(RxWiki News) If you're trying to have a baby with fertility treatments, there's no reason to skip your morning cup of coffee...but keep the refills to a minimum.
A recent unpublished study presented at a fertility conference has found that downing more than five cups of coffee a day can cut women's chances of having a baby with in vitro fertilization in half.
"Limit your coffee intake during IVF and fertility treatments."
In a study led by Dr. Ulrik Schiøler Kesmodel, of the Fertility Clinic of Aarhus University Hospital in Denmark, researchers tracked 3,959 women undergoing cycles of in vitro fertilization (IVF) and intracytoplasmic sperm injection (ICSI).
IVF means an egg is fertilized by sperm outside of the body, such as in a petri dish, and is commonly called making a "test tube baby." ICSI is a type of IVF procedure in which one sperm is directly injected into an egg outside the body.
The researchers gathered information about how many cups of coffee the women drank daily at the start of their fertility treatment and then during follow-up cycles.
Their calculations took into account the woman's age, reason for needing treatment, weight, whether she smoked, how much alcohol she drank, how many embryos were taken from her ovaries and her dosage of follicle-stimulating hormone (FSH), a hormone given to women undergoing fertility treatments to stimulate the release of eggs.
The results revealed that drinking more than five cups of coffee a day reduced the pregnancy rate among the women by 50 percent.
This rate is similar to the rate of decreased IVF success among women who smoke, the researchers noted.
"Although we were not surprised that coffee consumption appears to affect pregnancy rates in IVF, we were surprised at the magnitude of the effect," said Dr. Kesmodel.
Their calculations did not show any negative effects in IVF success among women drinking between one and five cups a day.
"There is limited evidence about coffee in the literature, so we would not wish to worry IVF patients unnecessarily," said Dr. Kesmodel. "But it does seem reasonable, based on our results and the evidence we have about coffee consumption during pregnancy, that women should not drink more than five cups of coffee a day when having IVF."
He added that women should not be concerned about having a small to moderate amount of coffee each day.
"The fact that we found no harmful effects of coffee at lower levels of intake is well in line with previous studies on time-to-pregnancy and miscarriage, which also suggest that, if coffee does have a clinically relevant effect, it is likely to be upwards from a level of four-to-six cups a day," he said.
The study was presented July 3 at the 28th annual meeting of the European Society of Human Reproduction and Embryology in Istanbul.
Because the study has not yet been published in a peer-reviewed journal, its results should be regarded as preliminary and still require review by researchers in the field. No information was available regarding funding or disclosures.