Endometrial fluid visualized through ultrasonography during ovarian stimulation in IVF cycles impairs the outcome in tubal factor, but not PCOS, patients

BACKGROUND: The aim of the present study was to examine the impact of the presence of endometrial fluid (seen through ultrasound) on the outcome of IVF cycles and its association with the aetiology of infertility, in tubal and polycystic ovary syndrome (PCOS) cases specifically. METHODS: We retrospectively evaluated the charts of all PCOS and tubal factor infertility patients that underwent IVF between June 1, 2001 and May 31, 2002. Twenty-four PCOS and 14 tubal factor infertility patients in whom endometrial fluid was detected were compared with 94 PCOS and 160 tubal factor patients whose stimulation cycles did not show any fluid collection. The main outcome measures were implantation and pregnancy rates. RESULTS: Implantation rates were lower in the tubal factor patients in the presence of endometrial fluid (6.12% and 21.4%, respectively) in comparison with all other tubal factor infertile patients in whom no fluid accumulation inside the cavity was detected. In PCOS cycles there was no significance in patients with presence of endometrial fluid in comparison with the all other PCOS cycles without any fluid accumulation. CONCLUSIONS: When fluid collection inside the endometrial cavity is first seen during ovarian stimulation of PCOS patients undergoing IVF, embryo transfer can be performed safely if the fluid has disappeared and not returned by the day of embryo transfer. However, in tubal factor cycles one should think of either cancellation of the cycle or cryopreservation of all embryos.     

Recurrence of hydrosalpinges after transvaginal aspiration of tubal fluid in an IVF cycle with development of a serometra

The presence of hydrosalpinges has been shown to be deleterious in infertility treatment. Pregnancy rates after in-vitro fertilization (IVF) with embryo transfer decline considerably. This study concerns a patient who developed bilateral hydrosalpinges during controlled ovarian stimulation in preparation for IVF treatment. Transvaginal aspiration of the tubal fluid was unsuccessful as the tubes refilled within 2 days. Additionally, on the day of embryo transfer a serometra developed which could not be seen on the day of oocyte retrieval. The uterine cavity was evacuated via an embryo transfer catheter and three embryos were transferred. The serometra reappeared 3 days after embryo transfer. A pregnancy could not be achieved. The accumulation of fluid in the uterine cavity during an IVF/embryo transfer cycle is a rare complication of hydrosalpinges. However, the retrograde flow of tubal fluid may disturb intrauterine embryo development. This study suggests that the aspiration of hydrosalpinges and intrauterine fluid accumulation during an IVF cycle is not beneficial, as the underlying pathology is not cured. Cancellation of the treatment cycle or cryopreservation of oocytes in the pronucleate stage and transfer of the cryopreserved oocytes after surgical correction of the tubes may be better options.      

Hydrosalpinx affects the implantation of previously cryopreserved embryos

The presence of hydrosalpinx has been reported to negativelyaffect the pregnancy and implantation rate after in-vitro fertilization(IVF) with embryo transfer. Hydro-salpinges are able to enlargeduring ovarian stimulation with a possible increased passageof tubal fluid into the endometrial cavity. We report the effectof hydrosalpinges during the transfer of previously cryopreserved/thawedembryos during a natural cycle. In all, 14 transfers in 10 patientswith a sonographically-documented hydrosalpinx during the studiedcycle (group I) were compared to 98 cycles in 74 patients withtubal disease but no such sonographic finding (group II). Bothpregnancy and implantation rates were significantly lower ingroup I (7.14 versus 24.49% and 5.0 versus 10.8% respectively).The presence of hydrosalpinx negatively affects pregnancy andimplantation rates during natural cycles.     

