Fertility and infertility in aging women

What is driving the global decline of human fertility? Need for a multidisciplinary approach to the underlying mechanisms

An intense period of human population expansion over the past 250 years is about to cease. Total fertility rates are falling dramatically all over the world such that highly industrialized nations, including China and the tiger economies of SE Asia, will see their populations decline significantly in the coming decades. The socioeconomic, geopolitical and environmental ramifications of this change are considerable and invite a multidisciplinary consideration of the underlying mechanisms. In the short-term, socioeconomic factors, particularly urbanization and delayed childbearing are powerful drivers of reduced fertility. In parallel, lifestyle factors such as obesity and the presence of numerous reproductive toxicants in the environment, including air-borne pollutants, nanoplastics and electromagnetic radiation, are seriously compromising reproductive health. In the longer term, it is hypothesized that the reduction in family size that accompanies the demographic transition will decrease selection pressure on high fertility genes leading to a progressive loss of human fecundity. Paradoxically, the uptake of assisted reproductive technologies at scale, may also contribute to such fecundity loss by encouraging the retention of poor fertility genotypes within the population. Since the decline in fertility rate that accompanies the demographic transition appears to be ubiquitous, the public health implications for our species are potentially devastating.

Correlation of female age with outcome of IVF in a low-resource setting

OBJECTIVE

To determine the effect of female age on pregnancy outcome after in vitro fertilization/embryo transfer (IVF-ET).

METHODS

A prospective study was conducted involving 266 women who had IVF-ET at Nisa Fertility and Genetic Center, Abuja, Nigeria. All eligible consenting women were recruited to the study. The main outcome measure was clinical pregnancy. Data were analyzed using IBM SPSS Statistics version 25. P < 0.05 at 95% confidence intervals was taken as significant.

RESULTS

A total of 266 patients were recruited and included in the study; 104 pregnancies were recorded, giving an overall pregnancy rate of 39.1%. The age range of the patient was 26-43 years (mean age 33.9 ± 2.41 years) while the mean number of embryo transfers per patient was 2.2. The clinical pregnancy rate for women aged below 30 years was 69.4% while the pregnancy rate for patients aged 30-34 years, 35-39 years, and 40-43 years was 52.6%, 24.7%, and 9.4%, respectively (P < 0.0001).

CONCLUSION

The study found that the success rate of IVF-ET decreases significantly in women aged over 34 years. Women should be counseled about the age-related risk of infertility and referred to a fertility center as early as possible.

Prediction of Fertilization Disorders in the In Vitro Fertilization/Intracytoplasmic Sperm Injection: A Retrospective Study of 106,728 Treatment Cycles

Purpose

This study aimed to develop a risk prediction of fertilization disorders during the in vitro fertilization/intracytoplasmic sperm injection (IVF/ICSI).

Methods

A retrospective study was performed with 106,728 fresh embryo IVF/ICSI cycles from 2009 to 2019. Basic characteristics of patients, clinical treatment data, and laboratory parameters were involved. The associations between the selected variables and risks for low fertilization rate (LFR) and total fertilization failure (TFF) were investigated. Ordinal logistic regression and the receiver operating characteristic curves (ROCs) were used to construct and evaluate the prediction models.

Results

A total of 97,181 controls, 4,343 LFR and 5,204 TFF cases were involved in this study. The model based on clinical characteristics (the ages of the couples, women's BMI, types of infertility, ART failure history, the diminished ovarian reserve, sperm quality, insemination method, and the number of oocytes retrieved) had an AUC of 0.743 for TFF. The laboratory model showed that primary infertility, ART failure history, minimal-stimulation cycle/natural cycle, numbers of oocyte retrieved < 5, IVF, and Anti-Mullerian hormone (AMH) level < 1.1ng/ml are predictors of TFF, with an AUC of 0.742.

Conclusion

We established a clinical and a laboratory prediction model for LFR/TFF. Both of the models showed relatively high AUCs.

