Doi:10.1016/j.fertnstert.2003.09.062

FERTILITY AND STERILITY௡
Copyright 2004 American Society for Reproductive Medicine Printed on acid-free paper in U.S.A.
Analysis of factors influencing pregnancy
rates in homologous intrauterine
insemination
Gilberto Ibe´rico, M.D.,a Jesu´s Vioque, M.D., Ph.D.,b Nuria Ariza, M.D.,aJose Manuel Lozano, M.D.,a Manuela Roca, M.D.,a Joaquı´n Lla´cer, M.D.,a andRafael Bernabeu, M.D.a Instituto Bernabeu, Alicante, Spain Objective: To identify predictors of pregnancy rate (PR) among women undergoing homologous IUI.
Design: Cross-sectional analysis of IUI cycles carried out from January 2000 to September 2002.
Setting: Private infertility center in Alicante, Spain.
Patient(s): Four hundred seventy women undergoing 1,010 cycles of IUI.
Intervention(s): Single IUI with ovarian stimulation using hMG.
Main Outcome Measure(s): Preovulatory follicles (Ͼ15 mm), motile spermatozoa count, type and duration
of infertility, female age, insemination timing, and cycle number.
Result(s): Overall PR per cycle and multiple pregnancy and miscarriage rates were 9.2%, 8.6%, and 11.8%,
respectively. Three significant predictors of pregnancy were identified by multiple logistic regression analysis:
preovulatory follicles, spermatozoa count, and infertility duration. Interuterine insemination with three
follicles almost tripled the PR with respect to only one, odds ratio (OR) ϭ 2.89 (95% confidence interval [CI],
1.54 –5.41). Compared with insemination with a motile sperm count Ͼ30 ϫ, 20.1–30, 10.1–20, 5.1–10, and
Յ5 ϫ106, insemination progressively decreased the PR, from 15.3% in the highest category to 3.6% in thelowest (OR lowest/highest ϭ 0.20 [95% CI: 0.09 – 0.45]), with a statistically significant dose-response trend.
Infertility duration Ն3 years was marginally associated with a lower PR, OR ϭ 0.65 (95% CI, 0.40 –1.04).
Overall, female age was not a significant predictor of pregnancy, and although PR slightly decreased beyondtwo IUI cycles and when a single IUI was performed 36 – 40 hours after hCG administration, results were notstatistically significant.
Conclusion(s): Homologous IUI achieves the best results with two or three induced follicles, a high motile
spermatozoa count, and infertility duration Ͻ3 years, irrespective of female age and fertility history. (Fertil
Steril௡ 2004;81:1308Ϫ13. 2004 by American Society for Reproductive Medicine.)
Key Words: Homologous intrauterine insemination, human menopausal gonadotropin, pregnancy rate,
prognostic factors, motile spermatozoa count 2003; revised andaccepted September 17,2003.
cause it increases the number of available oo- Homologous IUI using different methods of cytes for fertilization and the number of sper- semen preparation is a less expensive and in- vasive treatment than other assisted reproduc- tive techniques. It is usually selected as a first In a recent review of the efficacy of treatment option treatment for infertile couples with for unexplained infertility, hyperstimulation with rbernabeu@institutobernabeu.
com).
patent tubes, cervical factor, mild endometrio- clomiphene citrate (CC) was shown to be a cost- sis, or mild or moderate male factor or as effective treatment, although the use of gonado- empirical treatment in unexplained infertility tropin seemed to be a more efficacious option in Publica, UniversidadMiguel Herna´ndez, San (COH) using gonadotropins with IUI has been evidence for a superior effect according to the shown to be a most effective treatment of in- type of gonadotropin used in IUI treatment, we fertility compared with timed vaginal inter- routinely started with hMG because it was the least expensive medication and significantly doi:10.1016/j.fertnstert.2003.
