Junctional zone contractions and embryo transfer: is it safe to use a tenaculum?

P. Lesny1,3,4, S.R. Killick1,3, J. Robinson2,3, G. Raven3 and S.D. Maguiness1,3

1 Academic Department of Obstetrics and Gynaecology and 2 Department of Biological Sciences, University of Hull, Cottingham Road and 3 The Hull IVF Unit, Princess Royal Hospital, Saltshouse Road, Hull, UK


    Abstract
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 Abstract
 Introduction
 Materials and methods
 Results
 Discussion
 References
 
Applying a tenaculum to the cervix is a common practice when the correction of uterine position prior to embryo transfer is required. Our study was designed to assess junctional zone contractility before and after this procedure in 20 patients at the time of mock embryo transfer (mid-luteal phase, at commencement of down-regulation). Real-time transvaginal ultrasound and computer technology was used to evaluate the contraction pattern and frequency. When a tenaculum was applied, the total number of contractions, the number of cervico–fundal, random and opposing contractions all increased significantly (P values 0.0003, 0.005, 0.001 and 0.007 respectively). Eleven women displayed cervico–fundal contractions, prominent opposing and random contractions were observed in all 20 patients and four patients generated fundo–cervical waves not seen in any case before stimulation with the instrument. In conclusion, manipulation with a tenaculum in the cervical area stimulates junctional zone contractions and is best avoided at the time of embryo transfer.

Key words: embryo transfer/junctional zone contractions/tenaculum/transvaginal ultrasound


    Introduction
 Top
 Abstract
 Introduction
 Materials and methods
 Results
 Discussion
 References
 
Uterine junctional zone (JZ) contractions or endometrial wavelike movements have been described in both natural (Ijland et al., 1996Go, 1997bGo; Kunz and Leyendecker, 1996Go) and assisted reproduction cycles (Lesny et al., 1998bGo). A study of fertility during a natural cycle has revealed that lower endometrial mobility throughout the entire cycle and different contraction characteristics are associated with a higher pregnancy rate (Ijland et al., 1997aGo). It has been shown recently (Fanchin et al., 1998aGo) that increased JZ contractility in patients just before embryo transfer is associated with a lower pregnancy rate. We have also reported (Lesny et al., 1998aGo) stimulation of JZ contractions and relocation of mock embryos towards the cervix and into the Fallopian tubes after performing difficult mock embryo transfers in oocyte donors.

Embryo transfer is one of the most critical steps affecting the success rate of in-vitro fertilization (IVF) and has changed little since IVF was first described. While there is general agreement that a smooth embryo transfer is associated more frequently with successful outcome (Wood et al., 1985Go; Mansour et al., 1990Go; Visser et al., 1993Go; Tomas et al., 1998Go), this opinion is not unanimous (Nabi et al., 1997Go; Tur-Kaspa et al., 1998Go). There is also no consensus about how an embryo transfer can be classified as an easy or difficult procedure. The importance of several variables associated with embryo transfer has been recently recognized (Kovacs, 1999Go). A correction of uterine position, by applying traction to the cervix with a tenaculum, is a procedure sometimes used prior to embryo transfer. The aim of this study was to evaluate whether this has any effect on JZ contractions.


    Materials and methods
 Top
 Abstract
 Introduction
 Materials and methods
 Results
 Discussion
 References
 
Patients
This research project was approved by Hull and East Riding Research Ethics Committee. All patients were counselled and took part on a voluntary basis. We asked 20 patients undergoing IVF or intracytoplasmic sperm injection (ICSI) to participate in this study. Women with ovulatory disorders, endometriosis, hydrosalpinges and abnormal uteri were not included. No patient was on any additional medication or had a history of operation on the uterus (including minor procedures involving the uterine cervix).

