Abnormal sperm morphology is highly predictive of pregnancy outcome during controlled ovarian hyperstimulation and intrauterine insemination

Effect of Sperm Morphology on Pregnancy Success via Intrauterine Insemination: A Systematic Review and Meta-Analysis

PURPOSE

Men with abnormal sperm morphology are often counseled that natural conception and intrauterine insemination are ineffective, and in vitro fertilization is the only option. Our objective was to determine the effect of sperm morphology on the pregnancy success of intrauterine insemination.

MATERIALS AND METHODS

We systematically searched for studies published prior to January 2017 that 1) reported ultrasound verified clinical pregnancies per intrauterine insemination cycle, 2) assessed sperm morphology using the Kruger strict criteria and 3) described morphology at the greater than 4% and 4% or less and/or the 1% or greater and less than 1% thresholds. In all studies mean female age was between 25 and 40 years and mean total motile sperm count was greater than 10 million. Estimates were pooled using random effects meta-analysis.

RESULTS

Data were extracted from 20 observational studies involving a total of 41,018 cycles. When comparing men at the greater than 4% and 4% or less thresholds, the rate of ultrasound verified pregnancy per intrauterine insemination cycle was not statistically or clinically different (14.2% vs 12.1%, p = 0.06) and the risk difference was 3.0% (95% CI 1.4-4.6), indicating 3.0 additional pregnancies per 100 intrauterine insemination cycles. When comparing men at the 1% or greater and the less than 1% thresholds, there were no statistical or clinical differences in the rate of ultrasound verified pregnancy per cycle of intrauterine insemination (14.0% vs 13.9%, p = 0.97) or in the risk difference (1.6%, 95% CI -4.5-7.6).

CONCLUSIONS

There appears to be no clinical difference in intrauterine insemination pregnancy success among men with normal and abnormal sperm morphology when accounting for total motile sperm count and female age. Abnormal sperm morphology alone should not exclude couples from attempting intrauterine insemination.

Assessment of spermatozoa in fertile alpaca (Vicugna pacos) males: Study of sperm head morphometry using a nonautomated digital method and sperm morphology based on strict criteria

Although computer-assisted systems for sperm morphometry and morphological analysis are important tools in the study of male fertility, their use in extensive systems in alpacas is limited by factors such as the expense of equipment and the high altitudes of the Andean region. The objectives of this study were to evaluate alpaca sperm head morphometry using a nonautomated digital method and determine the frequency of sperm abnormalities based on strict criteria for sperm morphology in fertile male alpacas. Ejaculates (n = 15) from seven alpacas were collected, and sperm smears stained with modified Papanicolaou were processed. For morphometric analysis, 3,000 sperm (200 cells/sample) images were captured at 400× magnification and Quick Photo MICRO 3.0 software was used for manual measurement of basic (sperm head length, width, perimeter and area) and derived variables (ellipticity, shape factor, elongation and regularity). For morphology assessment, smears were observed at 1000× magnification according to WHO and strict criteria. Average morphometric parameters were length 5.48 μm, width 2.99 μm, perimeter 13.62 μm, area 12.43 μm² , ellipticity 1.86, shape factor 1.20, elongation 0.29 and regularity 1.05. Significant between-individual and within-individual differences were found in morphometric parameters. Based on morphometric study, sperm heads were classified as elliptical or normal (49%), long (18%), short (2%), pyriform (12%), round (9%), large (6%) and small (4%). Morphological analysis found no additional sperm head defects in 49% of normal sperm obtained by morphometry, although a 4% incidence of neck/mid-piece defects and a 16% incidence of principal-piece defects were found. We conclude that sperm head morphometry assessment in fertile alpacas using a nonautomated digital method is feasible, and that defects in sperm heads constitute the main morphological alteration (>50% of the sperm population), based on WHO and strict criteria.

Role of Abnormal Sperm Morphology in Predicting Pregnancy Outcomes

The evaluation of strict morphology for predicting successful pregnancy has been controversial, nevertheless remains an essential component of semen analysis. Patients with teratozoospermia (abnormal strict morphology) have traditionally been counseled to undergo assisted reproduction. However, recent studies suggest that patients with abnormal sperm morphology alone should not be precluded from attempting natural conception before undergoing assisted reproduction. The goal of this review is to provide an update on the evaluation of sperm morphology for prognosis in assisted reproductive techniques such as intrauterine insemination and in vitro fertilization with or without intracytoplasmic sperm injection. Additionally, we propose a logical approach to the evaluation of a patient with teratozoospermia seeking fertility treatment.