09.062 with IUI in natural cycles presumably be- The important differences observed in predictors of preg- sample quality. The isolated fraction of motile sperm was nancy rates (PRs), which usually range between 8% and 26% diluted in 0.5–1 mL of the same preparation medium and may be mainly due to the influence of different factors incubated at 37°C for 40 – 45 minutes until IUI.
on cycle outcome In this sense, some factors such assperm count and follicle development have been Ovarian Stimulation and Timing of
positively related to PRs, whereas others like a high cycle Insemination
number and higher female age have been negatively associ- HMG (hMG-Lepori; Farma-Lepori, Barcelona, Spain) ated Although results may appear concordant for combined with hCG (Profasi HP 2500, Serono, Madrid, some of these factors, a lack of consistency is still evident for Spain) were used to induce ovulation. Administration of some of them, such as female age addition of COH hMG was usually started on day 3 of the patient’s cycle. The routine commencement dose was 150 IU for 3 days in astep-down process. However, patients with polycystic ovary To improve subfertility treatment and achieve the best PR disease or young women with a high risk of multiple preg- in individual couples, we attempt to identify which factors nancy used a low-dose regimen starting with 75 IU for five may contribute to the success of COH/hMG/IUI cycles with consecutive days until the first transvaginal ultrasound test.
In addition, in older patients and/or those with a probable orproven decrease of ovary reserve, the initial COH dosebegan with 225 IU hMG. Although the hMG dose was MATERIALS AND METHODS
decreased according to the circumstances, in a few cases itwas increased in response to a low follicle development or Subjects
This study was based on data collected from the records Follicular development was monitored by transvaginal of 470 consecutive infertile couples who were referred for ultrasound on alternate days, starting on days 6 – 8 of the 1,010 male partner IUI cycles to our center in the period cycle, and eventually a blood E level according to physician 2000 –2002. Institutional Review Board approval was not criteria. If more than five follicles Ͼ15 mm diameter in both required for this observational study because patients were ovaries or an E level Ͼ1,500 pg/mL were documented, the treated according to standard and customary clinical prac- treatment was cancelled to avoid the high-risk multiple preg- tice. Couples were studied by means of several tests that nancy. As an alternative, couples were asked to consider included a postcoital test, midcycle P level, tubal patency timed intercourse or an IVF procedure.
assessment either by hysterosalpingogram or by laparos-copy, and two seminograms, with at least one of them Patients were asked to abstain from intercourse when the follicle diameter exceeded 15 mm. When the leading folliclereached 18 –20 mm and, preferably, when two to four folli- Criteria for subjects’ inclusion were [1] Ն1 year of pri- cles with a diameter Ͼ15 mm were observed, 5,000 IU of mary or secondary infertility; [2]) female partner Ͻ45 years hCG were given and a single IUI was randomly performed of age at the time of treatment with a normal ovulation 24 –28 or 36 – 40 hours after hCG administration. Four or history or ovulate response to medication; [3] female partner more cycles per couple were rare (8.5%). Treatment reeval- with bilateral patent fallopian tubes demonstrated within past uation was performed when one patient failed to conceive 2 years; and [4] male partner with at least two semen after 3– 4 cycles. Cancelled cycles, mainly due to ovarian analyses to confirm diagnosis and at least one trial sperm hyperstimulation or absence of ovarian response, were not washing with a quantity of Ն5 ϫ 106 of motile spermatozoa.
included in the analysis since they did not progress to IUI. In In spite of this last general requirement, which is aimed at addition, 10 cycles were excluded from final analysis be- obtaining the highest success rate in IUI cycles, those pa- tients with a lower sperm count after preparation on the dayof IUI performance were finally included.