Effects of paternal age on human embryo development in in vitro fertilization with preimplantation genetic screening

OBJECTIVE

As paternal age increases, the quality of sperm decreases due to increased DNA fragmentation and aneuploidy. Higher levels of structural chromosomal aberrations in the gametes ultimately decrease both the morphologic quality of embryos and the pregnancy rate. In this study, we investigated whether paternal age affected the euploidy rate.

Methods

This study was performed using the medical records of patients who underwent in vitro fertilization (IVF) procedures with preimplantation genetic screening (PGS) from January 2016 to August 2017 at a single center. Based on their morphological grade, embryos were categorized as good- or poor-quality blastocysts. The effects of paternal age were elucidated by adjusting for maternal age.

RESULTS

Among the 571 total blastocysts, 219 euploid blastocysts were analyzed by PGS (38.4%). When the study population was divided into four groups according to both maternal and paternal age, significant differences were only noted between groups that differed by maternal age (group 1 vs. 3, p=0.031; group 2 vs. 4, p=0.027). Further analysis revealed no significant differences in the euploidy rate among the groups according to the morphological grade of the embryos.

CONCLUSION

Paternal age did not have a significant impact on euploidy rates when PGS was performed. An additional study with a larger sample size is needed to clarify the effects of advanced paternal age on IVF outcomes.

Decline in Female Fertility After 40 Years

Important factor related to the conception possibility is women age. The decline in fertility with aging is proven and evident in literature. Infertility is increasing and many couples seek help in advanced techniques such as IVF (in vitro fertilization) in order to overcome the problem caused by aging, but the quality of the oocytes is a significant limiting factor. With the aging the quantity and quality of oocytes decreases, such as the quality of the embryo after fertilization. The accelerated rhythm of life, liberty and women inclusion in all kinds of professions brought many benefits to women, but also increasingly postponing births. Each person is unique individual, and can be more or less fertile compared to the average at same age. Unfortunately, some women has a rapid decline in fertility - accelerate aging, very early, already in the early twenties and when testing them with different methods and exams, the result is very low number of oocytes, low value of anti-Müllerian hormone and also very poor quality of these oocytes, or low ovarian reserve. The problem is that when you have accelerate aging, even IVF techniques can not be of great help in achieving pregnancy. The pregnancy rate (17,65%) and the childbirth rate (5,88%) with the patients older than 40 is very low, although comparable to the data from the scientific literature and speaks in favour of the fact that the success of assisted reproductive techniques is very modest with women older than 44.

Influence of Maternal Aging on Mitochondrial Heterogeneity, Inheritance, and Function in Oocytes and Preimplantation Embryos

Contrasting the equal contribution of nuclear genetic material from maternal and paternal sources to offspring, passage of mitochondria, and thus mitochondrial DNA (mtDNA), is uniparental through the egg. Since mitochondria in eggs are ancestral to all somatic mitochondria of the next generation and to all cells of future generations, oocytes must prepare for the high energetic demands of maturation, fertilization and embryogenesis while simultaneously ensuring that their mitochondrial genomes are inherited in an undamaged state. Although significant effort has been made to understand how the mtDNA bottleneck and purifying selection act coordinately to prevent silent and unchecked spreading of invisible mtDNA mutations through the female germ line across successive generations, it is unknown if and how somatic cells of the immediate next generation are spared from inheritance of detrimental mtDNA molecules. Here, we review unique aspects of mitochondrial activity and segregation in eggs and early embryos, and how these events play into embryonic developmental competency in the face of advancing maternal age.