Value of the sperm chromatin dispersion test in predicting pregnancy outcome in intrauterine insemination: a blind prospective study

BACKGROUND

Sperm DNA integrity has been used as a new marker of sperm quality in the prediction of pregnancy. Nevertheless, no previous study has been performed by analysing the same samples that were employed in assisted reproduction. The main objective of this work was to correlate sperm chromatin dispersion (SCD), measured by the SCD test, with semen parameters and pregnancy outcome in intrauterine insemination (IUI).

METHODS

A total of 100 semen samples obtained from males of couples undergoing IUI were analysed by the SCD test before and after swim-up, and the results were correlated with semen parameters and pregnancy outcome.

RESULTS

SCD was negatively correlated with sperm motility in both ejaculated and processed semen. Sperm recovered by swim-up did not show a significant improvement in DNA integrity. No correlation was found between SCD and pregnancy outcome in IUI.

CONCLUSIONS

DNA dispersion, as measured by the SCD test, is not correlated with pregnancy outcome in IUI.

Impact of isolated teratozoospermia on the outcome of intrauterine insemination

One thousand six hundred forty-one IUI cycles performed in 615 couples were categorized, depending on the semen analysis of the male partner, in three groups of: normozoospermia, teratozoospermia, and male factor infertility. Clinical pregnancies and live births per cycle were significantly decreased in the teratozoospermia group when compared to the normozoospermia group, with the exception of the first IUI attempt (comparable outcomes), whereas the cumulative live birth rate after four IUI attempts was significantly lower in the teratozoospermia and male factor infertility groups.

The Use of Semen Parameters to Identify the Subfertile Male in the General Population

AIMS

To present a structured review of the literature published on semen parameters and in vivo fertility potential and to establish fertility/subfertility thresholds for sperm morphology using Tygerberg strict criteria, sperm concentration, and sperm motility.

METHOD

The published literature comparing fertile and subfertile populations between 1983 and 2002 was reviewed.

RESULTS

A total of 265 articles were identified by the sourcing methodology, but only four articles provided data that could be tabulated and analyzed. Using receiver-operating characteristics curves, morphology proved to be the best predictor of subfertility in 2 of the 4 articles, with concentration and motility also showing good predictive power. The thresholds calculated ranged between 4 and 10% for morphology, between 13.5 x 10(6)/ml and 34 x 10(6)/ml for concentration, and between 32 and 52% for motility. A second set of much lower thresholds was calculated in three of the articles using either a 15 or 50% prevalence of subfertility in the population or the tenth percentile of the fertile population. The adjusted thresholds were between 3 and 5% for morphology, between 9 x 10(6)/ml and 20 x 10(6)/ml for concentration, and between 20 and 30% for motility.

CONCLUSIONS

Because these lower thresholds have a much higher positive predictive value, we suggest that thresholds of <5% normal sperm morphology, a concentration <15 x 10(6)/ml, and a motility <30% should be used to identify the subfertile male. The lower threshold for morphology also fits in vitro fertilization and intrauterine insemination data calculated previously. Using the parameters in combination increases the clinical value of semen analysis.

Prediction of pregnancy by intrauterine insemination using CASA estimates and strict criteria in patients with male factor infertility

This study was performed to predict pregnancy by intrauterine insemination (IUI) using computer-aided sperm analysis (CASA) estimates and strict criteria in patients with male factor infertility. IUI was performed in 682 cycles on 160 male factor infertile patients. Semen examinations were carried out by CASA and strict criteria before and after sperm preparation using continuous-step density gradient centrifugation. Receiver operating characteristics (ROC) curves were constructed for assessment of the effectiveness of each individual parameter in predicting pregnancy by IUI. A clinically acceptable threshold was calculated when sensitivity plus specificity were maximum. The average cycle of IUI performed was 4.3 +/- 2.4. Pregnancy rate per cycle and per patient were 7.2% (49/682) and 28.1% (45/160), respectively. Using ROC curve, it was shown that normal sperm morphology assessed by the strict criteria before sperm separation and five parameters after sperm separation including rapid, progressive motility, average path velocity (VAP), curvilinear velocity (VCL), and straight line velocity (VSL) were able to predict pregnancy by IUI. Correlation between sperm parameters and pregnancy outcome was examined by the logistic regression model. In a multivariate analysis normal morphology before sperm separation >or=15.5% [odds ratio (OR) = 2.2, p = 0.02], rapid after sperm separation >or=25.5% [OR = 3.9, p = 0.029], and VCL after sperm separation >or=102.65 microm/sec [OR = 3.2, p = 0.002] were the parameters of predictive value for pregnancy outcome. Adjustment of the model for female age, female infertility factors, and the methods of ovulation induction did not change this finding, and the final model still had the same covariates. Pregnancy rates per cycle according to the number (0, 1, 2 and 3) of variables satisfied with the three parameters were 0% (0/110), 1.6% (3/183), 9.7% (21/217) and 15.1% (23/151), respectively. Three semen parameters including normal morphology before sperm separation, rapid and VCL after sperm separation were identified as predictors of pregnancy by IUI. These variables would be helpful when counselling patients before they make the decision to proceed with in vitro fertilization (IVF)/intracytoplasmic sperm injection (ICSI)-ET.