Insemination Procedure and Detection of
Pregnancy
Sperm Preparation
The cervix was exposed with a bivalve speculum and Couples were requested not to have intercourse for 3–5 cervical mucus cleaned with a cotton dressing. Hard (Gy- days before the day of semen collection. Semen samples netic, Gynetics Medical products; Hamont-Achel, Belgium) were produced by masturbation and collected in sterile con- or soft (Embryon, Embryo Transfer Set; Rocketmedical tainers. After complete liquefaction for 30 minutes at room PLC, Whashington, England) catheters were allocated with- temperature, each sample was analyzed using World Health out distinction to slowly inject 0.5–1 mL of prepared semen Organization/Kruger guidelines. Semen for IUI was pre- with motile spermatozoa into the uterine cavity, approxi- pared by selecting the motile sperm fraction for all samples, mately 0.5 cm below the fundus. Qualitative hCG urine tests performing one or more swim-up trials with Sperm Prepa- were performed 15 days after insemination to determine the ration Medium (Medi-Cult, Jyllinge, Denmark) to improve establishment of the biochemical pregnancy. Clinical preg- FERTILITY & STERILITY௡
nancy was defined as one with presence of an embryonic sacconfirmed by ultrasound scanning. Luteal support was not given because we determined that there was no physiological Pregnancy rates in patients undergoing homologous intrauterine insemination (IUI) according to different Data Collection and Statistical Analysis
Data from all consecutive patients who were referred for IUI cycles at the Infertility Center between 2000 and 2002 were included in this study. During this period, 1,010 IUI cycles were performed on 470 women. Information concern- ing pregnancy, multiple pregnancy, or abortion was recorded The variables selected for the analysis were female age, number of preovulatory follicles, sperm count, type, and duration of infertility, cycle number, dominant follicle diam- eter, ovulatory ovarian side, insemination timing, and cath- eter type and Female age and follicle number were categorized as follows: Ͻ30, 30 –34, 35–39, or Ն40 years, and 1, 2, 3, or Ն4 follicles, respectively. Categories for total motile sperm count inseminated were Ͻ5 ϫ, 5.1–10 ϫ, 10.1–20 ϫ, 20.1–30 ϫ, and Ͼ30 ϫ 106 spermatozoa, and categories for cycles were 1, 2, 3, and Ն4 treatment cycles.
Infertility type, duration of infertility, and timing of IUI were also treated as categorical variables: primary or secondary infertility, Ͻ3 or Ն3 years and 24 –28 or 36 – 40 hours after Estimates of PR per cycle are presented in To explore the association between PR (dependent variable) and the independent variables (e.g., sperm count, female age), odds ratios (OR) were calculated by unconditional logistic regression analysis Odds ratios refer to amount of times that pregnancy risk increases/decreases for each cate- gory of the variable using the first category as the reference (OR ϭ 1). Thus, indicator variables for each category of the independent variables were automatically established. Odds ratios with 95% confidence intervals (95% CI) and P-values were estimated for the variables included in using the statistical program STATA The likelihood ratio statistic was used to evaluate the overall significance for each variable and the presence of linear trends.
Tests for trends were performed for each ordinal variable Ibe´rico. Predictors of pregnancy in homologous IUI. Fertil Steril 2004. after unfactorizing and adding it to a previous model, includ-ing potential confounders. The statistical tests were two-sided. To allow for comparisons with other studies, all vari- administration (14.9%), and infertility duration of Ͻ3 years ables of were included in the final model.
In a final multivariate analysis and after controlling for the number of cycles and women’s age the three Female age ranged from 18 to 43 years (mean Ϯ SD: 32.6 predictors of PR were the number of preovulatory follicles Ϯ 3.8). The overall PR per cycle was 9.2%. The multiple PR (PϽ.02), the motile sperm count (PϽ.01), and the infertility was 8.6%, all of them twins. Miscarriage, ectopic, and still- duration (Pϭ.06). Ovarian response with two or more pre- birth rates were 11.8%, 5.4%, and 1.1%, respectively. The ovulatory follicles produced better PRs than a monofollicu- highest PRs per cycle were observed among those couples lar response Although a positive linear trend was with a sperm count after preparation of Ͼ30 ϫ 106 (15.3%), observed with increasing ORs for IUI with two and three three preovulatory follicles of Ͼ15 mm on the day of hCG follicles (2.01 and 2.89, respectively) with respect to IUI 1310 Ibe´rico et al.
