Salivary testosterone concentrations in pubertal ICSI boys compared with spontaneously conceived boys

Pubertal development and reproductive hormone levels of singleton ICSI offspring in adolescence: results of a prospective controlled study

STUDY QUESTION

Are there any differences in the pubertal development and reproductive hormone status during adolescence between singletons following ICSI therapy or spontaneous conception (SC)?

SUMMARY ANSWER

Pubertal development and reproductive hormone levels are largely similar between ICSI and SC adolescents, except for a tendency towards lower inhibin B levels as well as significantly higher estradiol levels and a lower testosterone-to-estradiol-ratio in male adolescents.

WHAT IS KNOWN ALREADY

Previous data are scarce and partly inconclusive regarding pubertal development in female ICSI adolescents as well as demonstrating a tendency towards lower inhibin B serum levels in male ICSI offspring.

STUDY DESIGN, SIZE, DURATION

Prospective controlled study including 274 singleton ICSI-conceived adolescents (141 girls, 133 boys) followed up for the third time, and 273 SC controls (142 girls, 131 boys) from seven German registration offices (Aachen, Eichstätt, Erfurt, Lübeck, Hamburg, Heidelberg and Schwerin).

PARTICIPANTS/MATERIALS, SETTING, METHODS

Pubertal development assessed by Tanner staging (breast, genital and pubic hair development), age at menarche and reproductive hormone levels were analyzed in ICSI and SC adolescents at the mean age of 16.5 years. Differences were analyzed by multinomial regression (Tanner stages) or t test and linear regression for hormonal assessments.

MAIN RESULTS AND THE ROLE OF CHANCE

Both female and male ICSI and SC adolescents showed adequate pubertal maturation according to their age, and the mean age at menarche (at 12.7 versus 12.8 years) was similar. Tanner stages as well did not display any relevant or significant differences between the groups. Reproductive hormone levels in female adolescents not using hormonal contraception were largely similar before and after adjustment for several factors such as preterm birth, Tanner stages, BMI or physical activity. In male ICSI adolescents, a tendency towards lower inhibin B (−14.8 pg/ml, 95% CI: −34.2 to 4.6 pg/ml), significantly higher estradiol (2.6 ng/l, 95% CI: 0.0 to 5.2 ng/l) and a significantly lower testosterone-to estradiol ratio (−0.047, 95% CI: −0.089 to −0.004) was found.

LIMITATIONS, REASONS FOR CAUTION

The all-over response rate and the willingness to participate in the blood test and medical examination were very low in the control group. Participating control families may have greater health awareness, and selection bias cannot be ruled out. Hormonal data in the females were measured irrespective of the cycle day and restricted to those not using hormonal contraception. Some parameters from the questionnaire data such as usage of hormonal contraception might suffer from reporting bias. As this is an observational study, we can draw only limited causal conclusions from the findings.

WIDER IMPLICATIONS OF THE FINDINGS

Differences in male reproductive hormones may indicate altered testicular function. However, at this time possible consequences for later reproductive success are unknown.

STUDY FUNDING/COMPETING INTEREST(S)

DFG research grant KA 1643/4-1. The authors declare no conflict of interest.

Endocrine and reproductive profile of boys and young adults conceived after ICSI

PURPOSE OF REVIEW

The impact of intracytoplasmic sperm injection (ICSI), on the reproductive health of the offspring is largely unknown. Here we provide a comprehensive overview of the endocrine and reproductive profile in boys and young male adults born after ICSI using ejaculated spermatozoa alleviating male factor infertility in their parents.

RECENT FINDINGS

Levels of testosterone, anti-Müllerian hormone and inhibin B were found comparable in prepubertal and pubertal boys conceived by ICSI when compared with levels in boys conceived spontaneously. Also, at young adulthood, mean levels of reproductive hormones did not differ from control peers. However, semen analysis showed significantly lower sperm concentration, total sperm count and total motile sperm count when compared with controls. Furthermore, the risk of having sperm concentration and sperm count below the reference values was increased in ICSI offspring while sperm parameters did not correlate in paired father-son semen analysis.