Influence of position and length of uterus on implantation and clinical pregnancy rates in IVF and embryo transfer treatment cycles

In a prospective study of 807 consecutive women shown to have an apparently normal uterus after hysterosalpingography, hysteroscopy or pelvic ultrasonography prior to IVF or intracytoplasmic sperm injection (ICSI) and embryo transfer, the position and length of the uterine cavity was measured routinely at a pre-treatment mock transfer procedure. The apparent length of the uterine cavity was <7 cm in 128 women (group 1), 7-9 cm in 594 women (group 2) and >9 cm in 85 women (group 3). The uterus was noted to be retroverted in 38. 2% (308) women. The embryo transfer catheter was advanced to 5 mm from the uterine fundus based on the previously determined cavity length in all the embryo transfer procedures at 48 h after oocyte collection. Implantation and clinical pregnancy rates were not significantly different with respect to position of the uterus, difficulties encountered in passage of the catheter, mean age of the women, aetiology or duration of infertility or embryology events. An apparently greater cavity length was seen in older and/or parous women, but the difference was not statistically significant. Although the highest implantation and clinical pregnancy rates were seen in women with a cavity length of 7-9 cm (group 2) the differences were not statistically significant: group 1, 18.9 and 36. 7%; group 2, 21.0 and 46.5%; and group 3, 17.3 and 32.9% respectively. The incidence of ectopic pregnancy per reported clinical pregnancy was highest in group 1 women, being 14.9% (7/47) in comparison with group 2 (1.8%, 5/276) and group 3 (0%, 0/27) (P: < 0.0005), suggesting that the size of the uterus is a critical factor in the aetiology of ectopic pregnancy in IVF/ICSI-embryo transfer.     

Effect of endometriosis on IVF/ICSI outcome: stage III/IV endometriosis worsens cumulative pregnancy and live-born rates

BACKGROUND: Women with endometriosis often need IVF to conceive-most women need several cycles of treatment. METHODS: To evaluate the impact of moderate to severe endometriosis on cumulative IVF outcome, we carried out an observational study on 98 consecutive women who underwent IVF or ICSI treatment and had endometriosis diagnosed by laparoscopy or laparotomy and classified as minimal to mild endometriosis (American Society for Reproductive Medicine I/II) (n = 31) or moderate to severe endometriosis (American Society for Reproductive Medicine III/IV) (n = 67). The reference group consisted of 87 consecutive women with tubal infertility. The main outcome measures were cumulative pregnancy and live birth rates. RESULTS: There was a significantly lower pregnancy rate per fresh embryo transfer after pooled cycles (1-4) among women with stage III/IV endometriosis (22.6%) compared to stage I/II group (40.0%) or tubal infertility (36.6%). After 1-4 IVF/ICSI treatments, including frozen embryo transfer, 56.7% of the women with stage III/IV endometriosis were pregnant and 40.3% gave birth. The corresponding values were 67.7/55.8% when endometriosis was stage I/II and 81.6/43.7% in the controls respectively. CONCLUSION: Stage III/IV endometriosis means a worse prognosis for IVF/ICSI treatments compared to milder stages or tubal factors. Lower implantation and multiple pregnancy rates offer some support to our practice to continue two embryo transfers in this group.     

Effect of uterine leiomyomata on the results of in-vitro fertilization treatment

The effect of uterine leiomyoma on infertility is subject tocontroversy. Two main mechanisms associating leiomyomata andinfertility have been suggested: the obstruction of gamete transportand impaired implantation. In-vitro fertilization (IVF) is aunique setting for examining the effect of leiomyomata on theimplantation rate. This study was designed to determine theimpact of uterine leiomyomata on the results of IVF. In a retrospectiveanalysis of IVF cycles, 46 women with documented uterine leiomyomawere compared with a control group with mechanical infertility.The implantation rate and pregnancy outcome in relation to theleiomyoma were observed. Implantation (22.1%/transfer, 6.8%/embryo)and abortion rates (36%)in the study group were similar to theresults in the control group with pure mechanical factor. Ananalysis of IVF results according to the hysteroscopic pretreatmentfindings revealed that impaired implantation is associated withleiomyoma only where uterine intracavitary abnormalities co-exist.We conclude that implantation rate and pregnancy outcome areimpaired in women with uterine leiomyomata only when they causedeformation of the uterine cavity. In patients with leiomyomataassociated with an abnormal uterine cavity, surgical treatmentshould be considered prior to IVF because of the reduced implantationrate.     