Predictors of pregnancy in homologous IUI ing linear trend observed for sperm count was statistically significant (P-trend Ͻ.001). The OR decreased when infer-tility duration was Ն3 years (Pϭ.07, OR ϭ 0.65, 95% CI, Adjusted odds ratiosa in patients undergoing homologous intrauterine insemination according todifferent variables.
Overall, female age was not significantly associated with PR in multivariate analysis (Pϭ.18). The highest OR for PRs was observed among the youngest women, and the lowest, among women between 30 and 34 years of age although no linear decreasing trend in ORs was apparent by increasing age category. Women 40 years and older pre- sented slightly lower ORs than the youngest women but higher than the women 30 –34 years old although estimates did not reach statistical significance and were based on only Most pregnancies occurred within the two first IUI cycles (69 out of 93, i.e., 74.2% of pregnancies), with a PR close to 10%. Although lower ORs for PRs were observed on and after the third cycle, no statistically significant association Timing of single insemination was not associated with pregnancy, although the OR for PR was 28% higher when insemination was performed 24 –28 hours after the day of hCG administration rather than 36 – 40 hours. Type of infer- tility, dominant follicle diameter, ovulatory ovarian side, and catheter type were not associated to PR.
DISCUSSION
In this study, a multifollicular ovarian response to hMG, a high motile spermatozoa count inseminated, and a short infertility duration were the variables associated with the highest PR after controlling for other variables, including the number of cycles and female age. The positive association between PR and the number of preovulatory follicles (Ͼ15 mm) on hCG day is in accordance with that reported in other studies In this sense, the higher PR observed among women with a dominant follicle Ն20 mm, although nonsig- nificant, could be along the lines of previous findings and due in part to a more intense ovarian stimulation. However, contrary to other studies we found no association between PR and ovulatory ovarian side.
With respect to the sperm characteristics, higher concen- Odds ratios for pregnancy were adjusted by including all variables of the table. They refer to times that pregnancy risk increases/decreases for each tration and better quality after sperm preparation were con- category of the variable using the first category as the reference (OR ϭ 1).
sistently related to improved PRs after IUI In this b P-value from the Wald test.
sense, the PR observed among those with sperm count higher Ibe´rico. Predictors of pregnancy in homologous IUI. Fertil Steril 2004. than 30 ϫ 106 was on average double that of the middlecategories (5.1–30 ϫ 106) and almost five times higher thanin the lowest category (Յ5 ϫ 106). Therefore, our results with one follicle (P-trend Ͻ.001), the OR for IUI with Ն would not support the suggested sperm count of Ͻ10 ϫ 106 as the threshold value for IUI treatment of infertile couples Compared with the insemination with a sperm count Ͼ30 since still acceptable PRs may be observed with ϫ 106, insemination with 20.1–30, 10.1–20, 5.1–10, and Յ5 sperm count between 5.1 and 10 ϫ 106. However, the ϫ 106 sperm progressively decreased the PR, from 15.3% in considerable decrease in PR with Յ5 ϫ 106 would be very the highest category to 3.6% in the lowest one. The decreas- difficult to counterbalance by the presence of other favorable FERTILITY & STERILITY௡
factors such as a multifollicular response or a short duration inseminations in relation to hCG day needed to optimize the IUI success are important issues and are yet to be determinedIn a recent review of randomized studies comparing As in other studies, we observed that a decreased PR was double versus single IUI regimens, a beneficial effect of associated with longer infertility duration Although the double insemination regimen with respect to single insemi- precise limits of infertility duration for recommending IUI nation was observed in two studies, although the overall have not been clearly established, according to our data, PR effect measure was not statistically significant. In accordance may be seriously compromised when it is Ն3 years unless a with this review and one additional study showing no ben- multifollicular ovarian response and a high sperm concen- eficial effect of double versus single insemination we must conclude that the data are not conclusive enough to Cycle fecundity has been reported to be relatively con- enable us to offer advice regarding clinical practice yet. In stant for the first three to six cycles in accordance with this sense, we used