SUMMARY

Although endocrine gonadal function was normal at puberty, exocrine function at young adulthood was not. We observed decreased semen quality and quantity in young adults conceived by ICSI performed to circumvent male factor infertility. The possibility of transgenerational transmission of impaired spermatogenesis after ICSI needs further investigation.

The safety of intracytoplasmic sperm injection and long-term outcomes

The pioneering of intracytoplasmic sperm injection (ICSI) approximately 25 years ago revolutionized the treatment of infertile couples. Today, ICSI remains an indispensable part of assisted reproductive treatments (ART) and has resulted in the birth of millions of babies. The 25th anniversary of ICSI marks a chronologic landmark in its evolving history. This landmark also serves as an opportunity to thoroughly appraise the safety of ICSI and analyze the long-term outcomes of ICSI-conceived children. In this review, we collate and analyze salient data accrued over the past 25 years pertaining to the long-term safety of ICSI and ICSI conceptions. We also evaluate the effects of ICSI on the perinatal outcomes, congenital malformation rates, cognitive development and reproductive health of ICSI-conceived neonates, children, adolescents and adults, respectively. In doing so, we also highlight the existence of potential confounders and biases that frequently obscure the interpretation of clinical follow-up studies.

Intracytoplasmic sperm injection: state of the art in humans

Among infertile couples, 25% involve both male and female factors, while male factor alone accounts for another 25% due to oligo-, astheno-, teratozoospermia, a combination of the three, or even a complete absence of sperm cells in the ejaculate and can lead to a poor prognosis even with the help of assisted reproductive technology (ART). Intracytoplasmic sperm injection (ICSI) has been with us now for a quarter of a century and in spite of the controversy generated since its inception, it remains in the forefront of the techniques utilized in ART. The development of ICSI in 1992 has drastically decreased the impact of male factor, resulting in millions of pregnancies worldwide for couples who, without ICSI, would have had little chance of having their own biological child. This review focuses on the state of the art of ICSI regarding utility of bioassays that evaluate male factor infertility beyond the standard semen analysis and describes the current application and advances in regard to ICSI, particularly the genetic and epigenetic characteristics of spermatozoa and their impact on reproductive outcome.

Reproductive hormones of ICSI-conceived young adult men: the first results

STUDY QUESTION

Are reproductive hormone levels (FSH, LH, inhibin B and testosterone) in male offspring conceived by ICSI because of male infertility comparable with those from peers born after spontaneous conception?

SUMMARY ANSWER

In this cohort of 54 young men conceived by ICSI because of male-factor infertility, mean and median reproductive hormone levels were found to be comparable with results from spontaneously conceived peers, but ICSI-conceived men were more likely to have low inhibin B (<10th percentile) and high FSH (>90th percentile) levels.

WHAT IS KNOWN ALREADY

Since the worldwide oldest ICSI offspring have recently reached young adulthood, their reproductive health can now be investigated. This typically involves semen analysis and a hormonal profiling including the measurement of FSH, LH, inhibin B and testosterone. Circulating levels of FSH and inhibin B are generally known as markers of the exocrine function of the testis, i.e. spermatogenesis, while LH and testosterone reflect its endocrine function. We have previously observed a normal pubertal development and comparable levels of inhibin B and testosterone among pubertal ICSI boys when compared to spontaneously conceived peers. However, at present, information on the gonadal function of ICSI offspring in adulthood is still lacking.

STUDY DESIGN, SIZE, DURATION

This study, conducted between March 2013 and April 2016 at the UZ Brussel, is part of a larger follow-up project focusing on reproductive and metabolic health of young adults between 18 and 22 years and conceived after ICSI because of male infertility. The ICSI men are part of a longitudinally followed cohort while the spontaneously conceived controls were recruited cross-sectionally.