Isolated teratozoospermia and intrauterine insemination

OBJECTIVE

This study tests the hypothesis that IUI treatment in cases with isolated teratozoospermia (<10% normal forms using strict criteria, normal motility and normal count), results in a lower cumulative live birth rate compared to cases with normozoospermia.

DESIGN

A retrospective cohort study.

SETTING

An academic fertility center.

PATIENT(S)

Eight hundred seventy-two IUI cycles in 440 couples were analyzed.

INTERVENTION(S)

Couples (n = 440) were classified in three groups: normozoospermia (n = 213), isolated teratozoospermia (n = 104), and male factor infertility (n = 123).

MAIN OUTCOME MEASURE(S)

Live birth rate per cycle and cumulative live birth rate (CLBR).

RESULT(S)

The three groups were similar with regard to female age, female infertility factors, and ovarian response after hormonal stimulation. The overall CLBR after four cycles was 41.5%, and was significantly increased in the normozoospermic group (52.8%) when compared to the isolated teratozoospermia group (33.4%) and the male factor infertility group (31.4%).

CONCLUSION(S)

This study documents for the first time that the CLBR after four IUI cycles is significantly and similarly reduced in couples with isolated teratozoospermia as in couples with other sperm defects, when compared to couples with normozoospermia. As with couples with male factor infertility, couples with isolated teratozoospermia should be counseled about other treatment options such as IVF, as the CLBR after three IVF cycles is 70%-80% in our program.

Efficacy and pregnancy outcome of two methods of semen preparation for intrauterine insemination: a prospective randomized study

OBJECTIVE

To examine pregnancy outcome with two methods of semen preparation for intrauterine insemination (IUI).

DESIGN

Prospective and randomized study.

SETTINGS

Academic tertiary center.

PATIENT(S)

Three hundred eleven couples undergoing 676 consecutive cycles of assisted conception using IUI.

INTERVENTION(S)

Semen samples collected for IUI were randomized to wash only or density gradient centrifugation (DGC) processing.

MAIN OUTCOME MEASURE(S)

Various prepreparation and postpreparation semen parameters were used for IUI. The influence of the method of semen processing, and impact of various semen parameters and female factors on pregnancy were examined by receiver operating characteristics (ROC) curves, logistic regression, and life table analysis.

RESULT(S)

Of the 676 cycles, 88 resulted in conception leading to an overall clinical pregnancy rate of 13.0% per cycle and 28.3% per patient with a miscarriage rate of 34.0%. Eighty-eight percent of pregnancies occurred in the first three cycles of IUI and 95.5% within the first four cycles. The pregnancy rate for wash only was 11.6% (37 of 319) and the rate for DGC was 14.3% (51 of 356). However, in samples with <22 million motile sperm in the inseminate, pregnancy rates were 4% for wash and 18% for DGC. The woman's age for both methods and the percentage of sperm in the original semen with a velocity of > or =80 micro m/s for the wash method influenced pregnancy outcome.

CONCLUSION(S)

Although samples with an acceptable number of motile sperm can be processed efficiently by wash only, poor quality semen samples should be processed using DGC.