Procedure
Our investigations were performed before mock embryo transfer, which we do routinely in all patients at the time of down-regulation (mid-luteal phase). The patients were assessed by transvaginal ultrasound scan (ATL, Ultramark 4; 5 MHz endovaginal transducer, Advanced Technology Laboratories, Seattle, WA, USA) for 2 min to obtain baseline JZ activity. At each examination a scan image of the mid-sagittal plane of the uterus was videotaped. This was followed by application of Littlewood's tissue forceps to the upper lip of the cervix. After one movement mimicking correction of the uterine position, the instrument was released. Recording was continued for a further 2 min. The images were later digitized into a computer and converted to five times normal speed to allow analysis of JZ contractions as we have previously described in detail (Lesny et al., 1998aGo,bGo).

We used the wave classification system introduced by Ijland et al. (1996), which includes five types of endometrial movements: no activity; waves from cervix to fundus; waves from fundus to cervix; opposing waves starting simultaneously at cervix and fundus; and random waves originating at various foci (Ijland et al., 1996Go). Contraction pattern and frequency were rated by two independent observers. These observations were evaluated on SPSS for Windows (SPSS UK Ltd, St Andrew's House, Woking, Surrey, UK) using Wilcoxon matched-pairs signed-ranks test.


    Results
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 Abstract
 Introduction
 Materials and methods
 Results
 Discussion
 References
 
All 20 patients before application of the tenaculum displayed only minimal JZ contractility, predominantly in the form of random and opposing endometrial movements (Table IGo). When the instrument was used the total number of contractions, the number of cervico–fundal, opposing and random contractions increased significantly (Table IIGo). Eleven women displayed strong cervico–fundal contractions. Eight of them had contractions generated de novo with a frequency of 3.8 ± 1.3 waves/min and in three cases cervico–fundal contractions were of a higher frequency than before stimulation (2.6 waves/min and 4.3 waves/min respectively). Four women developed fundo–cervical contractions of frequency 3.4 waves/min. Prominent opposing waves and strong random waves were observed in all 20 patients. Random waves seemed to have higher amplitude and involved a greater length of endometrium.


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Table I. Characteristics of junctional zone (JZ) contractions in individual patients before and after the application of a tenaculum to the cervix
 

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Table II. Total number of junctional zone contractions in a group of 20 patients before and after the application of a tenaculum to the cervix
 

    Discussion
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 Abstract
 Introduction
 Materials and methods
 Results
 Discussion
 References
 
The characteristic of the JZ prior to application of the instrument to the cervix was similar to activity observed during the normal luteal phase (Ijland et al., 1996Go, 1997bGo). We did not notice any fundo–cervical contractions before stimulation, thus the appearance of strong contraction waves of this type after stimulation in four patients was quite striking. Although the number of patients who developed fundo–cervical contractions was low, and the difference in the frequency of this type of contraction before and after application of the tenaculum was not statistically significant, there appeared to be an increasing trend after stimulation, as was more apparent with other patterns.

The ability of fundo–cervical contractions to move the mock embryo towards the cervix has previously been demonstrated (Lesny et al., 1998aGo) after stimulation of the uterine fundus with the embryo transfer catheter. Real embryos have also been found in the vagina following embryo transfer (Poindexter et al., 1986Go; Schulman, 1986Go). Experimental studies of mock embryo transfer in humans showed expulsion of methylene blue in 57% of transfers (Mansour et al., 1994Go) and movement of X-ray contrast medium towards the cervix and vagina in 21% (Knutzen et al., 1992Go). Interestingly, some of the original research on animals in the early 1960s (Harper et al., 1961Go; Rowson et al., 1964Go) also showed that transcervical embryo transfer was associated with expulsion of resin spheres impregnated with radioactive gold (artificial ova), whilst surgical transfer (bypassing the cervix) offered better and more consistent results (Betteridge and Rieger, 1993Go). Our observation suggests that the application of Littlewood's tissue forceps may potentiate an adverse uterine response already associated with the mechanism of transcervical embryo transfer.

Theoretically, the JZ contractions in the cervico–fundal direction which we saw in 11 patients (in eight cases stimulated de novo and in three patients with higher frequency than before stimulation) should have a positive effect and keep the embryos inside the uterine cavity. On the contrary, as opposing and random contractions represent the dominant pattern during the luteal phase in both natural (Ijland et al., 1996Go) and assisted reproduction cycles (Lesny et al., 1998bGo), cervico–fundal contractions may push the embryo into the Fallopian tube or prevent an embryo's descent if it is already there.