Paternal age as an independent factor does not affect embryo quality and pregnancy outcomes of testicular sperm extraction-intracytoplasmic sperm injection in azoospermia

This study was performed to evaluate the independent influence of paternal age affecting embryo development and pregnancy using testicular sperm extraction (TESE)-intracytoplasmic sperm injection (ICSI) in obstructive azoospermia (OA) and nonobstructive azoospermia (NOA). Paternal patients were divided into the following groups: ≤30 years, 31-35 years, 36-40 years, 41-45 years and ≥46 years. There were no differences in the rates of fertilisation or embryo quality according to paternal and maternal age. However, clinical pregnancy and implantation rates were significantly lower between those ≥46 years of paternal age compared with other age groups. Fertilisation rate was higher in the OA than the NOA, while embryo quality, pregnancy and delivery results were similar. Clinical pregnancy and implantation rates were significantly lower for patients ≥46 years of paternal age compared with younger age groups. In conclusion, fertilisation using TESE in azoospermia was not affected by the independent influence of paternal age; however, as maternal age increased concomitantly with paternal age, rates of pregnancy and delivery differed between those with paternal age <41 years and ≥46 years. Therefore, paternal age ≥46 years old should be considered when applying TESE-ICSI in cases of azoospermia, and patients should be advised of the associated low pregnancy rates.

The Effect of Paternal Age on Oocyte Donation Outcomes

IMPORTANCE

In recent decades, a trend toward delayed childbearing is noted in developed countries. Whereas the effects of maternal age on fertility, pregnancy complications, and postnatal outcomes have been thoroughly explored, consequences of advanced paternal age are less well known. Oocyte donation cycles can be used as an optimal model to analyze the association between male ageing and reproductive outcomes with minimal confounding.

OBJECTIVE

The purpose of this work was to summarize the updated and relevant literature dealing with the effect of paternal age on oocyte donation outcomes.

RESULTS

According to the available evidence from oocyte donation cycles, it seems that no significant association exists between advanced paternal age and fertility. However, this evidence is based on few studies, many of which are of low quality, yielding conflicting results. In addition, the emerging evidence clearly indicates an increased risk of adverse postnatal manifestations of pregnancies conceived by older fathers, including de novo autosomal dominant disorders, impaired neurocognitive development, and increased risk of malignancy.

CONCLUSIONS AND RELEVANCE

This review may be of aid to medical practitioners in counseling couples on the risks of delayed childbearing.

Effects of maternal age on embryo quality and pregnancy outcomes using testicular sperm with intracytoplasmic sperm injection

Objective

The aim of this study was to evaluate the influence of maternal age on fertilization, embryo quality, and clinical pregnancy in patients undergoing intracytoplasmic sperm injection (ICSI) using testicular sperm from partners with azoospermia.

Methods

A total of 416 ICSI cycles using testicular spermatozoa from partners with obstructive azoospermia (OA, n=301) and non-obstructive azoospermia (NOA, n=115) were analyzed. Female patients were divided into the following age groups: 27 to 31 years, 32 to 36 years, and 37 to 41 years. The rates of fertilization, high-quality embryos, clinical pregnancy, and delivery were compared across maternal age groups between the OA and NOA groups.

Results

The rates of fertilization and high-quality embryos were not significantly different among the maternal age groups. Similarly, the clinical pregnancy and delivery rates were not significantly different. The fertilization rate was significantly higher in the OA group than in the NOA group (p<0.05). Age-group analysis revealed that the fertilization and high-quality embryo rates were significantly different between the OA and NOA groups in patients aged 27 to 31 years old, but not for the other age groups. Although the clinical pregnancy and delivery rates differed between the OA and NOA groups across all age groups, significant differences were not observed.

Conclusion

In couples using testicular sperm from male partners with azoospermia, pregnancy and delivery outcomes were not affected by maternal age. However, women older than 37 years using testicular sperm from partners with azoospermia should be advised of the increased incidence of pregnancy failure.

The Kunming mouse: as a model for age-related decline in female fertility in human