The use of novel semen quality scores to predict pregnancy in couples with male-factor infertility undergoing intrauterine insemination

The purpose of this study was to determine whether 2 new semen quality (SQ) scores could predict pregnancy in patients undergoing intrauterine insemination (IUI) for male-factor infertility and whether an overall score could help in counseling these couples with assisted reproductive technique (ART) options. Ninety-three couples with male-factor infertility were examined for semen analysis. Samples were prepared by density gradient separation (47% and 90%), and IUI was performed. On the basis of the 2 semen scores (SQ and relative quality [RQ]), the IUI-semen pregnancy score (IUI-SPS) was calculated. Of the 192 IUI cycles, 14% (27 of 192) resulted in pregnancy. Both prewash SQ and RQ scores were significantly related to pregnancy (P =.02 and P <.001), as was the postwash RQ score (P <.001). Of the IUI cycles in which the postwash RQ score was greater than 125, 40% (13 of 32) resulted in pregnancy compared to 9% of cycles (14 of 160) in which the postwash SQ score was less than 125. The prewash IUI-SPS score was significantly related to IUI-induced pregnancy (P <.001). Both the pre- and postwash SQ and RQ scores can predict pregnancy in male infertility patients undergoing IUI. Patients with an IUI-SPS less than 150 may be advised to seek in vitro fertilization (IVF), whereas those with an IUI-SPS greater than 150 may be advised to seek IUI.

Semen quality and intrauterine insemination

There is good evidence in literature that intrauterine insemination (IUI) is the best first line treatment and most cost-effective procedure for moderate male factor subfertility. It seems very difficult to identify individual semen parameters predicting the likelihood of pregnancy after IUI. This can be explained by a lack of standardization of semen analysis, but many other methodological variables may also influence IUI success rates such as the patient selection, type of ovarian stimulation and number of inseminations per cycle. A review of the literature confirmed that sperm morphology using strict criteria and the inseminating motile sperm count (IMC) after sperm preparation are the two most important sperm parameters to assess the real impact of semen quality on IUI outcome. A universal threshold level above which IUI can be performed with acceptable pregnancy rates has not been determined yet, although IUI success seems to be impaired with <5% normal spermatozoa and an IMC of <1 x 10(6). Until now, no method of sperm preparation has been shown to be superior with regard to pregnancy rate after IUI. Whether supplementation of culture media with substances such as antioxidants and platelet activating factor may improve the results remains the subject of further research.

Sperm morphology analysis using strict criteria as a prognostic factor in intrauterine insemination

The objective of this study was to investigate the predictive value of Kruger's criteria for sperm morphology on intrauterine insemination (IUI) outcome. A total of 209 infertile patients underwent 244 IUI treatment cycles. These include 75 couples (80 cycles) with teratozoospermia and 134 couples (164 cycles) with unexplained infertility. The pregnancy rates per IUI cycle were 3.8 (1/26), 18.5 (10/54) and 29.9% (49/164) in patients with sperm morphology with <4, 4-9 and >9% normal forms, respectively, according to Kruger's criteria. A statistical difference in outcome was seen between couples with <4 and >9% normal forms (p = 0.005). Although the difference in pregnancy rates between those with 4-9 and <4% normal forms was not statistically significant, the pregnancy rate for those with 4-9% normal forms was acceptable and still higher than in those with <4% normal forms. Therefore, we suggest that IUI is a reasonable first-line therapy for patients with sperm morphology >4% normal forms, while couples with <4% normal forms should be advised to use in vitro fertilization with intracytoplasmic sperm injection instead of IUI.

Comparison between human sperm preservation medium and TEST-yolk buffer on protecting chromatin and morphology integrity of human spermatozoa in fertile and subfertile men after freeze-thawing procedure

The aim of this study was to identify the detrimental effect of the freeze-thaw process on chromatin integrity and morphology of human spermatozoa, and to determine whether human sperm preservation medium (HSPM) or TEST-yolk buffer (TYB) offers a better protection to spermatozoa from cryodamage after the freeze-thaw procedure. Thirty-five semen samples obtained from couples childless because of male factor infertility (subfertile men, group 1) and 25 semen samples from healthy, normal volunteers of proven fertility (group 2) were included in the study. Each semen sample was divided into 2 parts, the first part was mixed with HSPM and the other with TYB (1:1), and frozen with a controlled slow-stage freezer, before plunging into liquid nitrogen. Twelve smears from each semen sample were made before (n = 4) and after (n = 8) the freeze-thaw process. Chromatin structure was evaluated after staining using the acridine orange (AO) test, whereas morphology was analyzed according to strict criteria. The mean percentage of spermatozoa that exhibited normal morphology and intact chromatin structure was decreased after freeze-thaw in all samples treated with HSPM or TYB in comparison with the value observed in the native semen samples of both groups. However, TYB preserved chromatin and morphology significantly better than HSPM did (9.3% +/- 5.6% and 88.7% +/- 11.2% vs. 7.8% +/- 4.2% and 85.5% +/- 12.5%, respectively). Therefore, TYB could be recommended as a first choice cryoprotectant for semen preservation in order to avoid extra chromatin structure damage and morphology alterations of spermatozoa not only for patients pursuing assisted reproduction, but also for donor samples.

