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measurement of ovarian size has been shown to decrease in
women aged 40 years and older and may be an earlier indicator
of menopausal status than menstrual history.[25–28] A correlation between ovarian volume and reproductive outcome in IVF
cycles has been shown [27], and this test is inexpensive and relatively easy to perform, with minimal intra- and interobserver
variations. [25]
Antral follicle count (AFC), defined as the number of follicles 10 mm or less in diameter detected by ultrasound in the
early follicularphase ofthe menstrual cycle, is another parameter
found to correlate with age.[29] A recent meta-analysis comparing basal FSHlevelsand AFC revealed that AFCis more predictive
of ovarian response to infertility treatments [17] and an estimate
of the size of the cohort of follicles available for stimulation in
a given cycle may be made. A normal basal antral follicle count
(BAF) between 8 and 18 typically will produce 8 to 20 oocytes
at the time of retrieval following intermediate-dose stimulation
with 225 to 300 IU of gonadotropin in women under 35 years of
age. For women over 35, consideration for receiving 450 IU of
gonadotropin may be given based on their age.
Patients with a high BAF (≥18) tend to have a polycystic
ovary–like appearance with multiple follicles in the periphery
of the ovary with an exaggerated stromal component. Low-dose
stimulation following GnRH agonistdown-regulationistypically
chosen and carefully monitored by serial ultrasound and estradiol levels to decrease the risk of severe ovarian hyperstimulation
syndrome. Patient with alow BAF (≤8)tendto be low responders
who areresistant to stimulation and require more aggressive protocols. These patients will benefitfrom avoiding oversuppression
of the pituitary gland as well as use of 450 IU of gonadotropin
per day during the stimulation phase.
Stimulation of multiple follicle growth can induce a premature LH surgein the absenceof strategies tosuppress the pituitary
gonadotrope. Before theavailability of GnRHanalogues, as many
as one in seven cycles was canceled because of premature ovulation. Desensitization of gonadotrope is typically accomplished
by administering GnRH analogues starting up to 10 days preceding the intended stimulation.[30] The GnRH agonist downregulation is sometimes associated with failureto respond to subsequent stimulation with gonadotropins. This may occur even in
women who have regular cycles on their own and are receiving supraphysiologic doses of gonadotropin. Women who are at
highest risk for poor responsesubsequenttoGnRHagonistdownregulation of gonadotrope are those who have low BAF counts,
havea history ofpoorresponsivenesstogonadotropin,aregreater
or equal to 40 years of age, and have unexplained infertility. In
such patients, alternative stimulation using GnRH antagonists
or GnRH agonist flare cycles may be used. GnRH antagonists
became clinically available in 1999 and are now widely used for
stimulation protocols. Asthe gonadotropes are not suppressed at
the onset of ovarian stimulation, patients typically receive similar or lower doses of gonadotropins. The GnRH antagonist is
administered when the leading follicle size reaches 12 to 14 mm,
at whichpoint an LH-containinggonadotropin or low-dose hCG
is supplemented in addition to the gonadotropin doses.
Another alternative protocol that allows prevention of premature LH surge is the use of microdose GnRH analogues to
induce endogenous gonadotropin flare to augment the exogenous gonadotropin doses.[31] Premature LH surges have been
reported but are very rare. Ovarian stimulation is followed by
serial ultrasounds and estradiol levels, initially after 4 days of
stimulation and then every 1 to 2 days until at least two follicles
reach 16 to 18 mm in average diameter. hCG 5000 or 10,000 IU
is administered 35 hours before the transvaginal oocyte retrieval
schedule.
TRANSVAGINAL OOCYTE
RETRIEVAL PROCEDURE
Proper room and equipment setup is crucial for successful
recovery of oocytes with high fertilization and development
potential.
