Delivering Heavy Babies Can Double Mother's Risk of Breast Cancer
A latest research has associated delivering a heavy baby with the mother's risk of developing breast cancer later in life.
According to the study from the University of Texas Medical Branch at Galveston the chances of a woman contracting breast cancer, post delivery of a high birth weight baby doubles up. The researchers explain that carrying a large infant requires such a hormonal environment which favors future breast cancer development and progression.
The research finding may pave for prediction and prevention of breast cancer decades before its onset.
"We also found that women delivering large babies - those in the top quintile of this study, which included babies whose weight was 8.25 or more pounds - have increased levels of hormones that create a 'pro-carcinogenic environment.' This means that they have high levels of estrogen, low levels of anti-estrogen and the presence of free insulin-like growth factors associated with breast cancer development and progression," said lead author Dr. Radek Bukowski, professor of obstetrics and gynecology in the Division of Maternal-Fetal Medicine in a news release.
"Women can't alter their pregnancy hormones, but can take steps to increase their general protection against breast cancer." Dr. Bukowski added, further noting that breastfeeding, having more than one child, exercising and eating healthy are known to reduce the risk of the disease.
The research finding is further evidence to the fact that the weight of a woman herself and the weight of the baby at birth, both are linked to breast cancer. This, however is the first study that explores the risk involved in each factor.
According to Medical Express, Dr. Bukowski's team examined two cohorts of women from distinct data sets:
The Framingham Offspring Birth History Study, which has studied generations of women via medical examinations and laboratory assessments. Dr. Bukowski's team studied 410 women from this study, observed between 1991-2008, and maternal birth weight, infant birth weight and results of later examinations (e.g., breast cancer diagnosis) to determine breast cancer risk. The researchers also looked at data from the study on known breast cancer risk factors, such as age, race/ethnicity, body mass index, diabetes, use of hormone replacement therapy and maternal history of the disease, among others.
The First and Second Trimester Evaluation of Risk for Aneuploidy (FASTER) trial, which examined pregnancy hormones in nearly 24,000 women at 15 U.S. clinical centers between 1999 and 2003. The study included assessments of the hormones that affect infant birth weight and breast cancer risk - estriol (E3), anti-estrogen alpha-fetoprotein (AFP) and pregnancy-associated plasma protein-A (PAPP-A).
It seems, around 7.6 percent of the women from the Framingham cohort in this study were later diagnosed with breast cancer. The risk of breast cancer in mothers with heavier babies was found to be more than double when compared to others.
Also, the risk of cancer due to heavy baby birth weight was independent of other cancer risk factors including mother's weight at the time of the delivery.
"Recent animal studies have suggested that breast stem cells, which are involved in the origins of breast cancer, may increase or decrease their number in response to hormone exposures, including ones during pregnancy," added Dr. Bukowski.
"They retain a 'memory' of prior hormone exposure, which could explain the increased risk of breast cancer seen following pregnancy, especially in women with a large birth weight infant. The hormones create a long term effect that may lead to breast cancer later."
One drawback of the story is that the associations made by the study between large infants' birth weight and breast cancer risk and between infants' birth weight and hormonal environment during pregnancy were tested in different populations of women.
Thus, there needs to b further research conducted to determine how exactly the concentrations of pregnancy hormones mediates the relationship between large infant birth weight and breast cancer.
The study was published in the July 17 issue of PLoS ONE.