Combined contraceptive pill and obesity

Obesity and combined oral contraceptive pill

• if BMI is >= 35 kg/m2 the risks associated with use of CHC generally outweigh the benefits (1)

Combined hormonal contraception (CHC)

• most evidence suggests that effectiveness of combined oral contraception (COC) is not affected by body weight or BMI

• limited evidence suggests a possible reduction in patch effectiveness in women weighing >=90 kg
  
  
• limited evidence suggests that effectiveness of the vaginal ring is not affected by body weight or BMI
  
  
• combined hormonal contraception (CHC) use is UKMEC 2 for use by women with BMI >= 30-34 kg/m2 and UKMEC 3 for women with BMI >=35 kg/m2

Weight gain with CHC

In the general population there is no evidence that use of CHC causes weight gain. There is no specific evidence relating to weight gain with CHC use by women who are overweight or women with obesity

FSRH state (1):

• women with obesity should be informed that:
  • risk of thrombosis increases with increasing BMI
  • current CHC use is associated with increased risk of VTE
  • current CHC use is associated with a small increased risk of myocardial infarction and ischaemic stroke
  • if BMI is >= 35 kg/m2 the risks associated with use of CHC generally outweigh the benefits

Reference:

1. FSRH (April 2019). Overweight, Obesity & Contraception
2. Gallo MF, Lopez LM, Grimes DA, Schulz KF, Helmerhorst FM. Combination contraceptives: effects on weight.Cochrane Database Syst Rev. 2008 Oct 8;(4):CD003987.