Room Setup
An ambulatory suite is useful for this procedure. Equipment
includes an operating table with lithotomy position, an ultrasound machine (Figure 7.3.1) with a transvaginal transducer and
needle guide (Figure 7.3.2), heating blocks, test tubes (Figure
7.3.3), a syringe with a blunt needle, a single- or double-lumen
echo-tipped 16- to 18-gauge needle (Figure 7.3.4), a suction
pump, anesthetic equipment (Figure 7.3.5), and a well-equipped
IVF lab (Figures 7.3.6, 7.3.7). The ultrasound transducer is typically of highfrequency (6.5 MHz) andthe endovaginal probe may
be equipped with a needle guide for the oocyte retrieval. The IVF
lab should be in close proximity to the procedure room (Figure
7.3.8), which will prevent the adverse effects of room temperature on the oocytes. The temperature of the heating block and all
the lab tables are set up at 37
◦
C. If there is no heating block available in the operating room, retrieval should be done as quickly as
an embryologist can examine the specimens. During eggretrieval,
follicular aspirates and all flushes are maintained at 37
◦
C ± 0.5◦C
and a pH of 7.4 ± 0.1.
Vacuum and Needle Setup
Two different types of needles (single- and double-lumen)
are available (Figure 7.3.4) with sufficient diameter (16- to
18-gauge) to prevent cumulous oophorous disruption during
aspiration.[32] If flushing is done, a double-lumen needle is
preferred.[33,34] Needles are echo-tipped and as a result are
readily visualized with ultrasound during aspiration. Recovery
rate and quality of the oocytes areinfluenced by the suction pressure applied to the needle. A negative pressure between 100 and
120 mm Hg is applied to the needle at the instant of follicular
puncture and stopped after needle withdrawal. Higher pressures
may lead to damaged and fractured oocytes.[33,34]
Anesthesia
Transvaginalultrasound–guidedoocyte retrieval istypically done
as an outpatient procedure under conscious sedation. Patients
need to have fasted for at least 6 hours before the procedure. A
combination of hypnotics suchas propofol ora sedative hypnotic
such as midazolam and/or intravenous (IV) opioids are used to
achieve adequate relaxation and anesthesia. Multiple studiesindicate asteady rise in the level of anesthetic agents in follicular fluid
shortly after starting the procedure. The effect of these anesthetics on oocyte fertilization is not clear, but some report dose- and
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Figure 7.3.1. An operating table with lithotomy position and ultrasound with a transvaginal transducer.
Figure 7.3.2. Transvaginal transducer and needle guide and probe cover.
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Figure 7.3.3. Heating blocks and test tubes.
Figure 7.3.4. Single- (upper) and double-lumen needle (lower).
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Figure 7.3.5. Anesthetic equipment.
Figure 7.3.6. IVF lab: microscopes. All the tables are set at 37◦C.
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Figure 7.3.7. IVF lab: microinjection device.
Figure 7.3.8. The IVF lab should to be in close proximity to the operating room. Notice the window.
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time-dependent decreases in fertilization rate.[35,36,37] In general, it is prudent to minimize anesthesia exposure, but the duration of the procedure may vary from 10 to 30 minutes depending
on the operator’s skill, number of follicles, evacuation pressure
set up, and the flushing technology.
Procedure Description
The patient is placed in the dorsal lithotomy position and after
achieving sufficient sedation, the vagina is prepared either with
saline lavage alone or a wash with an antiseptic cleanser. If Betadine (Purdue) is used, the vagina should be irrigated copiously
with normal saline to minimize oocyte toxicity. Today, most centers use normal saline alone, and there appears to be no increase
in postprocedure infection [38], particularly when a prophylactic antibiotic such as doxycycline is used around the time of the
procedure. A high-frequency endovaginal probe covered with a
conducting jelly and a sterile latex cover orcondom is introduced
into the vagina with its affixed needle guide (Figure 7.3.2). The
ovaries are located, and each follicle is in turn aligned with the
puncture line on the monitor. The needle is inserted into the
closest follicle in the plane of its largest diameter visualized by
ultrasound. The tip of the aspirating needle is then advancedinto
the center of the follicle along the shortest path. As negative pressure is applied, collapse of the follicle is readily visualized and the
needle tip may be manipulated to curette the follicle. The follicular content iscollectedin a tubeand transferred toa heating block
maintained at 37
◦
C until the assistant hand delivers the sample
to the embryologist in the adjoining IVF laboratory. If all the follicles in each ovary can be aspirated through a single puncture
site, the numberof separate needle puncturesthrough the vaginal
wall and into the ovary will be minimized. Care must be taken
to identify the location of hypogastric vessels to prevent inadvertent puncture and serious intra-abdominal bleeding. When
the needle is withdrawn from one ovary, it should be flushed
with culture medium to clear any retained oocytes from the line.