Ultrasound-guided embryo transfer improves pregnancy rates and increases the frequency of easy transfers

BACKGROUND: Recent reports have suggested that ultrasound (US) guidance during embryo transfer might improve pregnancy rates. METHODS: A prospective randomized (computer-generated random table) trial was performed to compare embryo transfer under abdominal US guidance (n = 255 women) with clinical touch embryo transfer (n = 260). RESULTS: The clinical pregnancy rate was 26.3% (67/255) in the US-guided transfer group compared with 18.1% (47/260) in the clinical touch transfer group (P < 0.05). The implantation rate was 11.1% (100/903) in the US group compared with 7.5% (66/884) in the clinical touch group (P < 0.05). US-guided transfer was associated with a decrease in the difficulty of the transfers: 97% of transfers were easy in the US-guided group compared with 81% in the clinical touch group (P < 0.05). CONCLUSIONS: US-guided embryo transfer increased pregnancy and implantation rates in IVF cycles, as well as the frequency of easy transfers. It is suggested that the decrease in cervical and uterine trauma can play a role in the increase in pregnancy rates associated with US-guided transfer. It is recommended that embryo transfer should be performed under US guidance.     

Retrograde tubal embryo transfer in natural cycle in-vitro fertilization

Two modes of embryo transfer, uterine and tubal, were compared following natural cycle in-vitro fertilization (IVF). Only patients with patent Fallopian tubes were included in the study. Tubal embryo transfer was performed by retrograde tubal cannulation without analgesia on an outpatient basis. Tubal transfer conferred no benefit compared with uterine transfer in male factor infertility with positive fertilization (pregnancy rates of 15.8% in both groups). Although tubal embryo transfer in the patients with unexplained infertility improved the pregnancy rates from 7.8% in uterine transfer (5/64) to 17.6% in the tubal transfer group (13/74), this improvement was not statistically significant.      

A randomized controlled trial of a soft double lumen embryo transfer catheter versus a firm single lumen catheter: significant improvements in pregnancy rates

BACKGROUND: Embryo transfer has changed little since originally described in 1978. Clinicians rate the type of catheter used as the third most important variable in embryo transfer, but there are no adequately powered randomized trials. We compared the clinical pregnancy rates with the single lumen catheter (TCC) and the double lumen catheter (CC) in a randomized single blind trial. METHODS: A total of 650 cycles of women from the Adelaide University reproductive medicine units in Australia were included in this trial. Patients were <40 years of age undertaking IVF and embryo transfer. Exclusion criteria were: known uterine abnormality, day 3 FSH >10 IU/l, previous difficult embryo transfer and pre-implantation genetic diagnosis. Cycles were randomized from numbered sealed envelopes immediately prior to embryo transfer with stratification for fresh or frozen cycles. RESULTS: There was a significantly higher pregnancy rate in the group treated with the CC compared with the TCC catheter [29.6 versus 20.5% per embryo transfer, odds ratio (OR) = 1.63 (95% confidence interval: 1.14-2.30), P = 0.0076]. The point estimate for the OR was similar for fresh and frozen cycles. CONCLUSIONS: The pregnancy rate was increased by 50% and this justifies the increased cost of the soft double lumen catheter and the training of clinical staff required.     