PARTICIPANTS/MATERIALS, SETTING, METHODS

Results of a single fasting blood sample from 54 young adult ICSI men were compared to that of 57 spontaneously conceived peers. Reproductive hormone analysis involved FSH, LH, testosterone and inhibin B measurement. Furthermore, the association between their reproductive hormones and their sperm parameters was examined. Data were analyzed by multiple linear and logistic regression adjusted for covariates.

MAIN RESULTS AND THE ROLE OF CHANCE

ICSI men had comparable mean levels of FSH, LH, testosterone and inhibin B in comparison to spontaneously conceived counterparts, even after adjustment for confounders, such as age, BMI and season. Young ICSI-conceived men were more likely to have inhibin B levels below the 10th percentile (<125.2 ng/l; Adjusted Odds Ratio (AOR) 4.0; 95% CI: 0.9-18.4; P = 0.07) compared with spontaneously conceived peers and were more likely to have FSH levels above the 90th percentile (>5.5 IU/L; AOR 3.3; 95% CI: 0.9-11.9; P = 0.06) compared with spontaneously conceived peers, but neither difference reached statistical significance. FSH, LH and inhibin B, but not testosterone, levels were significantly associated with sperm concentration and total sperm count.

LIMITATIONS, REASONS FOR CAUTION

The main limitation is the small study population. Furthermore, the results of this study should be interpreted according to the background of the participants: all subjects in our study group were conceived by ICSI because of severe male infertility and hence the results cannot be generalized to all ICSI offspring because the indications for performing ICSI have since been widened.

WIDER IMPLICATIONS OF THE FINDINGS

These first results in a small group of ICSI men show reassuring reproductive hormonal levels. However, larger studies are required to confirm our results. Since inhibin B and FSH are consistently correlated with semen characteristics, we would suggest that the reproductive status of young adults conceived by ICSI is explored with a hormonal assessment given its easier acceptance compared to semen sampling.

STUDY FUNDING/COMPETING INTERESTS

This study was supported by Methusalem grants and by grants from Wetenschappelijk Fonds Willy Gepts, all issued by the Vrije Universiteit Brussel (VUB). A grant from the Belgian Society for Pediatric Endocrinology and Diabetology was received for this project. All co-authors, except M.B. and H.T., declare no conflict of interest. M.B. has received consultancy fees from MSD, Serono Symposia and Merck. The Universitair Ziekenhuis Brussel (UZ Brussel) and the Centre for Medical Genetics have received several educational grants from IBSA, Ferring, Organon, Shering-Plough, Merck for establishing the database for follow-up research and organizing the data collection. The institution of HT receives research grants from the 'Research Fund of Flanders' (FWO), an unconditional grant from Ferring for research on testicular stem cells and research grants from Ferring, Merck, MSD, Roche, Besins, Goodlife and Cook for several research projects in female infertility. H.T. has received consultancy fees from Finox, Abbott and ObsEva for research projects in female infertility.

TRIAL REGISTRATION NUMBER

N/A.

Semen quality of young adult ICSI offspring: the first results

STUDY QUESTION

What is the semen quality of young adult men who were conceived 18-22 years ago by ICSI for male infertility?

SUMMARY ANSWER

In this cohort of 54 young adult ICSI men, median sperm concentration, total sperm count and total motile sperm count were significantly lower than in spontaneously conceived peers.

WHAT IS KNOWN ALREADY

The oldest ICSI offspring cohort worldwide has recently reached adulthood. Hence, their reproductive health can now be investigated. Since these children were conceived by ICSI because of severe male-factor infertility, there is reasonable concern that male offspring have inherited the deficient spermatogenesis from their fathers. Previously normal pubertal development and adequate Sertoli and Leydig cell function have been described in pubertal ICSI boys; however, no information on their sperm quality is currently available.

STUDY DESIGN, SIZE, DURATION

This study was conducted at UZ Brussel between March 2013 and April 2016 and is part of a large follow-up project focussing on reproductive and metabolic health of young adults, between 18 and 22 years and conceived after ICSI with ejaculated sperm. Results of both a physical examination and semen analysis were compared between young ICSI men being part of a longitudinally followed cohort and spontaneously conceived controls who were recruited cross-sectionally.