During the procedure, if the aspirates are found not to contain
oocytes by the embryologist, or if the patient has only a few follicles, flushing may maximize the oocyterecoveryrate and absolute
number of oocytes. The use of flushing during oocyte retrieval,
however, is somewhat controversial. Multiple follicle flushes are
time-consuming procedures,and several prospectivestudies have
reported possible detrimental effects of flushing on oocyte quality and fertilization rates.[33,34] If flushing is done, the number
of flushings should be limited to two (4 mL). Flushing may be
done with two types of media, a commercially available prepared
media or heparinized buffered saline prepared by the embryologist. No difference in oocyte recovery, fertilization, or cleavage
rate between the two flushing media has been found.[39]
Transvaginal ultrasound–guided oocyte retrieval has a number of advantagesover the laparoscopic approach: (1) oocytescan
be recovered in case of severe pelvic adhesions, (2) general anesthesia is not necessary, (3) transvaginal follicular puncture has
lower potential morbidity, (4) the operative and recovery times
are reduced, and (5) oocytes are not exposed to carbon dioxide
pneumoperitoneum, which may acidify thefollicular fluid. Complications from the oocyte retrieval procedure include infection,
bleeding, and trauma to the adjacent organs. According to some
reports, the incidence of postprocedure infection ranges from
0.2% to 0.58%, including a high rate of tubo-ovarian abscess for-
mation in up to 0.24% of the cases.[40–42] Abscess formation
occurs between 1 and 6 weeks following retrieval. Predisposing
factors for infection include a past history of pelvic inflammatory disease, puncture of an endometriotic cyst, puncture of
the hydrosalpinx, and incidental bowel penetration during egg
recovery. Puncture of an endometriotic cyst, in particular, may
be associated with chemical peritonitis or postoperative abscess
formation.[43,44] To reduce these risks, the cyst should be irrigated with the flushing media and intraoperative prophylactic IV
antibiotics are recommended. The endometrioma contents are
also considered to be toxic to the oocytes, and care must be taken
to flush the needles and use new Petri dishes in the lab. Any pelvic
infections post retrieval will likely lead to a lower implantation
rate.[42]
Multiple puncture sites in the vaginal vault and/or inappropriate handling of the vaginal probe will increase the risk of
bleeding. The risk of vaginal bleeding has been reported to be
as high as 0.09%.[45,47] Bleeding from the vaginal puncture site
frequently will stop with pressure applied to the site with the
vaginal probe during the procedure. Rarely, there is a need to
suture the puncture sites after withdrawing the needle at the end
of the procedure. Aspiration of blood from the needle signifies
injury to the follicular wall or ovarian blood vessels. Keeping the
needle in the center of the follicle minimizes injury to the follicular wall. If a retroperitoneal hematoma or internal bleeding is
suspected, observation with pelvic ultrasound to ascertain persistent bleeding should be done after the procedure and prompt
intervention and emergency laparotomy should be done to prevent significant blood loss. Ultrasound-guided oocyte retrieval
is rarely associated with injury to neighboring organs, such as
the bladder, intestines, ureters, and appendix. Although anesthetic complications are also rare, vagovagal reaction leading
to severe bradycardia and cardiac arrhythmia and asystole following deep abdominal pressure on very high ovaries has been
reported.[45]
Embryo Transfer
Embryos are transferred in most centers at either the third or
fifth day after oocyte retrieval, depending on theexperience of the
embryology lab. The placement of the embryos into the endometrial cavity is a critical step that affects the overall success. Echotip Teflon-coated embryo transfer catheters have permitted optimization of this step under abdominal ultrasound guidance.[48]
A trial of mapping for determining the optimal technique for
intrauterine catheter placement notedin the cyclebeforethestimulation would allow smooth embryo transfer.
