A systematic review published in The Cochrane Library did not find compelling evidence to support the routine use of aspirin in women being treated for IVF. The researchers reported that taking aspirin during an IVF cycle did not seem to increase a woman's chances of becoming pregnant.
The use of aspirin during IVF treatment is controversial. Part of the thinking behind any potential benefit is that aspirin may improve the blood flow to the womb and ovaries. However, there are also concerns that taking aspirin may cause miscarriage or complications in pregnancy.
The latest review is an update of a Cochrane Systematic Review published in 2007. The researchers added evidence from new trials giving a total of 13 that together involved 2,653 women. All women were undergoing IVF and in most cases, aspirin was taken as a 100 mg dose once a day. Although one large study suggested some benefit associated with taking aspirin, the overall conclusion was that there was no evidence that aspirin would improve a woman's chances of conceiving compared to placebo. Large trials showing beneficial effects would now be needed to change these conclusions, according to the researchers.
"Couples undergoing IVF often feel so desperate that they are prepared to try anything that may improve their chances of conceiving," said lead researcher Charalambos Siristatidis of the Assisted Reproduction Unit at the University of Athens in Greece. "But given the current evidence, there is still no basis to recommend that women take aspirin to help them become pregnant."
The researchers had looked primarily for trials that used live births as a measure of effectiveness, but only three reported this information. Instead, most studies reported pregnancies and the number of women who became pregnant in the group given aspirin was about the same as in group given placebos. Five studies reported miscarriage rate and found no difference between those taking aspirin and those taking placebos.
"It was disappointing to see that so few of the studies reported live birth rate as this is ultimately the outcome all couples undergoing IVF are interested in," said Siristatidis. "The lack of information on miscarriage rate is also concerning given previous studies that have linked higher doses of aspirin to miscarriage."