To ascertain whether the Kunming (KM) mouse is an available model for age-related decline in female fertility in human or not, oocytes from young (6–8 weeks), middle-aged (9 months) and aged (12 months) female mice were compared with respect to number of oocytes, frequency of in-vitro maturation (IVM) and in-vitro fertilization (IVF), and meiotic chromosome segregation and alignment. The mean number of pups born per mouse decreased significantly from the young to the middle-aged and the aged mice. The mean number of ovarian follicles, ovarian germinal vesicle oocytes and ovulated MII oocytes decreased significantly with maternal age. The rate of IVM in oocytes from young mice (73.9%) was less significantly than that in oocytes from middle-aged and aged mice (86.1% and 84.4%, respectively). Immunocytochemical analysis showed that ageing caused a significantly higher rate (49.3%) of chromosome misalignment than that (15.7%) of the young mice. The presence of premature chromatids was also significantly higher in MII oocytes of aged mice as compared with young mice (37.8 versus 8.3%). Pronuclear formation was delayed in oocytes of middle-aged and aged females (35.5 and 42.3% respectively in 5 h of IVF) as compared with young mice (88.1%). The study suggests that KM mouse exhibits an age-related decline in female fertility. Significant reduction of germinal vesicle (GV) and MII oocytes and significant increase of metaphase chromosome misalignment and premature chromatid segregation after meiotic maturation of oocytes, similar to human, presumably contribute to the decline in aged KM mice.

Assisted reproductive technologies: a systematic review of safety and effectiveness to inform disinvestment policy

OBJECTIVE

Health policy relating to assisted reproductive technologies (ART) has been variably informed by clinical evidence, social values, political and fiscal considerations. This systematic review examined key factors associated with specific benefits and harms of ART to inform the development of a model for generating policy recommendations within an Australian disinvestment research agenda.

METHODS

Six databases were searched from 1994 to 2009. Included articles contained data on safety and/or effectiveness of in vitro fertilisation (IVF) or IVF with intracytoplasmic sperm injection with reference to female age, male age or cycle rank. Narrative descriptions of key outcomes (live birth, miscarriage) were constructed alongside tabular summaries.

RESULTS

Sixty-eight studies and one registry report were included. There was substantial heterogeneity present within the evidence-base which limited the strength and scope of conclusions that could be drawn. However, this review does affirm the differential effectiveness associated with the ageing of ART patients with regard to live birth and miscarriage.

CONCLUSION

From the available evidence, it was not possible to determine an explicit age or cycle rank that could be used to formulate defensible policy responsive to identified differential effectiveness. Stakeholder interpretation of this evidence-base may assist in developing policy that can incorporate uncertainty and reflect social values.

What should be the maximum FSH dose in IVF/ICSI in poor responders?

Various protocols of ovarian stimulation have been proposed for optimising IVF/ICSI results in women presenting with a poor response to controlled ovarian stimulation; however, achieving a good response to stimulation for this category of patients still remains a challenge. The most extensively employed strategy to improve follicular response in these so-called 'poor responders' involves the use of high doses of gonadotrophins. A small number of randomised controlled trials and retrospective studies have evaluated the effectiveness of the high-dose FSH regimes over a 300 IU threshold. The results of these studies have shown these approaches to be of little or no clinical benefit, although both the costs of treatment and side-effects were higher. There are other studies that have examined 450 IU FSH regimens or even more. This paper presents an overview in all these clinical trials, trying to evaluate the safest and most effective upper limit of FSH that may be used for controlled ovarian hyperstimulation.

Outcome of 1114 ICSI and embryo transfer cycles of women 40 years of age and over

The purpose of this study was to contribute to the development of strategies to obtain acceptable outcomes in assisted reproduction treatments in women over 40 years of age. A retrospective study was carried out on the database of the German Hospital in Istanbul using data from the years 1997 to 2004. A total of 1114 embryo transfer cycles were assessed. The pregnancy, implantation and delivery rates of the assessed population were 18.2, 8.3 and 10.9% respectively. The results showed that the demographics and outcome of cycles of women at 40 years differed significantly from those over 40. Cycles in which six or more oocytes were retrieved displayed better characteristics and outcome than those with five or fewer. The clinical pregnancy and delivery rates after transfer of three embryos were similar to four or more. Therefore, women over 40 years with a good ovarian response and at least three embryos available for transfer have an acceptable pregnancy and delivery rate with a low multiple pregnancy risk.