Luteal Support
Oocyte retrieval by aspiration of follicles also results in removal
of a substantial portion of the granulosa cells. Combined with
suppression of the gonadotropes, some patients will have greatly
reduced progesterone production in the luteal phase. Luteal support should be done with either exogenous progesterone or additional hCG injections during the luteal phase. Several formulations of progesterone are commercially available: intramuscular
progesterone in oil, vaginal micronized progesterone capsules,
vaginal suppositories, and vaginal gel. Studies comparing them
havenotfound anytobe superior over others [49], butnoneofthe
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studies has been large enough to have sufficient power. Progesterone supplementation is continued until the luteal–placental
shift that occurs during the 10th to 12th weeks of gestational
age.
REFERENCES
1. Steptoe PC, Edwards RG. Birth after re-implantation of a human
embryo. Lancet . 1978;2:366.
2. Centers for Disease Control and Prevention. 2003 Assisted Reproductive Technology Success Report. Available at: http://www.cdc.
gov/ART/ART2003/nation.htm.
3. Heape W. Preliminary note on the transplantation and growth
of mammalian ova within a uterine foster mother. Proc R Soc.
1890;48:457–458.
4. Iwamatsu T, Chang MC. In vitro fertilization of mouse eggs in the
presence of bovine follicular fluid. Nature. 1969;224:919–920.
5. Edwards RG. Maturation in vitro of human ovarian oocytes.
Lancet. 1965;ii:926–929.
6. Edwards RG, Donahue RP, Baramki TA, Jones HW. Preliminary
attempts to fertilize human oocyte matured in vitro. AmJObstet
Gynecol. 1966;96:192.
7. Steptoe PC, Edwards RG. Laparoscopic recovering of preovulatory human oocytes after priming of ovaries with gonadotropins.
Lancet. 1970; ii:683–689.
8. Lopata A, Johnstone IWH, Leeton JF, Muchnicki D, Talbot TM,
Wood C. Collection of human oocytes at laparoscopy and laparotomy. Fertil Steril. 1974;25:1030.
9. Lenz S, Lauritsen JG, Kjellow M. Collection of oocytes for IVF by
ultrasonically guided follicular puncture. Lancet. 1981;1:1163.
10. Robertson R, Picker R, O’Neill C, Ferrier A, Saunders D. An experience of laparoscopic and trans-vesicle oocyte retrievals in an IVF
program. Fertil Steril. 1986;45:88.
11. Gleicher N, Friberg J, Fullan N, et al. Egg retrieval for in-vitro
fertilization by sonographically controlled vaginal culdocentesis.
Lancet. 1983;2:508.
12. Russell J, Decherney AH, Hobbins J. A new trans-vaginal probe
and biopsy guide for oocyte retrieval. Fertil Steril. 1987;47:350.
13. Lavy G, Restropo-Candelo J, Diamond M, Shapiro B, Grumbeld
L, DecherneyAH. Laparoscopic and transvaginal ova recovery: the
effect on ova quality. Fertil Steril. 1988;49:1002.
14. Marrs R. Does the method of oocyte collection have a major influence on IVF? Fertil Steril. 1986;46:193.
15. Scott RT Jr, Hofmann GE. Prognostic assessment of ovarian
reserve. Fertil Steril. 1995;63:1–11.
16. Bancsi LF, Broekmans FJ, Mol BW, Habema JD, te Velde ER. Performance of basalfollicle-stimulatinghormoneinthepredictionof
poor ovarian response and failure to become pregnant after in vitro
fertilization: a meta-analysis. Fertil Steril. 2003;79:1091–1100.
17. Hendriks DJ, Mol BW, Bancsi LF, te Velde ER, Broekmans FJ.
Antral follicle count in the prediction of poor ovarian response
and pregnancy afterinvitro fertilization; ameta-analysisand comparison with basal follicle-stimulating hormone level. Fertil Steril.
2005;83:291–301.
18. Lockwood GM,Mutuukrishna S,LedgerWL.Inhibinsandactivins
in human ovulation, conception and pregnancy. Hum Reprod
Update. 1998;4:284–295.
19. Klein NA, Illingworth PJ, Groome NP, McNeilly AS, Battaglia DE,
Soules MR. Decreased inhibin B secretion is associated with the
monotropic FSH rise in older, ovulatory women: a study of serum
and follicular fluidlevelsofdimericinhibinAandBin spontaneous
menstrual cycles. J Clin Endocrinol Metab. 1996;81:2742–2745.
