What could be causing a 22-year-old female with a history of infertility, taking letrozole (letrozole) 7.5mg from cycle day 3 to 7, a left upper side pinching or tugging feeling at 8 days post-ovulation on cycle day 22?

Understanding Your Left Upper Side Sensation at 8 Days Post-Ovulation

The pinching or tugging sensation you're experiencing on your left upper side at 8 days post-ovulation (cycle day 22) is most likely related to normal post-ovulatory changes, including corpus luteum activity, early implantation sensations if conception occurred, or gastrointestinal factors—none of which are concerning at this stage. 1

What's Happening in Your Cycle Right Now

At 8 days post-ovulation with letrozole 7.5mg (cycle days 3-7), you are in the mid-luteal phase where several normal physiological processes occur:

• Ovulation timing with letrozole: You likely ovulated around cycle days 14-16 (approximately 7-9 days after your last letrozole pill on day 7), which places you at 8 days post-ovulation on cycle day 22 1
• Corpus luteum activity: After ovulation, the follicle that released the egg transforms into a corpus luteum, which produces progesterone and can cause localized sensations, mild cramping, or tugging feelings 1
• Potential implantation window: If conception occurred, implantation typically happens 6-12 days post-ovulation, so you're within this timeframe where some women report mild cramping or pinching sensations 1

Why Letrozole at 7.5mg?

Your dose represents the maximum recommended escalation for ovulation induction:

• Standard protocol: Letrozole starts at 2.5mg daily for 5 days (cycle days 3-7), with dose escalation up to 7.5mg in subsequent cycles for inadequate response 1
• Higher doses: The 7.5mg dose produces significantly more follicles (particularly >18mm) but doesn't necessarily improve pregnancy rates compared to 2.5mg 2
• Your response: Since you're on 7.5mg, this suggests you may have had inadequate follicular response to lower doses in previous cycles 1

What This Sensation Likely Represents

Most probable explanations (in order of likelihood):

1. Normal luteal phase changes: The corpus luteum on your left ovary (where you ovulated) is actively producing hormones and can cause localized sensations 1

2. Potential implantation: If conception occurred, implantation-related cramping or tugging is common and typically mild 1

3. Gastrointestinal factors: The "upper" location you describe could be bowel-related, as progesterone in the luteal phase slows gastrointestinal motility 1

4. Ovarian activity: With letrozole at 7.5mg, you may have developed 1-2 dominant follicles, and residual follicular activity or a small amount of free fluid post-ovulation can cause sensations 3

When to Be Concerned vs. Reassured

Reassuring features (what you likely have):

• Mild, intermittent pinching or tugging sensation
• No associated heavy bleeding
• No fever or systemic symptoms
• Localized to one side (consistent with unilateral ovulation)

Warning signs requiring immediate evaluation (seek care if you develop):

• Severe, sharp, or worsening pain: Could indicate ovarian torsion or ruptured cyst 4
• Heavy vaginal bleeding: More than normal menstrual flow 4
• Dizziness, fainting, or shoulder pain: Could indicate internal bleeding from ruptured ectopic pregnancy (though extremely unlikely at 8 DPO) 4
• Fever or chills: Could indicate infection 4

What to Do Next

Immediate management:

• Continue normal activities: This sensation alone doesn't require intervention 1
• Monitor symptoms: Note if pain worsens, changes character, or new symptoms develop 4
• Avoid premature testing: It's too early for reliable pregnancy testing; wait until at least 12-14 days post-ovulation (around cycle day 26-28) 1

Follow-up considerations:

• If you don't conceive this cycle: Discuss with your provider whether to continue letrozole at 7.5mg or consider adding intrauterine insemination (IUI), as ACOG recommends adding IUI after 3-6 cycles of letrozole alone 1
• Ultrasound monitoring: For future cycles, ensure ultrasound monitoring is performed to confirm appropriate follicular development and reduce multiple pregnancy risk, which is approximately 6% with 2 dominant follicles at your dose 3

Important Context About Your Treatment

Safety profile of letrozole:

• Pregnancy outcomes: Multiple studies show no increased risk of congenital malformations (2.15% rate, similar to natural conception) or pregnancy loss with letrozole compared to clomiphene 5
• Effectiveness: Letrozole is superior to clomiphene for ovulation induction in treatment-naïve PCOS women, with higher clinical pregnancy (38.5% vs 22.0%) and live birth rates (30.3% vs 18.9%) 6

Multiple pregnancy risk at your dose:

• With 7.5mg letrozole, you likely developed 1-2 dominant follicles 2
• Twin risk with 2 dominant follicles is approximately 6% 3
• This is significantly lower than gonadotropin stimulation, which produces multiple follicles 3

Bottom Line

The sensation you're experiencing is most likely benign and related to normal post-ovulatory physiology. Continue monitoring, avoid premature pregnancy testing, and contact your provider only if you develop warning signs listed above. Your current cycle timing and symptoms are entirely consistent with normal letrozole-induced ovulation at 8 days post-ovulation.