Stepwise regression analysis to study male and female factors impacting on pregnancy rate in an intrauterine insemination programme

The aim of this study was to evaluate the impact of male and female factors on the pregnancy rate in an intrauterine insemination (IUI) programme. Data on 522 cycles were retrospectively studied. All patients 39 years or younger were included in the study where data were available on male and female diagnosis, as well as on ovulation induction methodology. Regression analysis was possible on 495 cycles to study different factors affecting the pregnancy rate per treatment cycle. Logistic regression identified variables which were related to outcome and were subsequently incorporated into a statistical model. The number of follicles was found to have a linear association with the risk ratio (chance) of pregnancy. The age of the woman was also found to have a linear (negative) association with pregnancy. The percentage motility and percentage normal morphology (by strict criteria) of spermatozoa in the fresh ejaculate were the male factors that significantly and independently predicted the outcome. Percentage motility > or = 50 was associated with a risk ratio of pregnancy of 2.95 compared to percentage motility < 50. Percentage normal sperm morphology > 14% was associated with a risk ratio of pregnancy of 1.8 compared to percentage normal morphology < or = 14%. Female patients with idiopathic infertility were divided into three groups according to normal sperm morphology. The pregnancy rate per cycle was 2.63% (1/38) for the P (poor) pattern group (0-4% normal forms), 11.4% (17/149) for the G (good) pattern group (5-14%), and 24% (18/75) for the N (normal) pattern group (> 14% normal forms). A female diagnosis of endometriosis or tubal factor impacted negatively on the probability of pregnancy (risk ratio of 0.17), compared with other female diagnoses. Male and female factors contribute to pregnancy outcome, but the clinician can influence prognosis by increasing the number of follicles, especially in severe male factor cases.

A study of semen parameters with emphasis on sperm morphology in a fertile population: an attempt to develop clinical thresholds

The aim of the study was to determine the semen parameters of a proven fertile population and to compare these parameters with that of a subfertile group in the same region. Sixty-nine fertile male patients were studied and compared with 93 patients recruited at an infertility clinic. A sub-sample of patients was matched according to age. Sixty-one were studied in the fertile group and 62 in the infertile group. Receiver operator characteristics analysis was done on the sub-sample. The threshold value of the progressive motility was 42% and it was the best parameter with sperm morphology to distinguish between the two groups. At 69% sensitivity and 67% specificity the sperm morphology threshold was 12% normal forms. If the positive and negative predictive value was used to screen the general population to identify the subfertile group, a 5% normal morphology threshold was indicated with 14% progressive motility, 30% motility and a concentration of 9x10(6)/ml or lower. The negative predictive values of the parameters were good and achieved 90% in most cases. The sensitivity of the semen parameters at the reported thresholds was poor and indicated a large overlap in the distributions of these variables in the fertile and infertile groups. To distinguish between the fertile and subfertile population, the most significant finding of this study was the progressive motility with a threshold level of 14%. The cut-off value of the sperm morphology (5%) in vivo was consistent with the previous publications in assisted reproduction programmes for sperm morphology.

Intrauterine insemination in male factor subfertility: significance of sperm motility and morphology assessed by strict criteria

The study was conducted to evaluate the results of IUI treatment in a homogenous group with male factor infertility, and to assess the correlation of sperm variables, including sperm morphology by strict criteria, with pregnancy achievement after IUI. A total of 108 couples with no apparent female aetiology for infertility underwent 264 intrauterine insemination treatment cycles. A comparison was made between the sperm variables in two groups in which the achievement of pregnancy differed. The percentage of motile spermatozoa, degree of motility and normal morphology (by strict criteria) were significantly higher in the pregnant group compared with that of the nonpregnant group. A significant difference in pregnancy rates per couple after intrauterine insemination was demonstrated among three groups according to the percentage of sperm morphology, i.e. poor (< 4%), fair (4-14%) or good (> 14%) (11.1%; 36.1% and 50.0%, respectively). Intrauterine insemination is a valid mode of treatment in cases with male infertility, provided that normal morphology by strict criteria is higher than 4%.