P-597 Pain intensity of oocyte retrieval of low and moderate number of oocytes is only mild, questioning the need of anesthesia and analgesia
Authors: Von Wolff M , Popovici R , Boogen E , Eisenhardt S , Huober-Zeeb C , Nordin M , Siercks I , Roumet M , Magaton I 
Published: July 2024

Study question

What is the pain intensity of oocyte retrieval (oocyte pick-up, OPU) without anesthesia and analgesia in women with low or medium number of follicles?

Summary answer

Pain intensity is only mild and is only slightly different in cycles with up to 5 aspirated oocytes and in repeated In-Vitro-Fertilisation (IVF) cycles.

What is known already

OPU is usually performed with anesthesia. However, OPU with anesthesia requires more treatment time and is more expensive. Previous studies have assessed the pain of OPUs without anesthesia in conventionally stimulated IVF using 15 to 19 gauge (G) aspiration needles and found high pain scores. Therefore, anesthesia is usually used in such IVF treatments. In contrast, in Natural cycle IVF (NC-IVF) OPU is commonly performed without anesthesia. The pain intensity of such OPUs and of OPUs of medium number of follicles has never been systematically analysed.

Study design, size, duration

A prospective, cross-sectional, multi-center observational study analyzing IVF cycles without anesthesia and analgesia was performed in seven IVF centers in Germany and Switzerland between January 2022 and March 2023. Women who performed one to ten NC-IVF or minimal stimulation IVF treatment cycles were enrolled. 518 aspirations were performed with 17G needles and 1772 with 19G or 20G needles. In total, 2290 cycles from 1039 patients were recorded.

Participants/materials, setting, methods

Pain score was assessed using a Visual Analogue Scale (VAS), graded 0 to 10 (0 = no pain; 10 = worst pain possible). Information about ovarian stimulation, number of collected oocytes, needle size, aspiration pressure and complications were recorded. A descriptive analysis was performed first, followed by a statistical evaluation using a linear mixed model to analyze the effect of the number of oocytes retrieved and of the number of cycles on the pain score.

Main results and the role of chance

The number of oocytes retrieved varied from 0 to 16 (interquartile range 1-2). The pain score varied from 0 to 10 with a median pain score of 3.0 (interquartile range 2-4), defined as “mild” pain. Compared to a reference value of aspirations with 1 oocyte, the pain score increased slightly by 0.5 points if no oocyte was retrieved, by 0.42 points if 2-5 oocytes were retrieved and by 1.14 points if ≥ 6 oocytes were retrieved (p &lt; 0.001). Pain decreased slightly with repeated aspirations (-0.05 points per cycle) (p = 0.028). Needle size did not affect the pain scores. Seventeen vaginal and abdominal bleedings were recorded, two requiring hospitalization (&lt;0.1%).

Limitations, reasons for caution

As only NC-IVF and minimal stimulation IVF cycles were analysed using mainly 19G and 20G needles, the results cannot be extrapolated to cycles with a high ovarian response and to aspirations using larger volume needles.

Wider implications of the findings

In case of one or few follicles OPU can be offered without anesthesia and analgesia to reduce aspiration time and cost.

Trial registration number

NCT05125497