1413

inoculation of biopsy specimens (within 4 h after sampling), together with the use of a transport medium, to obtain improvement in isolation rates of H pylori. In our study, we found that such a procedure increased isolation rates from 21% (19/81) to 63%

(54/86). M. ASSOUS A. ZONE J. WATINE G. PAUL J. GUERRE

Departments of Bacteriology and Gastroenterology, Hôpital Cochin, 75014 Paris, France

1. Barthel JS, Everett ED. Diagnosis of Campylobacter pylori infections: the "gold standard" and the alternatives. Rev Infect Dis 1990; 12: S107-14. 2. Barbour AG. Isolation and cultivation of Lyme disease spirochetes. Yale J Biol Med

1984; 57: 521-25.

B has adopted A’s transfer technique and has since done 26 ETs, which have resulted in 12 pregnancies (46%), a significant improvement on results before his change of technique (p = 0-02). These surprising data suggest that small details in ET technique may result in large differences in pregnancy rate. We are planning a prospective study to examine systematically mechanical factors at embryo transfer. Department of Obstetrics and Gynaecology, King’s College School of Medicine and Dentistry, London SE5 8RX, UK

JOHN WATERSTONE RUTH CURSON JOHN PARSONS

JL, Turner SR, Murphy AJ. Embryo transfer technique as a cause of ectopic pregnancies in in vitro fertilization. Fertil Steril1985; 44: 318-21. 2. Menezo Y, Ducret L, Arnal F, Nicollet B, Humeau C. Increased viscosity in transfer medium does not improve the pregnancy rates after embryo replacement. Fertil 1. Yovich

Steril 1989; 52: 680-82.

Embryo transfer to low uterine cavity SIR,-Pregnancy rates after embryo transfer (ET) in in-vitro fertilisation programmes remain disappointing. Surprisingly few studies of ET technique have been reported. Practice has not changed over the past ten years. A syringe is attached to a fine plastic catheter into the tip of which is drawn 3-30 III of culture medium

containing the embryos; the loaded catheter is passed through the external cervical os and advanced a certain distance before pressure on the syringe plunger expels the embryos. Almost nothing is known about the location of the embryos immediately after transfer or by how much they move before implantation. Ectopic pregnancies after ET suggest that embryos can move large distances.’ Attempts have been made to immobilise them with hyperviscous transfer medium2 and fibrin sealant3 but neither modification significantly improved the pregnancy rate. Where should the embryos be deposited? Theoretically, it would seem advisable to place them close to the uterine fundus, to avoid deposition in the cervical canal or removal from the unterine cavity when the catheter is withdrawn. Almost all reports of ET technique describe placement of the catheter tip 5-10 mm from the uterine fundus. Our data suggest that deposition low in the uterine cavity results in a much better pregnancy rate. An atraumatic transfer catheter (Wallace) is preferred at this unit. Bladder filling and cervical traction are used, where necessary, to straighten the cervical canal. In about 15% of cases these measures fail to achieve passage of the soft catheter through the internal os and another transfer set incorporating a malleable metal introducer is used. We identified the clinician who did every 2-day ET between May, 1990, and January, 1991. Of the 296 transfers, 235 were done by two clinicians, A and B. There was a significant difference in pregnancy rate per transfer between A and B: —

No of transfers No pregnancies

Clinician A

Clinician B 137

98 45

(46 %)

33

(24 %) (p01)

Pregnancy outcome at 7 wk scan:

Preclinical

Anembryonic Ectopic 1 fetus 2 fetuses 3 fetuses

No of embryos per ET. 1 2 3 4 Patient age < 30 31-37 >38

6 2 1 22 13 1

3 4 1 17 7 1

9(9%) 65(66%) 24(25%)

14(10%) 76 (56%) 44 (32%) 3(2%)

0

3.

Feichtinger W, Barad D, Feinman M, Barg P. The use of two-component fibrin sealant for embryo transfer. Fertil Steril 1990; 54: 733-34.

Toxoplasma gondii antibodies in pregnant women

in Stockholm in 1969, 1979, and 1987

SIR,- Toxoplasma gondii infection is usually harmless but the fetus may be severely diseased if the mother is infected during pregnancy. In Sweden cases of congenital toxoplasmosis are very rare, according to national reporting to the National State Bacteriological Laboratory. Nevertheless, a congenitally infected baby may be without overt symptoms but still be at risk of late sequelae, such as chorioretinitis,1 which are not then linked with congenital toxoplasmosis. For this reason the rate of acquisition of toxoplasma during pregnancy is of some concern. In Sweden few epidemiological data are available. In a serological study in Stockholm in 1979 specific antibodies were found in 60% of women.2Data from southern Sweden indicate a seroprevalence of around 40% among pregnant women in 1982 and 1983.3 To elucidate the situation in the Stockholm area we have analysed consecutive sera from pregnant women for 1969, 1979, and 1987. l-in-20 samples of sera obtained for rubella immunity testing in antenatal clinics were studied. The socioeconomic structure was similar for the three years but the age distribution was not, there being a shift towards higher age between 1969 and 1979/87. A supplementary set of sera selected from routine virological diagnostic material at the Central Microbiological Laboratory, Stockholm, and collected in 1957-58, from women similar in age to those of the two later survey years were also studied. Data indicating country of origin were available for 1969,1979, and 1987. Sera from immigrants were excluded from the 1957-58 sample set on the basis of patients’ names. We used a direct agglutination test kit (Bio-Merieux). Formalinfixed toxoplasma (mainly membrane antigens) was mixed with serum. Sera causing agglutination at dilutions greater than or equal to 40 were considered indicative of previous exposure to T gondii infection. This assay accords well with other toxoplasma antibody tests.4 The prevalence of T gondii specific antibodies in pregnant women in Stockholm was 36-3% in 1969, 30-3% in 1979, and 21-1% in 1987. The figure for the 1957-58 sera was 47-7%. Seroprevalence fell with time in the Swedish and Finnish pregnant women, but not in other immigrants (table). The distribution, by age, of seroprevalence in non-immigrant pregnant women in Stockholm is shown in the figure. The proportion with specific anti-toxoplasma activity increases with age SEROPREVALENCE OFTOXOPLASMA ANTIBODY

(yr): 30(31%) 55(56%) 13 (13%)

37(27%) 86 (63%) 14(10%) The only factor that could explain this was a systematic difference in transfer technique: A introduced the catheter tip exactly 5 cm past the external os in all patients; B introduced the catheter further, advancing it very gently until resistance was felt and then

withdrawing it 5 mm before injection.

*Predominantly Yugoslavia, Greece,

and

Turkey

Embryo transfer to low uterine cavity.

1413 inoculation of biopsy specimens (within 4 h after sampling), together with the use of a transport medium, to obtain improvement in isolation rat...
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