Day 2 elective single embryo transfer in clinical practice: better outcome in ICSI cycles

BACKGROUND: Single embryo transfer (SET) after IVF/ICSI has been shown to result in an acceptable pregnancy rate in selected subjects. In our unit, SET is routinely carried out among women under the age of 36 in the first or second treatment cycle when a top-quality embryo is available. In order to define further the selection criteria for SET, we have analysed the outcome of elective SET (eSET), including the cumulative pregnancy rate after frozen embryo transfers, performed in the years 2000-2002 in the Oulu Fertility Center. METHODS: During the study period, a total of 1271 transfers were performed, and in 468 cycles SET (39% of all transfers) was carried out. Of the SET cycles, in 308 cases a top-quality embryo was transferred on day 2 and extra embryos were frozen. Of these eSET cycles, ICSI was carried out in 87 cycles (28%). RESULTS: The overall clinical pregnancy rate per transfer was 34.7% in the eSET cycles. In the eSET ICSI cycles, the clinical pregnancy rate was significantly higher than in the corresponding IVF cycles (50.6 versus 28.5%, P < 0.001). The cumulative pregnancy rate per patient after fresh and frozen embryo transfers was also significantly higher after ICSI (71.2 versus 53.4%, P < 0.01). CONCLUSIONS: A high cumulative pregnancy rate per oocyte retrieval can be achieved after eSET in daily clinical practice. The implantation rate of fresh top-quality embryos in the ICSI cycles was significantly higher than in the IVF cycles, possibly due to more successful selection of the embryo for embryo transfer on day 2 after ICSI. In addition, our data suggest that embryo quality is a more important determinant of outcome than the age of the woman.     

Comparative analysis of pregnancy rates after the transfer of early dividing embryos versus slower dividing embryos

BACKGROUND: We compared retrospectively the pregnancy outcome in two subgroups of ICSI patients, using early division (26 h post injection) to the 2-cell stage as a criterion for embryo quality and viability (ability to produce a pregnancy). METHODS AND RESULTS: In the early dividing embryo (EDE) group, at least one of the transferred embryos was early dividing. In the late dividing embryo (LDE) group, no early dividing embryo was transferred. Additionally, tubal and uterine transfer in the two groups was also evaluated. Clinical pregnancy rates in the EDE group were significantly increased when compared with that in the LDE group (41.3 versus 20.0%). This was also true for ongoing pregnancy rates (33.3 versus 16.3%). The tubal transfer route showed increased (but not significant) ongoing pregnancy rates when compared with uterine transfer in both EDE (38.5 versus 25.0%) and LDE (22.7 versus 8.3%) groups respectively. In uterine transfer cycles, however, clinical pregnancy rates for EDE were significantly increased compared to LDE (37.5 and 11.1% respectively). The baby rate (number of live babies/embryos transferred) was also significantly increased in the EDE group and the tubal transfer group. Statistical analysis of pregnancy outcome, adjusted for the total number of embryos transferred (expressed as percentage risk difference - %RD), resulted significantly in favour of EDE compared to LDE (RD = 18%, P = 0.02). When adjusted for the combined factors: total number of embryos transferred, EDE and LDE, the pregnancy outcome result was significantly in favour of tubal transfer compared to uterine transfer (RD = 15%, P = 0.05). Pregnancy results of the LDE group only were significantly better in the tube compared to the uterus (RD = 19%, P = 0.04) but not significantly so for the EDE group (RD = 10%, P = 0.4). CONCLUSION: Early division is associated with embryo quality and a very easy and successful embryo transfer selection method. Our results also suggest that when EDE are available, both tubal and uterine embryo transfer can be considered. When only LDE are available, however, tubal transfer should be the preferred transfer route.     

