEJMoa1301467