PARTICIPANTS/MATERIALS, SETTING, METHOD

Results of a single semen sample in 54 young adult ICSI men and 57 spontaneously conceived men are reported. All young adults were individually assessed, and the results of their physical examination were completed by questionnaires. Data were analysed by multiple linear and logistic regression, adjusted for covariates. In addition, semen parameters of the ICSI fathers dating back from their ICSI treatment application were analysed for correlations.

MAIN RESULTS AND THE ROLE OF CHANCE

Young ICSI adults had a lower median sperm concentration (17.7 million/ml), lower median total sperm count (31.9 million) and lower median total motile sperm count (12.7 million) in comparison to spontaneously conceived peers (37.0 million/ml; 86.8 million; 38.6 million, respectively). The median percentage progressive and total motility, median percentage normal morphology and median semen volume were not significantly different between these groups. After adjustment for confounders (age, BMI, genital malformations, time from ejaculation to analysis, abstinence period), the statistically significant differences between ICSI men and spontaneously conceived peers remained: an almost doubled sperm concentration in spontaneously conceived peers in comparison to ICSI men (ratio 1.9, 95% CI 1.1-3.2) and a two-fold lower total sperm count (ratio 2.3, 95% CI 1.3-4.1) and total motile count (ratio 2.1, 95% CI 1.2-3.6) in ICSI men compared to controls were found. Furthermore, compared to men born after spontaneous conception, ICSI men were nearly three times more likely to have sperm concentrations below the WHO reference value of 15 million/ml (adjusted odds ratio (AOR) 2.7; 95% CI 1.1-6.7) and four times more likely to have total sperm counts below 39 million (AOR 4.3; 95% CI 1.7-11.3). In this small group of 54 father-son pairs, a weak negative correlation between total sperm count in fathers and their sons was found.

LIMITATIONS, REASONS FOR CAUTION

The main limitation is the small study population. Also, the results of this study where ICSI was performed with ejaculated sperm and for male-factor infertility cannot be generalized to all ICSI offspring because the indications for ICSI have nowadays been extended and ICSI is also being performed with non-ejaculated sperm and reported differences may thus either decrease or increase.

WIDER IMPLICATIONS OF THE FINDINGS

These first results in a small group of ICSI men indicate a lower semen quantity and quality in young adults born after ICSI for male infertility in their fathers.

STUDY FUNDING/COMPETING INTERESTS

This study was supported by Methusalem grants and by grants from Wetenschappelijk Fonds Willy Gepts, all issued by the Vrije Universiteit Brussel (VUB). All co-authors except M.B. and H.T. declared no conflict of interest. M.B. has received consultancy fees from MSD, Serono Symposia and Merck. The Universitair Ziekenhuis Brussel (UZ Brussel) and the Centre for Medical Genetics have received several educational grants from IBSA, Ferring, Organon, Shering-Plough and Merck for establishing the database for follow-up research and organizing the data collection. The institution of H.T. has received research grants from the Research Fund of Flanders (FWO), an unconditional grant from Ferring for research on testicular stem cells and research grants from Ferring, Merck, MSD, Roche, Besins, Goodlife and Cook for several research projects in female infertility. H.T. has received consultancy fees from Finox, Abbott and ObsEva for research projects in female infertility.

Safety of intracytoplasmic sperm injection

Early follow-up studies of IVF children showed that the frequency of birth anomalies resembled those arising with natural conception. More detailed analyses confirmed these findings, reinforcing the concept of the preimplantation period as teratologically "safe." The use of intracytoplasmic sperm injection (ICSI) to achieve fertilization introduced another variable.ICSI's safety has often been criticized because the fertilizing spermatozoon neither binds to the zona pellucida nor fuses with oolemma. Bypassing these physiologic steps together with the arbitrary selection of the spermatozoon has been reason for concern. Thus far, ICSI offspring undergoing adolescence and beyond has provided sufficient information to reassure these qualms. In fact, the health of the offspring generated through ICSI, once taken into consideration the gestational order, the age and the genetic makeup of the couples are generally reassuring.

