March 7, 2006

Infertility type may raise ectopic pregnancy risk

NEW YORK (Reuters Health) - Infertility due to
abnormalities of the fallopian tube or uterus raises the risk
that in vitro fertilization or other assisted reproductive
techniques (ART) will result in an "ectopic" pregnancy, one in
which the fertilized egg attaches itself outside the normal
uterus location, new research shows.

Ectopic pregnancies typically occur in the fallopian tubes,
thus they're sometimes called "tubal pregnancies." Outside of
the uterus, the fetus is unable to grow properly and may
actually rupture the fallopian tube, an event that can be fatal
for the mother. Early ectopic pregnancies are often treated
with drugs to dissolve the fertilized egg, whereas later on,
surgical removal of the abnormal pregnancy is often required.

To investigate factors associated with ectopic pregnancy
risk with ART, Dr. Laura A. Schieve, from the Centers for
Disease Control and Prevention in Atlanta, and her associates
analyzed outcomes reported to the CDC's ART Registry between
1999 and 2001.

Of the 94,118 pregnancies included in the registry, 2.1
percent were ectopic. The investigators note that the rate is
2.0 percent in the general population.

Tubal and uterine abnormalities raised the risk of ectopic
pregnancy by 38 to 168 percent, the report in the journal
Obstetrics and Gynecology indicates.

Transfer of a fertilized egg into the fallopian tubes, an
ART procedure known as "ZIFT," increased the risk of ectopic
pregnancy by 75 percent. The risk also rose when three or more
embryos were implanted into the mother.

"Maternal age, prior spontaneous abortions, use of (other
types of ART) were not significant predictors of ectopic
pregnancy," the authors note.

"As new technologies in ART become available, their
potential impact on ectopic pregnancy should be investigated,"
Schieve and her associates conclude.

SOURCE: Obstetrics and Gynecology, March 2006.