20. Muttukrishna S,Child T,LockwoodGM,GroomeNP,BarlowDH,
Ledger WL. Serum concentrations of dimeric inhibins, activin A,
gonadotrophins and ovarian steroids during the menstrual cycle
in older women. Hum Reprod. 2000;15:549–556.
21. Seifer DB, Scott RT Jr, Bergh PA, et al. Women with declining
ovarian reserve may demonstrate adecreasein day 3 seruminhibin
B before a rise in day 3 follicle-stimulating hormone. Fertil Steril.
1999;72:63–65.
22. Durlinger AL, Visser JA, Themmen AP. Regulation of ovarian function: the role of anti-Mullerian hormone. Reproduction.
2002;124:601–609.
23. de Vet A, Laven JS, de Jong FH, Themmen AP, Fauser BC. Antimullerian hormone serum levels: a putative marker for ovarian
aging. Fertil Steril. 2002;77:357–362.
24. Cook CL, Siow Y, Taylor S, Fallat ME. Serum mullerian-inhibiting
substance levels during normal menstrual cycles. Fertil Steril.
2000;73:859–861.
25. Higgins RV, van Nagell JR Jr, Woods CH, Thompson EA,
Kryscio RJ.Interobserver variation inovarianmeasurementsusing
transvaginal sonography. Gynecol Oncol. 1990;39:69–71.
26. Syrop CH, Willhoite A, Van Voorhis BJ. Ovarian volume: a
novel outcome predictor for assisted reproduction. Fertil Steril.
1995;64:1167–1171.
27. Lass A, Skull J,McVeigh E, Margara R, Winston RM. Measurement
of ovarian volume by transvaginal sonography before ovulation
induction with human menopausal gonadotrophin for in-vitro
fertilization canpredictpoor response. Hum Reprod.1997;12:294–
297.
28. Sharara FI, McClamrock HD. The effect of aging on ovarian volume measurements in infertile women. Obstet Gynecol. 1999;94:
57–60.
29. Ruess ML, Kline J, Santos R, Levin B, Timor-Tritsch I. Age and the
ovarian follicle pool assessed with transvaginal ultrasonography.
Am J Obstet Gynecol. 1996;174:624–627.
30. Meldrum DR, Wisot A, Hamilton F, Gulary AL, Huynh D,
Kempton W. Timing of initiation and dose schedule of leuprolide influencesthe timecourse of ovarian suppression. Fertil Steril.
1988;50:400–402.
31. Scott RT, Navot D. Enhancement of ovarian responsiveness with
micro-doses of GnRH agonist during ovulation induction for in
vitro fertilization. Fertil Steril. 1994;61:880–885.
32. Scott RT, Hofmann GE, Muasher SJ, Acosta AA, Kreiner DK,
Rosenwaks Z. A prospective randomized comparison of single
and double lumen needles for transvaginal follicular aspiration.
J In Vitro Fert Embryo Transfer . 1989;6:98–101.
33. Kingsland CR,Taylor CT,AzizN, BiskertonN.Isfollicularflushing
necessary for oocyte retrieval? A randomized trial. Hum Reprod.
1991;6:382.
34. Tan SL, Waterstone J, Wren M, Parsons J. A prospective randomized study comparing aspiration only with aspiration and flushing
for transvaginal ultrasound directed oocyte recovery. Fertil Steril.
1992;58:356–360.
35. Hayes MF, Succo AG, Savoy-Moore RT, Magyar DM, Endler GC,
Moghissi KS. Effectofgeneralanesthesia on fertilization andcleavage of oocytes in vitro. Fertil Steril. 1987;48:975–981.
36. Soussis I, Boyd O, Paraschos T, Duffy S, Bower S, Troughton
P, Lowe J, Grounds R. Follicular fluid levels of midazolam, fentanyl and alfetanyl during transvagianl oocyte retrieval. FertilSteril
1995;64:1003–1007.
37. Coetsier T, Dhont M, DeSutter P, Merchiers E, Versichelen L,
Rosseel MT. Propofol anesthesia for ultrasound guided oocyte
retrieval: accumulation of the anesthetic agent in follicular fluid.
Hum Reprod 1992;7:1422.
