Table 1 Characteristics of the included studies

Calabre 2020 [13]

Single France

252 randomized

252 analyzed

Inclusion criteria:

Age < 43 years

married or partnership > 2 years

produced < 5 follicles > 14 mm on triggering day under long or antagonist protocol

Exclusion criteria:

contraindication to oocyte puncture, oocyte donor, couples treated in viral programs, not speaking French, unable to provide informed consent, a lack of follicles on the day of triggering or patients who had oocyte retrieval at the weekend.

Study group (n=127):

The first follicle was aspirated using a 35 cm double-lumen 17-gauge needle and the fluid collected in a tube, after which the tube was changed to collect the flush out from this same follicle using a flushing medium once for each follicle.

Control group (n=125)

Puncture with 35 cm single-lumen 17-gauge needle. The follicular fluid were collected in tubes without differentiating between the follicles

Primary outcome:

No oocyte retrieved

No MII oocytes

Secondary outcomes:

fertilization rate

No embryos transferred

Clinical pregnancy rate

LBR Miscarriage rate

NCT 01329302

De Souza 2021 [14]

Single Brazil

208 randomized and analyzed

Inclusion criteria:

Age 34 -42 years

Poor responders

Exclusion criteria:

Study group (n= 105): 17-gauge double-lumen needles were used, half buffered medium was injected into each follicle, followed by a new aspiration, and the liquid up to 3 times

Control group (n=103): single-gauge 19-gauge needles

No of aspirated oocytes

No of MII oocytes

Capture failure rate

Oocyte/ follicle ratio

Not registered

Haines 1989 [15]

Single Australia

36 randomized and analyzed

Unclear inclusion and exclusion

Study group (n=18): A double lumen 17 G; 25 cm needle is used. If the oocyte was not recovered on the first aspirate, the follicle was then flushed and aspirated up to five times

Control group (n=18)

A single-lumen 17 G, 23.5 cm needle was allocated, each follicle was punctured and aspirated

Number of follicles

Not registered

Haydardedeoglu 2011 [16]

Single Turkey

274 randomized and analyzed

Inclusion criteria:

Women with normal ovarian response undergoing IVF

Exclusion criteria:

Poor responders

Women under microdose flare protocol

High responders as PCOS

Study group ( n=149): A 17-gauge needle was used to aspirate the follicles then 2 mL flush medium was reinjected and re-aspirated once for each punctured follicle

Control group ( n=125): ), a 17-gauge needle was used to aspirate the follicles

No oocyte retrieved

No MII oocytes

Duration of oocyte retrieval

Fertilization rate

No of embryos transferred

CPR

ChPR

LBR

Implantation rate

Cancellation rate

hospitalization

NCT 00995280

Haydardedeoglu 2011 [17]

Single Turkey

80 randomized and analyzed

Inclusion criteria:

Age 20-43 years

Poor responders

Exclusion criteria:

Natural IVF cycle

Monofollicular response

Endometrioma

Study group (n=40):

A 17-gauge needle was used to aspirate follicles then 2 mL of warmed (37°C) culture medium was injected into each follicle and re-aspirated and re-injected three times for each punctured follicle

Control group (n=40): a 17- gauge needle was used to aspirate follicles

Primary outcome:

No MII oocytes

Secondary outcomes

No retrieved oocytes

Fertilization rate

Implantation rate

Duration of procedure

CPR

LBR

NCT 02391155

Kara 2012 [18]

Single Turkey

200 randomized and analyzed

Inclusion criteria: women undergoing IVF using long protocol

Study group ( n=100): a double-lumen transvaginal oocyte retrieval needle was used to aspirate the follicles then each aspirated follicle was washed with 2 mL flush medium and re-aspirated

Control group ( n=100): a single-lumen transvaginal oocyte retrieval needle was used with a single follicle puncture

No retrieved oocytes

No MII oocytes

Time of procedure

Fertilization rate

Cancellation rate

CPR

OPR

No registration

Kingsland 1991 [19]