Microbiology of Human Follicular Fluid and the Vagina and Its Impact on in Vitro Fertilization Outcomes

PurposeThe present study aimed to identify microorganisms in follicular fluids and to investigate their association with in vitro fertilization (IVF) outcomes.Materials and MethodsThis study was conducted as a prospective study of 49 infertile females undergoing IVF/intracytoplasmic sperm injection cycles between 2013 and 2016. Paired follicular fluid and vaginal secretions were collected on the day of ovum pick up and were cultured to detect microorganisms.ResultsFifteen women (30.6%) had no microorganisms in follicular fluid or vaginal swabs, 23 (46.9%) had microorganisms on vaginal swab alone, 3 (6.1%) had microorganisms in follicular fluid alone, and 8 (16.3%) had microorganisms in both follicular fluid and vaginal swabs. The same microorganisms were detected in both the follicular fluid and vaginal swabs of three women, while different microorganisms were detected between follicular fluid and vaginal swabs in five women. Follicular fluid microorganisms were not associated with embryo quality or clinical pregnancy rates during IVF cycles. However, significantly decreased implantation rates (9.1% vs. 29.4%, p=0.031) and clinical pregnancy rates on embryo transfer day 5 (0% vs. 83.3%, p=0.048) were observed in the group that was positive for vaginal pathogens.ConclusionFollicular fluid contains microorganisms that can differ from those in the vagina of the same women; however, they do not appear to be associated with embryo quality or clinical pregnancy rates in IVF cycles. In contrast, vaginal pathogens were found to be associated with worse implantation rates and clinical pregnancy rates in IVF cycles.     

Ultrasound-guided embryo transfer: immediate withdrawal of the catheter versus a 30 second wait

It is essential to deposit embryos as gently as possible during IVF, avoiding manoeuvres that might trigger uterine contractions which could adversely affect the results of this treatment. The time during which the embryo transfer catheter remains in the cervical canal might be related to stimulation of contractions. This study investigates the influence that the time interval before withdrawal of the catheter after ultrasound (US)-guided embryo deposit might have on the pregnancy rate in patients under IVF cycles. A total of 100 women about to undergo transfer of at least two optimal embryos was studied. The women were prospectively randomized into two groups: (i) slow withdrawal of the catheter immediately after embryo deposit (n = 51); and (ii) a 30 s delay before catheter withdrawal (n = 49). The pregnancy rates for transfer in the two groups were 60.8 and 69.4% respectively, with no significant differences. There were no statistically significant differences in pregnancy rates between the two patient groups. The results indicate either that the waiting interval was insufficient to detect differences, or that the retention time before withdrawing the catheter is not a factor that influences pregnancy rate.     

Development of embryos from natural cycle in-vitro fertilization: impact of medium type and female infertility factors

Single embryos derived from natural cycle in-vitro fertilization(IVF) were graded during the pre-transfer culture period usingmorphological criteria. Most embryos developed well in culturewith 96% showing continuing division and 68% showing good morphologicalappearance, although embryo quality tended to decline with anincreased incidence of fragmentation and uneven cleavage asdivision proceeded. Both the pregnancy rate and the distributionof embryo grades were similar among four different culture mediaused, suggesting that choice of medium had little impact onoutcome. In contrast, there were marked differences in pregnancyrate according to the type of infertility, which was not reflectedin a decrease in embryo quality. However, although embryos frompatients with tubal infertility implanted and formed viablepregnancies irrespective of morphological appearance, only ‘good’quality embryos from patients with non-tubal (or ‘unexplained’)infertility were able to implant. Thus the appearance of theembryo derived from natural cycle IVF in women with unexplainedinfertility may be of clinical relevance.     

Comparison of pulsatility indices on the day of oocyte retrieval and embryo transfer