38. Van Os HC, Roozenburg BJ, Janssen-Caspers HA, Leerentveld RA,
Scholtes MC, Zeilmaker GH, Alberda AT. Vaginal disinfectionwith
povidone iodine and the outcome of in-vitro fertilization. Hum
Reprod 1992;7:349–350.
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39. Biljan MM, Dean N,HemmingsR, Bissonnette F, Tan SL.Prospective randomized trial of the effect of two flushing media on oocyte
collection and fertilization rates after in vitro fertilization. Fertil
Steril. 1997;68:1132–1134.
40. Howe RS, Wheeler C, Mastroianni L Jr, Blasco L, Tureck R. Pelvic
infection aftertransvaginal ultrasound-guided ovumretrieval. Fer-
til Steril 1988;49:726–728.
41. Curtis P, Amso N, Keith E, Bernard A, Shaw RW. Evaluation of
the risk of pelvic infection following transvaginal oocyte recovery.
Hum Reprod 1992;7:625–626.
42. Ashkenazi J, Farhi J, Dicker D, Feldberg D, Shalev J, Ben-Rafael Z.
Acute pelvic inflammatory disease after oocyte retrieval: adverse
effects on the results of implantation.Fertil Steril 1994;61:526–528.
43. Yaron Y, Peyser MR, Samuel D, Amit A, Lessing JB. Infected
endometriotic cysts secondary to oocyte aspiration for in vitro
fertilization. Hum Reprod 1994;9:1759–1760.
44. Nargund G, Parsons J. Infected endometriotic cysts secondary
to oocyte aspiration for in vitro fertilization. Hum Reprod 1995;
10:1555.
45. Bennett SJ, Waterstone JJ, Cheng WC, Parsons J. Complication of
transvaginal ultrasound-directed follicle Aspiration. A review of
2670 consecutive procedure. J Assist Reprod Genet 1993;10:72.
46. Dicker D, Ashkenazi J, Feldberg D, Levy T, Dekel A, Ben-Rafael
Z. Severe abdominal complication after transvaginal ultrasonographically guided retrieval of oocytes for in vitro fertilization and
embryo transfer. Fertil Steril 1993;59:1313–1315.
47. Serour GI, Aboulghar M, Mansour R, Sattar MA, Amin Y, Aboulghar H. Complications of medically assisted conception in 3500
cycles. Fertil Steril 1998;70:638–642.
48. Hurley V, OsbornJ,LeoniM, Leeton J. Ultrasound-guided embryo
transfer: a controlled trial. Fertil Steril 1991;55: 559–562.
49. Soliman S, Daya S, Collins J, Hughes EG. The role of luteal phase
support in infertility treatment: a meta-analysis of randomized
trials. Fertil Steril. 1994;61:1068–1076.
Section 7.4. Ultrasonography and the Embryo Transfer
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Eric Flisser and Jamie A. Grifo
The original description of the “clinical touch” transfer technique
described advancing theembryo transfer cathetertipuntilcontact
was madewith the uterine fundus andsubsequently withdrawing
the catheter 5 to 10 mm before expelling the embryos. However,
as follow-up studies on transfer technique have demonstrated
the toxic consequences of provoking intrauterine bleeding and
the effect of induced uterine contractions, increased emphasis
has been placed on atraumatic technique. Because contact with
the uterinefundus isnow avoided, the definition of clinical touch
transfer has subsequently evolved to include transfers in which
contact with the uterine fundus isavoided, but additional machinations to identify catheter position, namely ultrasonography, is
not performed. This technique, sometimes described as “blind”
because visual confirmation of the location of catheter tip is not
made, relies on the operator’s subjective sense of catheter placement and other visual cues, such as depth markings placed at
regular intervals along the catheter, for successful execution.