Single UK

34 randomized and analyzed

Inclusion criteria:

Age ≤ 35 years

Tubal infertility

Exclusion criteria:

Study group (n=18): a JP6L double channeled needle was used for follicle aspiration and then flushing with 10 ml of Earle's balanced salt solution

Control group (n=16): a JP6L double channeled needle was used for follicle aspiration

No oocyte retrieved

Duration of procedure

Fertilization rate

CPR

OPR

No registration

Lainas 2023 [20]

Single Greece

210 randomized and analyzed

Inclusion criteria

Age <43 years

BMI 18-35 kg/m2

Women underwent ovarian stimulation for ICSI

Exclusion criteria:

Single ovary

Ovarian pathology

Use of IVF for fertilization

Study group (n=105): A 16G double lumen was used to aspirate the follicles

Control group (n=105):

A 16G double lumen was used to aspirate the follicles if a COC was not retrieved in the initial aspirate, follicular flushing was performed until a COC was retrieved, up to a maximum of five times

Primary outcome: No of COCs

Secondary outcomes:

Oocyte recovery rate , oocyte maturation rate, fertilization rate , good quality embryos on Day 2 rate procedure time

NCT05473455

Levens 2009 [21]

Single USA

30 randomized and analyzed

Inclusion criteria:

Low ovarian response

Exclusion criteria:

Patients’ ineligible for transvaginal oocyte retrieval secondary to hyporesponse

Study group (n=15): a 35 cm 16-gauge double-lumen transvaginal oocyte retrieval needle was used to aspirate follicle then flushed once with 2 mL of sterile phosphate buffered saline

Control group (n=15): a 35 cm 16-gauge single-lumen transvaginal oocyte retrieval needle was used for follicle aspiration

Primary outcome:

No oocytes retrieved

Secondary outcomes:

recovery rate, total number of mature oocytes, maturity rate, fertilization rate, number of embryos transferred, implantation rate, on-going pregnancy rate, and retrieval time

No registration

Malhotra 2020 [22]

Single India

71 randomized and analyzed

Inclusion criteria:

Age 22-38 years

having 3–5 follicles ≥14 mm on the day of triggering

normal uterine cavities

Exclusion criteria:

endometrioma

Study group (n= 35):

A double lumen needle of 17-gauge was used to aspirate the follicles followed by 2 mL of flush with culture medium if no oocyte was retrieved at the direct aspiration up to 3 times

Control group (n=36): a single lumen needle of 17 gauge with a suction pressure of 100–110 mm Hg was used to aspirate the follicles

Primary outcome:

No oocytes retrieved

Secondary outcomes:

Time of anesthesia and procedure, fertilization rate, cleavage rate,

No of embryos, grade 1 embryos and embryos transferred, failed oocyte recovery, implantation rate, miscarriage rate.

CPR

LBR

CTRI/2017/07/009062

Méndez Lozano 2007 french

Sigle France

123 randomized and analyzed

Mok-Lin 2013 [23]

Single USA

50 randomized and analyzed

Inclusion criteria:

Poor responders

Exclusion criteria:

Patients without a planned, fresh embryo transfer, patients undergoing natural IVF and patients with canceled cycles

Women randomized in a previous cycle

Study group (n=25): each aspirated follicle was flushed up to four times using a manually pressed syringe with 5 ml of culture media warmed to 378C and re-aspirated using a 16-gauge double-lumen needle

Control group ( n=25): a 16-gauge single-lumen oocyte retrieval needle was used to aspirate the follicles with transvaginal ultrasound guidance

Primary outcome:

No retrieved oocytes

Secondary outcomes:

Time of anesthesia and procedure, No of mature oocytes,

No of embryos transferred implantation rate

CPR

LBR

NCT 01558141

Ronchetti 2023 [24]

Single

Italy

200 randomized and analyzed

Inclusion criteria:

Age 18 -42 years

Candidate for IVF or ICSI

Exclusion criteria: frozen pelvis from PID or endometrioma

Study group (n=100): a 17-gauge double-lumen needle was used to aspirate and flush the follicles twice

