Multiple births after IVF could be harmful for the mother. Conceiving and giving birth to multiple babies via in vitro fertilization (IVF) treatment can place moms at greater risks of developing breast cancer, researchers say.
IVF is an artificial method known as Assisted Reproductive Technology (ART) adopted by people who experience difficulties in conceiving naturally. It is the process of manually combining an egg and sperm in a laboratory. Multiple pregnancies are very common in in vitro fertilization (IVF) treatment.
Dr Els Groeneveld from the VU University Medical Centre of Amsterdam, and colleagues, included 19,861 women who had undergone IVF treatments in Netherlands, between 1983 and 1995. Participants were selected from the Dutch Omega Study.
Nearly 12,590 women filled questionnaires and provided information about their IVF treatment. Of the total participants, about 1,688 had multiple births and 6,027 had a single baby. Nearly 4,874 had failed to conceive after the IVF treatments and were childless.
All the women underwent breast cancer tests. Nearly 317 of the participants were diagnosed with breast cancer- 57 women from the 1,688 multiple birth group, 155 from the 6,027 singleton group and 105 from the 4,874 childless group.
The findings presented at the annual meeting of The European Society of Human Reproduction and Embryology (ESHRE), July 9 claimed that mothers who had multiple IVF babies than those who had a single baby via IVF were at 44 percent higher risks of breast cancer.
The high levels of estrogen and progesterone, produced as part of the multiple pregnancies, play an important role in this occurrence, researchers explained.
"It has been generally assumed that increased levels of estrogen and progesterone in multiple pregnancies stimulate cellular proliferation in the breast, which increases accumulation of somatic mutations during cell division and leads to the development of breast cancer. Thus, breast cancer could be seen as a consequence of the multiple pregnancy itself," Dr Groeneveld, said in a news release.
However, according to the authors of the study, the risks were prevalent only in multiple pregnancies after complete implantation of embryos than multiple pregnancies achieved after an incomplete implantation.
Experts added that high embryo implantation potential (achieved when the mother naturally processes high concentrations of a protein known as vascular endothelial growth factor or VEGF) may also be contributing largely to this occurrence. The protein has long been known to have a role in breast cancer progression.
"In our study women who developed a multiple pregnancy from all transferred embryos represent women with high embryo implantation potential, possibly through increased levels of VEGF," Dr Groeneveld, explained. "So the main message of our study is that the increased breast cancer risk is not only a consequence of the multiple pregnancy itself because of high hormone levels, but that the risk of breast cancer may already be elevated prior to conception in women who have the potential-the 'maternal trait'-to develop a multiple pregnancy from all transferred embryos."
