August 10, 2011 ( –  While use of the birth control pill raises the risk of deadly blood clots by 500 percent, the risk shoots to over 1,700 percent for U.S. women with a common vein malformation, California researchers have found.

In the study published by the American Journal of Obstetrics and Gynecology, Stanford University School of Medicine’s Dr. Lawrence Hofmann and his team noted that up to 25 percent of the population has a vein malformation or narrowing, known as stenosis, in the left common iliac vein.

Comparing 35 women with deep vein thrombosis (DVT), a blood clot that is potentially fatal, against 35 women without the condition, the Stanford group found the risk of DVT in women with a 70 percent venous stenosis who also use combined-oral contraceptives (COC) – containing both the hormones estrogen and progestin –  to be nearly 18 times greater. This finding compares with a risk 3.5 times for women with venous stenosis and 5 times for women with COC-use.

The study drew its conclusion using computed tomography (CT) or magnetic resonance imaging (MRI) scans to evaluate women with DVT, and comparing the women to an equal number of women of the same age who came to the emergency room with abdominal pain.

The researchers noted that about 1 to 3 young women among every 10,000 who are not taking oral contraceptives will develop DVT every year. That risk is 6 times greater for young women who take the Pill for a year.

According to Reuters, approximately 12 million women in the U.S. use the COC form of birth control pill.

The California researchers recommended further studies to investigate their conclusion and its potential clinical implications. 

Commenting on the Stanford study, National Catholic Bioethics Center Director of Education Father Tadeusz Pacholczyk told LifeSiteNews, “I knew a pharmacologist who was fond of reminding his students: ‘no drug has just one effect.’ The contraceptive Pill exemplifies this.”

“Medicine is oriented towards restoring lost or compromised function,” Father Pacholczyk said. “The Pill, when used for contraceptive purposes, does not constitute medicine in the proper sense of the term; it rather represents a decision on the part of the medical community to collude with a patient population in pursuing non-medical ends and morally problematic lifestyle agendas that threaten marriage, fidelity, and the chastity of young people.”