Oral contraceptive regimens where estrogen and progestin levels fluctuate throughout the cycle are categorized as:

• A. Monophasic
• B. Biphasic
• C. Triphasic
• D. Quadriphasic

Answer: (D)

Oral contraceptive regimens that feature fluctuating estrogen and progestin levels throughout the cycle are classified as quadriphasic. This categorization stems from the design of these contraceptives, which typically contain varying doses of hormones at four distinct phases over a menstrual cycle. The primary objective of this approach is to mimic the natural hormonal fluctuations of a menstrual cycle while also maintaining effective contraception.

In contrast, monophasic regimens provide a constant dose of hormones throughout the cycle, whereas biphasic and triphasic systems include two and three different hormone dose levels, respectively. Quadriphasic regimens enable more tailored hormone delivery, potentially resulting in fewer side effects and improved menstrual regulation for some users.

By offering this multi-phase approach, quadriphasic formulations can address individual hormonal needs more precisely compared to other regimens that do not account for such variability.