Historical Development
Early Devices: Made from inert materials like silkworm gut.
Lippes Loop (1960s): Double 'S'-shaped plastic device for better retention.
Copper IUDs (1970s): Leveraged copper's spermicidal properties.
Hormonal IUDs: Released progestins (e.g., levonorgestrel) for contraception and therapeutic benefits.
Types of IUDs
Copper IUDs:
Mechanism: Copper ions create a toxic uterine environment for sperm and ova.
Example: ParaGard (effective up to 10 years).
Hormonal IUDs:
Mechanism: Release levonorgestrel to thicken cervical mucus, inhibit sperm, and prevent endometrial growth.
Examples: Mirena, Skyla, Liletta, Kyleena (3–7 years).
Design and Development Considerations of Intrauterine Devices
Material Selection:
Biocompatible materials like polyethylene, sometimes combined with barium sulfate for X-ray visibility.
Shape and Size:
Optimized to fit the uterine cavity comfortably, reducing irritation and risk of expulsion.
Drug Release Kinetics:
Controlled-release mechanisms ensure consistent therapeutic levels over the intended duration.
Insertion Devices:
Designed for ease of use, ensuring patient comfort and minimizing insertion-related discomfort.