We consider the significantly increased number of the opposing waves and strong random waves after application of the tenaculum to be equally dangerous as waves of regular pattern. We have previously reported that strong random waves within the uterine fundus generated by stimulation with the transfer catheter in this area (Lesny et al., 1998aGo) were able to push a mock embryo through the utero–tubal junction. We observed, however, that while movements of mock embryos usually occur within 5 min following transfer, the increased uterine contractility was present even 45 min later. These observations provide an explanation for earlier clinical studies (Yovich et al., 1985Go; Nazari et al., 1993Go). They demonstrated that their embryo transfer technique in which embryos were not placed near the uterine fundus was associated with a lower ectopic pregnancy rate without compromising the intrauterine pregnancy rate. Interestingly, during our study, we observed that the uterus responded with contractions of opposing or strong random patterns in the fundal area when we stimulated not the uterine fundus but the uterine cervix.

It is known that JZ contractions change during both natural (Ijland et al., 1996Go, 1997aGo,Ijland et al., bGo; Kunz and Leyendecker, 1996Go) and stimulated cycles (Abramowicz and Archer, 1990Go; Fukuda and Fukuda, 1994Go; Lesny et al., 1998bGo). It has been observed (Fanchin et al., 1998bGo, 1999Go) that at the time of embryo transfer, higher concentrations of serum progesterone were associated with contractions of lower frequency, and increased endometrial echogenicity. Indirect support for the role of progesterone as a possible regulator of JZ contractility has been provided (Mahmood et al., 1998Go). They reported changes in epithelial ciliary beat frequency of the Fallopian tube, which was significantly suppressed in vitro by progesterone. This may be in agreement with the new concept of an endometrial–subendometrial unit or `archimetra', which according to one proposed theory (Leyendecker et al., 1998Go; Noe et al., 1999Go) is of paramesonephric origin; thus, the contractility of Fallopian tubes and JZ contractions may have similar, hormonally dependent, regulation.

Several substances were found to alter contractility of isolated myometrial strips in vitro (Morizaki et al., 1989Go; Martinez-Mir et al., 1990Go, 1992Go; Rudolph et al., 1993Go) but efforts to improve uterine receptivity by trying to relax the uterus with prostaglandin synthetase inhibitors (Poindexter et al., 1986Go; Schulman, 1986Go), ritodrine (de Kretzer et al., 1983Go), diazepam (Meldrum et al., 1987Go) and glyceryl trinitrate (Shaker et al., 1993Go) or by transferring embryos under general anaesthesia (Diedrich et al., 1989Go), have all failed. It has recently been reported (Mori et al., 1997Go) that the human uterus is characterized by a large number of mast cells. These mast cells are especially numerous in the inner part of the myometrium and are closely associated with bundles of smooth muscle cells (Mori et al., 1997Go). We can only postulate that stimulation of JZ contractions during embryo transfer is caused by mast cells releasing the inflammatory reaction mediators such as histamine, serotonin and prostaglandins after application of a tenaculum to the cervix or stimulation of the endometrium and inner myometrium by an embryo transfer catheter. Thus, this local reaction and the proximity of the responding cells (densely packed myocytes of the JZ layer) may make attempts at pharmacological treatment difficult.

In summary, manipulation with a tenaculum in the cervical area stimulates JZ contractions and is best avoided at the time of embryo transfer. As the precise endocrine mechanism for these contractions is yet to be determined, pharmacological control to reduce this contractility remains elusive.


    Acknowledgments
 
Dr Eric Gardiner, Department of Mathematics, University of Hull is kindly thanked for his suggestion regarding the statistical analysis. We are grateful to all our IVF team for their assistance and to all of the patients who made this project possible. The Hull IVF Trust is gratefully acknowledged for financial support.


    Notes
 
4 To whom correspondence should be addressed at: The Hull IVF Unit, Princess Royal Hospital, Saltshouse Road, Hull HU8 9HE, UK Back


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 Abstract
 Introduction
 Materials and methods
 Results
 Discussion
 References
 
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Submitted on March 8, 1999; accepted on May 20, 1999.