Lipid and biochemical changes after low-dose oral contraception

Area of Science:

• Endocrinology
• Pharmacology
• Metabolic Medicine

Background:

• Combined oral contraceptives (COCs) are widely used for family planning.
• Understanding the metabolic effects of low-dose COCs is crucial for patient safety and informed prescribing.
• Previous studies have shown mixed results regarding the metabolic impact of different COC formulations.

Purpose of the Study:

• To evaluate and compare the metabolic effects of two low-dose combined oral contraceptives (norethisterone/ethinyl estradiol and levonorgestrel/ethinyl estradiol) versus intrauterine devices (IUDs) in Singaporean women.
• To assess changes in glucose metabolism, lipid profiles, and liver function parameters.

Main Methods:

• A randomized, double-blind study involving 58 women allocated to either NET/EE (n=29) or LNG/EE (n=29) COCs, and 23 women using IUDs as controls.
• Blood samples were collected at baseline, 3 months, and 12 months for metabolic parameter analysis.
• Key parameters included fasting and 2-hour glucose, triglycerides, total cholesterol, HDL, LDL, and liver function tests.

Main Results:

• The NET/EE group showed decreased fasting glucose and increased 2-hour glucose and triglycerides. The LNG/EE group had increased 2-hour glucose and decreased LDL cholesterol and total cholesterol at specific time points.
• Both COC groups experienced suppressed alkaline phosphatase, bilirubin, and SGOT. NET/EE also significantly suppressed albumin.
• Metabolic changes, except for 2-hour glucose, were not significantly different between COC groups and the IUD control group, with many liver function parameters showing improvement.

Conclusions:

• Low-dose COCs, NET/EE and LNG/EE, induce some metabolic alterations, particularly in glucose metabolism.
• Most observed metabolic changes, including lipid profiles and liver function, were not clinically significant when compared to IUD use.
• Except for potential glucose intolerance, the metabolic profile changes associated with these COCs are generally considered safe.