only one single insemination per cycle infertility etiology although decreasing PRs with an indistinctly within the 24 –28 or 36 – 40 hours after hCG day, increased number of treatment cycles have also been shown and although we found a better PR among those patients Accordingly, most of our pregnancies (74.2%) were inseminated in the first 24 –28 hours after hCG administra- obtained within the first two treatment cycles, and the pos- tion, results were not statistically significant and no defini- sibility of achieving a pregnancy beyond the second one was lower, regardless of any other factors, although not statisti-cally significant. Taking into account also that we found no Finally, we must mention the importance of counseling correlation between potential IUI success and past fertility patients about the cost-benefit ratio of assisted reproductive (infertility type), we have no data to support withholding IUI techniques, particularly for making decisions about the dif- after three cycles, as suggested by others ferent treatment options. To minimize the psychologicaldistress associated with less effective procedures, some pa- The incidence of high-order multiple pregnancies, defined tients and centers opt for more sophisticated and expensive as a pregnancy involving three or more fetuses, is a known procedures such as IVF before considering IUI even adverse effect of the induction of ovulation with gonadotro- though IUI cycles are much less expensive than IVF cycles.
pin, and it has been correlated with the number of growing If the average cost per pregnancy were to be estimated follicles on the day of hCG administration The according to our PR (9.2%), assuming a €500 average cost proportion of multiple pregnancies in our study was low per treatment cycle of hMG ϩ IUI, then 10.8 cycles should (8.6%), all of them twins. We reported no high-order mul- be needed to get a pregnancy, and some €5.400 would be the tiple pregnancies, which could be in part related to the low average cost for a pregnancy. A much higher average cost proportion of cycles (5.4%) with four or more induced per pregnancy should be expected if our patients were re- follicles Ͼ15 mm. In this sense, if we applied the data ferred for IVF treatment as a result of its higher cost per reported by Dickey et al. with seven high-risk multiple treatment cycle (about €3,000/cycle). In addition, the higher pregnancies among 299 cycles with four or more induced risk of multiple pregnancies with the added costs during follicles (37.2% of total hMG cycles), we should expect pregnancy, delivery, and the neonatal period of the IVF about one high-risk multiple pregnancy. However, since we treatment would further favor the cost-effectiveness of IUI have a low number of observations we cannot make defin- In conclusion, our results suggest that hMG/hCG/IUI may Several published trials have underlined the importance be a useful treatment for infertile couples even in the pres- of age in every aspect of natural and artificial reproduction ence of some unfavorable circumstances such as monofol- techniques, and an age-related decline in female fecundity licular ovarian response and long infertility duration, al- has been well documented, particularly in women undergo- though it should be probably reconsidered when the sperm ing IUI Although we found lower PRs among count is Յ5 ϫ 106. As expected, a multifollicular ovarian women 30 –39 years old than in those younger than 30 years response (up to three follicles) produced a better treatment of age, no decline was found among women 40 – 43 years outcome than monofollicular response, with no apparent old, and overall, age was not significantly associated with increased risk of multiple pregnancies; increasing PRs were IUI success. In this sense, some studies have found that also observed for higher sperm count, with satisfactory PRs advanced female age had no negative effect on IUI success only above 5 ϫ 106, and a lower although nonsignificant PR and satisfactory PRs have been obtained among was observed with longer infertility duration (Ն3 years).
women 40 – 42 years old similar to those found in our Contrary to other studies, we did not find female age to be a major determinant of PRs, although this result may need Timing of insemination around ovulation has been sug- further research. Thus, we believe that our results may be gested to be the most important variable affecting the suc- helpful for better counselling and selection of couples un- cess of IUI treatment. The optimal timing and number of dertaking infertility treatment, thereby increasing the success 1312 Ibe´rico et al.
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