Ultrasonography as an adjunct to embryo transfer was
employed early in the experience of human IVF, but this aspect
of assisted reproductive technology did not garner much interest
until vast improvements in other aspects of IVF, such as culture techniques, were made. The possibility that this seemingly
innocuous step could undermine the complex process that preceded it had been noted, but efforts to assess the utility of ultrasonography during embryo transfer were lacking. The first study
to illuminate the possibilities of ultrasonography and highlight
the pitfalls of blind embryo transfer techniques compared 12
transfers performed by clinical touch to 16 using transabdominal
ultrasonography.[1] When ultrasonography was performed, the
catheter was introduced into the uterine cavity until it was seen
curling as a result of contact with the fundus, and then it was
withdrawn slightly. In three of 16 transfers guided by ultrasonography (18.8%), the catheter was observed abutting the posterior
wall of the uterus after the operator had deemed the placement
satisfactory. The practitioner was unaware of the poorly positioned catheter until alerted by the ultrasound findings, which
suggested that clinical cues to catheter position might be insufficient. Ultrasound-assisted transfer was subjectively easier to perform, though this might have stemmed from operator bias, and
less bloodor catheter distortion was observed.The authors noted
that they did not have statistical proof that this was a superior
method of embryo transfer in the small number of subjects studied, but they recognized further investigation was needed.
The unreliable nature of traditional catheter placement was
also revealedinatransvaginalultrasonography studythatdemonstrated transfer catheters abutting the fundus in 17.4% and adjacent to a tubal ostium in 7.4% of 121 consecutive transfers.[2]
Whether complex manipulations required to place the transfer
catheter, remove the speculum, and introduce the vaginal probe
played a role in the final catheter location is a possibility, nevertheless, the practitioner was unaware of the catheter’s location
relative to anatomic landmarks.
ALTERNATE USE OF TRANSABDOMINAL
ULTRASONOGRAPHY (NOT ONLY FOR
EMBRYO TRANSFER)
The use of ultrasound has typically been to confirm the correct
placement of the transfer catheter tip, yet other applications are
available. One study assessed whether pretransfer measurement
of the uterocervical angle, an angle defined by a line aligning the
external and internal cervical os and another line extending from
the internal os through the fundus, would have an effect on transfer outcome.[3] This quasi-randomized study allocated patients
on an alternating basis to ultrasound-assisted or “clinical feel”
embryo transfer. Transfers done without ultrasonography were
done with straight catheters; those performed after ultrasound
assessment of the uterocervical angle had the transfer catheter
bent to mimic the degree of flexion. A Frydman TDT catheter
was used in all cases by first placing the rigid outer sheath with
its obturator, then replacing the obturator with the flexible inner
catheter for embryo transfer.
A marked improvement in pregnancy rate was demonstrated
when the angle was measured and the outer sheath molded
to mimic the degree of bend before transfer (26.3 vs. 18.4%,
P ≤ 0.02). The study observed a significant decrease in the pres-
ence of blood in the transfer catheter in the ultrasound group
(26.3% vs. 33.4%, P ≤ 0.05) as well as proportionally fewer difficult transfers (8.4% vs. 26.8%, P ≤ 0.00001). However, whether
this result arose from the use of ultrasonography or from bending the transfer catheter is unclear, and whether the difficulty of
transfer was a preexisting characteristic of these patients, because
allocation was not truly random, remains a possibility. Itis possible that placing a bend in the transfer catheter permits it to more
easily seek a path of least resistance, self-guiding its trajectory
through the cervical canal. Without a bend, the straight catheter
might resist conforming to the contour of the canal, abrading
the endocervix and initiating bleeding. Because the uterocervical angle was not measured in the control group, it is unclear
whether these patients had a higher proportion of steep uterocervical angles and if they would have benefited from a molded
catheter by comparison.
A significantly higher rate of volsellum forceps use was
observed in the control group (9.7% vs. 1.6%, P ≤ 0.00001),
which might have contributed to the study outcome, given the
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possibility of induced uterine contractions. The authors demonstrated that a wider uterocervical angle was associated with a
decreased chance of pregnancy. If ultrasound had been performed in both groups, measurement of the uterocervical angle
and the consequence of pretransfer catheter preparation could
have been more clearly assessed. The study authors, however, did
not compare an association with degree of difficulty and the uterocervical angle, though difficult transfers alone were not more
likely to lead to pregnancy failure. The presence of blood in the
catheterwasassociatedwithdecreasedpregnancyrates,asinother
studies (OR 0.54; 95% CI, 0.35–0.84). The study suggests that
placing a bend in the transfer catheter may facilitate its ease of
placement, particularly in cases in which a significant degree of
anteflexion or retroversion is suspected or has been previously
observed.
