What is the cause of a left upper side pinching or tugging feeling during In Vitro Fertilization (IVF) treatment?

Left Upper Side Pinching/Tugging Sensation During IVF Treatment

The left upper side pinching or tugging sensation during IVF treatment is most likely related to ovarian enlargement and follicular development from controlled ovarian stimulation, or potentially represents a corpus luteum cyst in early pregnancy following embryo transfer.

Primary Causes Related to IVF Process

Ovarian Stimulation Effects

• Ovarian hyperstimulation causes follicular enlargement that can produce localized discomfort, including pinching or tugging sensations, particularly if the left ovary is positioned higher or more laterally in the pelvis 1, 2.
• The standard IVF protocol requires 10-14 days of FSH-based ovarian stimulation starting from menses, during which multiple follicles develop simultaneously 1, 2.
• This follicular growth stretches the ovarian capsule and surrounding peritoneum, creating sensations of pressure, fullness, or sharp intermittent discomfort 1.

Post-Retrieval and Early Pregnancy Considerations

• If the sensation occurs after embryo transfer and pregnancy is achieved, a corpus luteum cyst (<3 cm) on the left ovary is the most likely explanation 3.
• The corpus luteum produces progesterone critical for early pregnancy support for 6-8 weeks until placental steroidogenesis takes over at 8-10 weeks gestation 3.
• Corpus luteum cysts can cause localized sharp or tugging sensations, particularly with position changes or physical activity 3.

Serious Complications to Exclude

Ovarian Hyperstimulation Syndrome (OHSS)

• While less common with modern protocols, OHSS can present with abdominal discomfort and represents a potentially serious complication 2, 4.
• Patients with thrombophilia (including antiphospholipid antibodies) have increased risk of severe OHSS 2.
• Upper extremity or neck symptoms weeks after OHSS resolution may indicate thromboembolic complications, though these typically present with swelling and pain rather than isolated pinching sensations 4.

Fluid Accumulation

• Uterine cavity fluid accumulation occurs in 4.7% of IVF cycles and is more common with tubal disease (8% versus 3.3% in non-tubal factors) 5.
• While this primarily affects implantation rates rather than causing symptoms, significant fluid can occasionally cause discomfort 5.

Clinical Approach

Immediate Assessment

• Perform transvaginal ultrasound to evaluate ovarian size, presence of corpus luteum, free fluid, and exclude complications 6, 3.
• Document the timing relative to stimulation phase, oocyte retrieval, or embryo transfer 1, 2.
• Assess for signs of OHSS: rapid weight gain, severe abdominal distension, nausea, vomiting, or decreased urine output 2, 4.

Management Based on Timing

• Pre-retrieval discomfort: Typically benign and related to normal follicular development; reassurance is appropriate if ultrasound shows expected ovarian response without complications 1.
• Post-transfer symptoms: If pregnancy is confirmed, corpus luteum visualization on ultrasound confirms the likely source; symptoms typically resolve as placental function increases after 8-10 weeks 3.
• Persistent or worsening symptoms: Warrant evaluation for OHSS, ovarian torsion (though this presents more acutely), or other complications 2, 4.

Important Caveats

• Left-sided symptoms are not inherently more concerning than right-sided, but unilateral symptoms warrant ultrasound evaluation to assess the specific ovary 6.
• Patients on anticoagulation (such as those with antiphospholipid antibodies receiving prophylactic LMWH during stimulation) should be evaluated for bleeding complications if pain is severe or associated with other symptoms 6, 2.
• The sensation should not be confused with cardiac symptoms; however, if accompanied by chest pain, shortness of breath, or arm radiation, cardiac evaluation is warranted given the rare association of thromboembolic events with IVF 4.