What is the recommended start day for initiating hormonal contraceptives, such as combination oral contraceptives (COCs) like ethinyl estradiol and levonorgestrel, in relation to the first day of menses versus a Sunday start?

Initiating Hormonal Contraceptives: First Day of Menses vs. Sunday Start

Starting hormonal contraceptives within the first 5 days of the menstrual cycle (first day start) is recommended over Sunday start because it provides immediate contraceptive protection without requiring backup contraception. 1

Evidence-Based Recommendations

Timing of Initiation

• Combined hormonal contraceptives (CHCs) can be started at any time if pregnancy can be reasonably ruled out 1
• Starting options:
  • First day start: Begin on the first day of menstrual bleeding
  • Sunday start: Begin on the first Sunday after menstrual bleeding starts

Effectiveness and Protection

• First day start (within first 5 days of cycle):
  • Immediate contraceptive protection
  • No need for backup contraception 1
• Sunday start or starting >5 days after menses:
  • Requires 7 days of backup contraception (condoms or abstinence)
  • Higher risk of pregnancy during the first week 1, 2

Clinical Evidence

Research shows that pregnancy rates do not differ significantly by timing of CHC initiation, but follicular activity increases the later in the cycle CHCs are started 1. When COCs were started at a follicle diameter of 10mm (approximately cycle day 7.6), no ovulations occurred 3. However, with 20mcg ethinyl estradiol pills, starting on day 7 showed a significant increase in ovulation compared to starting on day 1 4.

Practical Algorithm for Initiation

1. Preferred approach: First day start (within first 5 days of menses)

   • Begin pills on first day of menstrual bleeding
   • No backup contraception needed
   • Maximizes immediate effectiveness

2. Alternative approach: Start any other time ("Quick Start")

   • Can begin immediately if reasonably certain patient is not pregnant
   • Requires 7 days of backup contraception
   • May improve initial access but doesn't improve long-term continuation 1, 5

3. Sunday start (if patient strongly prefers)

   • Begin on first Sunday after menstruation begins
   • Requires 7 days of backup contraception unless started within first 5 days of cycle
   • May help with weekend pill-taking routine 6

Special Situations

Postpartum (Not Breastfeeding)

• Wait until ≥21 days after delivery due to increased thrombosis risk 1, 2
• Need backup contraception for 7 days if menstrual cycles have returned and >5 days since bleeding started 1

Postabortion

• Can start within 7 days after abortion, including immediately post-procedure 1
• No backup needed if started at time of surgical abortion 1

Switching Methods

• Can start immediately if reasonably certain patient is not pregnant 1
• Need backup for 7 days if >5 days since menstrual bleeding started 1

Common Pitfalls to Avoid

1. Delaying initiation unnecessarily

   • Waiting for next menses creates unnecessary barriers and pregnancy risk 7
   • Evidence shows benefits of starting CHCs likely exceed risks even when pregnancy status is uncertain 1

2. Inadequate counseling about backup contraception

   • Failure to use backup for 7 days when starting mid-cycle is a common cause of contraceptive failure
   • Clear instructions about backup method are essential

3. Forgetting special considerations for low-dose formulations

   • 20mcg ethinyl estradiol pills may have higher ovulation rates when started on day 7 vs. day 1 4
   • Lower-dose formulations may require stricter adherence to timing recommendations

4. Overlooking required examinations

   • Blood pressure measurement is needed before CHC initiation 1
   • Other examinations or tests generally not required for healthy women

The evidence clearly supports first day start over Sunday start for maximizing immediate contraceptive effectiveness while minimizing the need for backup contraception.