The Catheter
Many studies have attempted to determine the optimal embryo
transfer catheter.[4–8] Data have been conflicting, though transfer techniquesnow favor use of flexible catheters and minimizing
cervical manipulation. Atraumatic transferincludes avoidance of
contact with the uterine fundus that might provoke uterine contractions. The optimal catheter is one that can be reliably and
accurately placed with a minimum of tissue trauma.
Ultrasonography has been used as an adjunct in some of
these studies. A comparison of the Wallace and Frydman catheters
demonstrated no significant difference between catheters when
the choice of catheter was initially selected based on trial transfer
before the start of ovarian stimulation.[8] During the trial transfer, Wallace catheters were used and if successfully placed, slated
for use at the time of embryo transfer; if the catheter could not
be passed easily, the Frydman catheter was selected. At the time
of transfer, 6.5% of patients in the Wallace transfer group were
switched to theFrydman catheter becauseof difficulty at transfer.
The clinical pregnancy rates (41.6% vs. 36%) and implantation
rates (16% vs. 14.4%) were not significantly different between
groups, but showed a trend favoring transfer with the Wallace
catheter, which might be more clearly revealed in a larger study.
Blood, however, was seen on thecatheter morefrequentlywiththe
Frydman catheter (7.9% vs. 12.6%, P = 0.02). All transfers were
done underultrasound guidance. Because this study wasnot randomized and results not analyzed on an intention-to-treat basis,
it cannot directly compare whether these catheters yield equivalent results or whether prestimulation trial transfer can improve
ease of transfer, but suggests that Wallace catheters may be superior, and that additional manipulations to assist transfer with
this catheter, such as having the patient maintain a full bladder
or using a tenaculum to straighten the uterocervical angle, may
be warranted.
In a quasi-randomized study of transabdominal ultrasoundguided embryo transfer, the Wallace and Frydman transfer
catheters were compared; randomization for the use of ultrasound was done by availability of the ultrasonographer, and the
transfer catheter was chosenby the embryologist.[9] TheWallace
and the Frydman catheters yielded similar pregnancy rates
(30.3% and 30.7%, respectively).
As technicalimprovements such as the introduction of “soft”
embryo catheters have added to improved outcomes, changes in
design, such asimproved echogenicity of these catheters, may also
Figure 7.4.1. Sureview catheter visualized on transabdominal ultrasonography.
enhance their utility(Figure7.4.1). Whether these design changes
improve outcomes, or simply provide additional reassurance for
the operator, has yet to be conclusively demonstrated.
One observational study anecdotally reported subjective
improvement in visualization of a specially designed flexible
coaxial catheter, the Cook Echo-Tip catheter, in 20 embryo
transfers.[10] However, no comparisons were made during the
study, and whether improvedultrasound visualization would lead
to improvedtransfer outcomes was not investigated.The specially
designed catheter used an echogenic, stainless steel ring imbedded in the distal tip of the inner catheter. The authors postulated
that decreased manipulation of the inner catheter in attempts to
visualize the catheter during ultrasonography would cause less
disruption and trauma to the endometrium and might subsequently lead to improved outcomes. The sawing motion, they
reported, variously employed to identify traditional catheters,
might promote endometrial trauma. The authors also suggested
that this back-and-forth technique used to assist visualization of
the standard catheter might nullify gains achieved by employing ultrasound guidance, and might account for studies demonstrating equivalence in outcomes when ultrasound guidance is
tested against blind transfer techniques. However, although vigorous catheter movements might traumatize the endometrial lining, slight to-and-fro movements of the catheter may not be any
more damaging than complete withdrawal and replacement of
the catheter, as performed in the case of retained embryos.
A quasi-randomized comparison study of 251 patients comparing ultrasound assistance using either the Wallace catheter
or the Cook Echo-Tip catheter demonstrated no difference in
implantation rates (30% vs. 35%) and clinical pregnancy rates
(57% vs. 55%).[11] Although the authors reported improved
visualization of the specially designed catheter, it was not statistically more conspicuous than the standard catheter (100% vs.
95%), though it was subjectively easier to identify during transfers with obese patients or when the bladder was insufficiently
full. No improvement in outcomes was noted when analysis by
degree of technical difficulty was performed. Although no difference was seen, a power calculationwas not reported;additionally,
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