Control group (n=100): a 17-gauge Cook® Single Lumen Ovum Aspiration Needle was used to aspirate follicles

Primary outcome:

No oocytes retrieved

Secondary outcome:

No punctured follicles

Retrieved / triggered follicle ratio

Retrieval time

No MII oocytes

No embryos transferred

Complications

CPR

OPR

NCT03611907

Salman 2015 [25]

Single Egypt

185 randomized and analyzed

Inclusion criteria:

infertile women who underwent IVF/ICSI

Exclusion criteria: unclear

Study group (n=92): a 16-gauge double-way tap with (2 ml) injection of Earl's medium till oocyte retrieved or maximum two times

Control group (n=93): a 16-gauge single lumen needle used, with suction continue until a small amount of blood-stained fluid appeared in the tubing or flow stop

No retrieved oocytes

Operative time

No embryos transferred

CPR

ChPR

No registration

Schwartz 2020 [26]

Single Switzerland

164 randomized and analyzed

Inclusion criteria:

Age 18-42 years

Candidate for Gn free monofollicular IVF

Regular menstrual cycles

Exclusion criteria:

women with >2 previous embryo transfers without pregnancy, an LH surge on the trigger day, or previous enrolment in the current study

Study group (n=83): a 19-gauge single-lumen needles was used to aspirate the follicle then flush the follicles 5 times with a flushing medium containing heparin

Control group (n= 81): a 19-gauge single-lumen needle was used to aspirate the follicle

Primary outcome

No MII oocytes

Secondary outcomes:

No oocytes retrieved

No flushes

Fertilization rate

Transfer rate

Implantation rate

CPR

LBR

NCT 02641808

Scott 1989 [27]

Single USA

44 randomized and analyzed

Inclusion criteria: women underwent IVF

Exclusion criteria: unclear

Study group (n=22): aspirating the contents of the follicle and then injecting through the second port enough heparinized Delbecco's solution (1-3 ml) to reexpand the follicle. This volume was then aspirated back into the syringe. This lavage was performed one or more times until the oocyte was recovered or until the follicle

Control group ( n= 22): aspirate the follicle with a hand-held 20-ml syringe, remove the needle from the patient, and then aspirate an additional 2 ml of heparinized Delbecco's solution through the system to wash the fluid

In both groups the needle has an outer diameter of 1.5 mm and an inner diameter of 1.0 ram. With 4 shallow grooves. The DLN incorporates a needle-within-a-needle design

No of oocytes aspirated

No oocyte recovery

No registration

Tan 1992 [28]

Single UK

100

Inclusion criteria: women underwent IVF

Exclusion criteria: women developed >25 or <4 follicles wider than 14 mm diameter on the day of triggering

Study group (n=50): follicle aspiration using the JP6L double-channel needle, then flushing with 1.5 mL of media

Control group (n= 50): follicle aspiration using the JP6L double-channel needle, the inner channel of the needle was removed so that the needle was converted into a single-channel needle.

No aspirated follicles

No oocytes retrieved

Time od procedure

Fertilization rate

Oocyte recovery rate

O embryos transferred

CPR

No registration

Von horn 2017 [29]

Single Germany

80

Inclusion criteria:

Age 18-45 years

BMI 18-35 kg/m2

Had ≤ 5 follicles > 10 mm at the end of follicular phase in both ovaries

Candidate for IVF/ICSI

Exclusion criteria:

Women with 1 ovary

Difficulty puncturing one or both ovaries

Study group (n=40):

Follicles in both ovaries were to be aspirated by a17GSteiner-TanNeedle®withasuctionpressureof180mmHgand then flushed 3 times

Control group (n=40): all visible follicles in both ovaries were to be aspirated by the17 G Gynetics ® single-lumen needle with a suction pressure of 180 mmHg

Primary outcome: No of COC

Secondary outcomes:

Oocyte retrieval rate

No MII oocytes

No fertilized oocytes

Procedure time

OPR

Pain score

NCT02365350