You may have come to know that drugs (medications prescribed) including OCs are classified in ‘generations’. Changes to the structure and content of medications go thru ‘improvements’ usually based on scientific research findings – some good some bad! So now we are on the fourth generation of birth control pills (OCs), NOW made with anti-androgenic progestin.
The ECG (also known as the EKG) is a tracing of the electrical impulse that tells heart muscle at different milliseconds to contract or relax. We have learned that the earlier formulations of OCs had a greater negative effect on electrical disruption of the critical ‘QT interval'(QTc) – time to conduct within the heart important contraction function. Having a prolonged QTc is a well-known marker for an increased risk of sudden cardiac death. A heart just stops and death! Research has shown in the past that our natural hormones effect this critical timing – testosterone and progesterone shorten QTc, while estrogen prolongs it.
Yes normal is dependent on age, sex, however generally accepted is: Normal =430msec in males, 450msec in females. Borderline =431-450msec in males, 451-470msec in females. What is considered Abnormal is > 450 msec in males and > 470msec in females.
Northern California Kaiser Permanente*, in a ‘look back’, studied 410,782 women (ages 15-53) from 1/95 through 6/08 to find the relationship between oral contraceptive use, the type of oral contraceptive, and QTc of their hearts. Yes they did ECGs and measured carefully!
They found using fourth-generation OCs results in a 2-millisecond prolonging of QTc. This in theory can further be increased if the woman was on certain other medications. Examples include: an anthracycline antibiotic (antitumor antibiotics)or Erythromycin. Also antihistamines (astemizole, diphenhydramine, hydroxyzine, loratidine, mizollastine to name a few).
Carefully consider the side effects for all prescription and over the counter drugs before taking them. some individuals are born with a prolong QTc and many athletic programs require an ECG before participation.
*Sedlak T, et al “Oral contraceptive use and corrected QT interval: Evidence of an adverse effect” Ann Noninvasive Electrocardiol 2013; DOI: 10.1111/anec.12050.