Long-term follow-up of children conceived through assisted reproductive technology

Children conceived via assisted reproductive technologies (ART) are nowadays a substantial proportion of the population. It is important to follow up these children and evaluate whether they have elevated health risks compared to naturally conceived (NC) children. In recent years there has been a lot of work in this field. This review will summarize what is known about the health of ART-conceived children, encompassing neonatal outcomes, birth defects, growth and gonadal developments, physical health, neurological and neurodevelopmental outcomes, psychosocial developments, risk for cancer, and epigenetic abnormalities. Most of the children conceived after ART are normal. However, there is increasing evidence that ART-conceived children are at higher risk of poor perinatal outcome, birth defects, and epigenetic disorders, and the mechanism(s) leading to these changes have not been elucidated. Continuous follow-up of children after ART is of great importance as they progress through adolescence into adulthood, and new ART techniques are constantly being introduced.

Pubertal development in ICSI children

BACKGROUND

To date, information on the pubertal development of adolescents born after ICSI is scarce, since the very first cohort is only now reaching young adulthood. In this study, pubertal development at the age of 14 was characterized in a longitudinally followed cohort of ICSI-conceived teenagers and compared with that of a spontaneously conceived (SC) control group.

METHODS

Pubertal development was assessed by Tanner staging (breast, genital and pubic hair development) and age at menarche in 217 singleton ICSI-conceived children (116 boys, 101 girls) and 223 SC peers (115 boys, 108 girls). ICSI teenagers were part of a previously published cohort followed since birth; controls were a cross-sectional sample recruited from schools. Differences in pubertal development between ICSI and SC children were analyzed with logistic regression of current status data.

RESULTS

Mean age at menarche was similar in ICSI and SC girls (13.1 ± 1.2 versus 13.1 ± 1.4 years; P = 0.8). Breast developmental at the age of 14 years was less advanced in ICSI females compared with SC females, even after adjustment for demographic (age, BMI), genetic (maternal age at menarche), social (maternal educational level) and early life factors (birthweight, gestational age and maternal parity) [odds ratio (OR) 0.5; 95% confidence interval (CI) 0.3-0.8]. After adjustment, genital development in the 14-year-old boys was comparable in the ICSI and SC groups (OR 1.1; 95% CI 0.7-1.8), pubic hair development was comparable in the ICSI and SC groups, for both males (OR 0.9; 95% CI 0.7-1.6) and females (OR 0.7; 95% CI 0.4-1.3).

CONCLUSIONS

We found that pubertal development, characterized by menarche, genital development in males and pubic hair development in males and females, was comparable in the ICSI and SC groups. Breast developmental was less advanced in ICSI females compared with SC peers, even after adjustment for known potential confounders. In order to confirm that progression through subsequent stages of pubertal development occurs on a timely basis in ICSI teenagers, long-term follow-up studies up to adulthood are required.

Childhood outcomes of assisted reproductive technology

There is a large population of children conceived via assisted reproductive technology (ART), which continues to increase worldwide, without a clear understanding of associated long-term outcomes. ART children are more likely to be the result of multiple pregnancies, and thus to be born prematurely or low birthweight. There is growing evidence that ART children are phenotypically and biochemically different from naturally conceived children, but the mechanism(s) leading to these changes have not been elucidated. There is a possible increased risk of rare imprinted gene disorders in these children. However, it remains unclear whether more subtle changes in DNA methylation occur commonly, leading to differences in gene expression and phenotype in ART children. Although an increased risk of cancer among ART children has been reported, the role of ART in the development of cancer has not been demonstrated. Further research and ongoing surveillance of ART children is essential to better understand the possible effects of ART on the long-term health of this population.