Infertility Treatments and Miscarriage?
Assisted Reproductive Treatments Not Shown To Increase Miscarriages
May 2, 2003 -- Women who undergo assisted reproductive treatments, such as in vitro fertilization, have no greater risk of miscarriages than women who conceive naturally, a new report shows.
It's been a worry for women, the possibility that assisted reproductive technologies (ART) could cause more miscarriages (or what's called spontaneous abortions) than natural conception -- as some reports have suggested.
In this new study, a group of epidemiologists looks at data from the U.S. Assisted Reproductive Technology Registry, which includes information on almost 64,000 pregnancies that resulted from ART procedures done between 1996 and 1998. They compared miscarriage rates for these ART pregnancies with those from the National Survey of Family Growth, a U.S. survey of women between the ages of 15-44.
"These findings suggest that [ART] does not pose a risk for spontaneous abortion," writes lead researcher Laura A. Schieve, PhD, with the Center for Disease Control and Prevention in Atlanta. Her study appears in the May 2003 edition of Obstetrics and Gynecology.
In fact, the miscarriage rate for all pregnancies was 15%, she reports. The rate varied greatly depending on the source of the egg -- whether the embryos were freshly fertilized or had been frozen and thawed, and the patient's age.
Among pregnancies that had been conceived using the patient's own eggs and freshly fertilized embryos, an increase in miscarriage rate occurred in relation to the mother's age, beginning in the early 30s. This trend became more marked from the mid-30s onward, writes Schieve.
In contrast, the mother's age played little role in miscarriage rate among pregnancies that were conceived using donor eggs and freshly fertilized embryos.
Among women in their 20s who conceived with their own eggs and freshly fertilized embryos, there was a 10% miscarriage rate. The rates were more than tripled for women in their 40s, reports Schieve.
For those pregnancies conceived with donor eggs and freshly fertilized embryos, the miscarriage rate was 13%, with little difference among age groups.
Miscarriage rates were higher overall among pregnancies conceived with frozen and thawed embryos, compared to those using freshly fertilized embryos. A trend of increasing risk with increased age was observed for pregnancies conceived with the patient's own eggs -- however, it was much less pronounced.
Single pregnancies had a higher miscarriage rate than twin or other multiple pregnancies, she reports.
Also, miscarriage rates were higher among women who had previously miscarried and among those who had undergone ART before.
Nevertheless, the ART pregnancies had a similar miscarriage rate as with other pregnancies in the population, the report states.
"The findings should reassure women undergoing [ ART] that their risk for a spontaneous abortion does not appear to be increased; however, older women using their own eggs still need to consider that their risk is quite high, even if not increased in comparison with women who conceive spontaneously," Schieve writes.
SOURCE: May 2003 Obstetrics and Gynecology.