Transvaginal ultrasonography with colour blood flow imagingand analysis of impedance to uterine arterial blood flow hasbeen used to provide an index of uterine receptivity for implantationafter IVF/embryo transfer. A mean uterine arterial pulsatilityindex (PI) >3.0 at the time of embryo transfer predicted35% of failures to become pregnant. Cryopreserving embryos innon-receptive cycles and transferring them in receptive cycleswould be expected to improve pregnancy rates. Earlier decisionsregarding embryo cryopreservation can be made if receptive cyclescan be predicted at the time of oocyte retrieval rather thanat embryo transfer. To assess differences in uterine arteryimpedance, PI were measured serially in 107 women on both theday of oocyte retrieval and the day of embryo transfer. MeanPI on the day of oocyte retrieval was 2.52 ± 0.59, andon the day of embryo transfer was 2.78 ± 0.45. No significantdifference was observed when PI determined on the day of oocyteretrieval were compared with PI on the day of embryo transfer.These data suggest that the PI measurement done on the day ofoocyte retrieval could substitute for the measurement done onthe day of embryo transfer. This would allow prediction of non-receptiveendometria earlier in the cycle. Further studies are neededto evaluate whether cryopreservation of embryos and transferwhen the uterus is more receptive will increase the implantationrates.     

The effect of intercourse on pregnancy rates during assisted human reproduction

Intercourse during an IVF cycle has the potential to improve pregnancy rates since exposure to semen is reported to promote embryo development and implantation in animals. Conversely, coitus-induced uterine contractions or introduction of infection may have a detrimental effect. A multicentre prospective randomized control trial was conducted to determine if intercourse during the peri-transfer period of an IVF cycle has any influence on pregnancy success. Participants undergoing thawed embryo transfer (Australian centre) or fresh embryo transfers (Spanish centres) were randomized either to abstain or to engage in vaginal intercourse around the time of embryo transfer. The transfer of 1343 embryos during 478 cycles of IVF resulted in 107 pregnancies (22.4%), with 125 viable embryos remaining by 6-8 weeks gestation. There was no significant difference between the intercourse and abstain groups in relation to the pregnancy rate (23.6 and 21.2% respectively), but the proportion of transferred embryos that were viable at 6-8 weeks was significantly higher in women exposed to semen compared to those who abstained (11.01 versus 7.69 viable embryos per 100 transferred embryos, P = 0.036, odds ratio 1.48, 95% confidence interval 1.01-2.19). Hence exposure to semen around the time of embryo transfer increases the likelihood of successful early embryo implantation and development.     

Heterotopic triplet pregnancy: report of a case with bilateral tubal pregnancy and an intrauterine pregnancy

The first report of an ectopic pregnancy following IVF was published in 1976, and since then heterotopic pregnancies (HPs) have been reported at an increasing rate. Although cases of the co-existence of a bilateral tubal and an intrauterine pregnancy following IVF-embryo transfer have been reported, a case of heterotopic triplet pregnancy caused by unilateral tubal embryo transfer has not yet been published in the literature. Here we report on a 38-year-old women (gravida 3, para 1) with a history of infertility who presented to our infertility clinic for evaluation. Hysterosalpingography revealed bilaterally patent Fallopian tubes and stricture of the cervical canal. She conceived after receiving HMG combined with pure FSH, followed by IVF-tubal embryo transfer. Four embryos were replaced into the right tube. Approximately 5 weeks after tubal embryo transfer, the patient presented with lower abdominal tenderness and shock due to internal bleeding. She underwent an emergency laparotomy under the impression of HP. Bilateral tubal pregnancy with right tubal rupture was noted during the operation. The post-operative course was uneventful. Early intervention and thorough inspection of the peritoneal cavity in patients with haemodynamic instability can prevent jeopardizing the life of the mother as well as the ongoing pregnancy.     

Single top quality embryo transfer as a model for prediction of early pregnancy outcome

BACKGROUND: Single embryo transfer (particularly of a top quality embryo) is an excellent model to correlate embryo quality in terms of morphological criteria to early pregnancy. We investigated whether this model could provide us with more information on what happens after implantation in the first trimester of pregnancy. METHODS: The outcome of 370 consecutive single top quality embryo transfers in patients younger than 38 years was analysed for pregnancy and first-trimester pregnancy loss (FTPL) before 13 weeks of gestation. Analysis was done on each cohort of embryos from which the transferred top quality embryo was selected. Serum HCG levels were measured on day 8 and day 12 after day 3 embryo transfer. The HCG index was calculated as the level of HCG on day 12/HCG on day 8. RESULTS: The pregnancy rate after single top quality embryo transfer was 51.9%. This was independent of the patients' age. FTPL, however, appeared to be age dependent: 15.4% for the whole group, 9% in patients younger than 30 years and 19% in patients above 30 years. The pregnancy rate was 50% in IVF cycles and 52% in ICSI cycles; FTPL was 19% in IVF cycles and 10% in ICSI cycles. Multiple regression analysis showed that these differences originated from age differences between both populations rather than from technique-related factors. An HCG level >or=45 IU/l on day 12 was predictive for ongoing pregnancy with 75.6% sensitivity and 100% specificity; an HCG index >or=3.5 similarly predicted ongoing pregnancy with 72.3% sensitivity and 100% specificity. CONCLUSIONS: These data show that embryo selection for transfer on day 3 can be used as an excellent tool for prediction of pregnancy but not for prediction of FTPL. The pregnancy rate of a single top quality embryo is not related to age, whereas FTPL is age dependent.     

Infertility: In-vitro fertilization in completely natural cycles

Our objective was to assess the efficacy of in-vitro fertilization(IVF) in natural ovarian cycles in couples with tubal and unexplainedinfertility. A prospective study design was used. A total of39 fully investigated couples, who were patients at the ReproductiveMedicine Unit, St Michael's Hospital, Bristol, UK, took part;they were diagnosed with either tubal disease (n = 26) or unexplainedinfertility (n = 13). Procedures involved daily capillary bloodsampling, daily vaginal ultrasonography and vaginal oocyte recoveryunder sedation at mid-cycle. The main outcome measures werefertilization, implantation and pregnancy rates. Although moreof the women with tubal disease were parous, there were no othersignificant differences between the two groups. The 39 coupleswith infertility of tubal or unexplained aetiology had 79 cyclesof IVF in otherwise completely natural cycles. The overall fertilizationrate was 80% and the implantation rate was 14.0%. A trend wasobserved for higher success rates in women with tubal disease.We conclude that natural cycle IVF and embryo transfer offersan acceptable chance of pregnancy and an opportunity for thein-depth investigation of follicular and ovarian function incouples with defined causes of infertility. The possibly lowersuccess rate in women with unexplained infertility warrantsfurther study of follicular function and endocrinology.     

Pregnancy: A challenge to the concept of tubal reflux to explain the rise and fall of CA125 in serum during the first trimester

Although amniotic fluid concentrations of cancer antigen (CA)125 rise during the first two trimesters of pregnancy, the serumconcentrations of CA125 peak during the first trimester anddrop to non-pregnant values in the second and third trimester.A previous hypothesis to explain this phenomenon was that inthe early first trimester decidual CA125 gains access to thematernal compartment via ‘tubal reflux’ and subsequentabsorption by peritoneal lymphatics. However, as pregnancy advances,the decidua capsularis fuses with the decidua parietalis, thusobliterating the endometrial cavity at 10–12 weeks; theFallopian tubes thus become functionally obstructed. To testthis hypothesis, we evaluated early first trimester CA125 concentrationsin women conceiving by in-vitro fertilization (IVF) and embryotransfer with patent tubes (group 1) and in those conceivingby IVF and embryo transfer with bilateral tubal occlusion (group2). We also compared those conceiving with human menopausalgonadotrophin therapy for ovulation induction without assistedreproduction (group 3) and those conceiving without fertilitydrugs in assisted reproduction (group 4). Mean CA125 concentrationswere similar in groups 1–3; the mean CA125 concentrationin group 4 was lower but this difference was not statisticallysignificant, probably due to the small sample size. These datado not support the concept that tubal reflux explains the riseand fall of serum concentrations of CA125, since these wereequal in IVF conceptions with or without tubal patency.