The effect of advancing paternal age on pregnancy and live birth rates in couples undergoing in vitro fertilization or gamete intrafallopian transfer

OBJECTIVE

This study was undertaken to determine effects of male aging on sperm parameters, fertilization, pregnancy, and live birth rates among in vitro fertilization (IVF) or gamete intrafallopian transfer (GIFT) couples. The impact of female age was also investigated.

STUDY DESIGN

Prospective study was made up of 221 IVF and GIFT couples.

RESULTS

Pregnancy rates declined as the male subjects aged. Each additional year of paternal age was associated with 11% increased odds (P=.007) of not achieving a pregnancy, and 12% odds (P=.01) of not having a successful live birth. For first-time IVF/GIFT recipients, each additional year of paternal age was associated with a 5% increased odds of not achieving a pregnancy, whereas for repeaters it was 40% (P=.01). Advancing maternal age was associated with decreased numbers of oocytes retrieved or fertilized. Women 40 years or older compared with younger than 35 years had greater than 4-fold risk of not becoming pregnant, and greater than 20-fold risk of not achieving a live birth.

CONCLUSION

Advancing paternal (and maternal) age had a deleterious effect on IVF and GIFT outcomes.

Effect of male age on fertility: evidence for the decline in male fertility with increasing age

OBJECTIVE

To evaluate the effect of men's age on time to pregnancy (TTP) using age at the onset of pregnancy attempts, adjusting for the confounding effects of women's age, coital frequency, and life-style characteristics.

DESIGN

Observational study.

SETTINGS

Teaching hospital in Hull, United Kingdom.

PATIENT(S)

Two thousand one hundred twelve consecutive pregnant women.

INTERVENTION(S)

A questionnaire inquiring about TTP, contraceptive use, pregnancy planning, previous subfertility, previous pregnancies, age, and individual life-style characteristics of both partners.

MAIN OUTCOME MEASURE(S)

Time to pregnancy, conception rates, and relative risk of subfecundity for men and women's age groups.

RESULTS

As with women's age, increasing men's age was associated with significantly rising TTP and declining conception rates. A fivefold increase in TTP occurred with men's age >45 years. Relative to men <25 years old, those >45 years were 4.6-fold and 12.5-fold more likely to have had TTP of >1 or >2 years. Restricting the analysis to partners of young women revealed similar effects of increasing men's age. Women >35 years were 2.2-fold more likely to be subfertile than women <25 years. The results were comparable, whether age at conception or at the onset of pregnancy attempts was analyzed, and they remained unchanged after adjustment for the confounding factors.

CONCLUSION(S)

Evidence for and quantification of the decline in men's fertility with increasing age is provided.

Performance of basal follicle-stimulating hormone in the prediction of poor ovarian response and failure to become pregnant after in vitro fertilization: a meta-analysis

OBJECTIVE

To assess the predictive performance and clinical value of basal FSH as a test for ovarian reserve in in vitro fertilization (IVF) patients.

DESIGN

Meta-analysis.

SETTING

Tertiary fertility center.

PATIENT(S)

Patients undergoing IVF.

INTERVENTION(S)

None.

MAIN OUTCOME MEASURE(S)

Poor ovarian response, nonpregnancy.

RESULT(S)

We located 21 studies that had reported on basal FSH and IVF outcome. No single study met high standards of methodological rigor; most studies are of moderate methodological quality only. The summary receiver operating characteristic curve indicated a moderate predictive performance for poor response, and a low predictive performance for nonpregnancy. Predictions with a substantial shift from pre-FSH-test probability to post-FSH test probability are only achieved at extreme cut-off levels for basal FSH. Sensitivity of such cut-off levels, for both the prediction of poor response and nonpregnancy, is limited.

CONCLUSION(S)

Clinical value of testing for basal FSH is restricted to a small minority of patients. Basal FSH should not be regarded as a useful routine test for the prediction of IVF outcome. The development of better tests to assess ovarian reserve remains of importance.

Analysis of donor heterogeneity as a factor affecting the clinical outcome of oocyte donation

This study investigated factors that may affect the clinical outcome of oocyte donation on the basis of data from a clinical programme involving 243 treatment cycles analysed retrospectively. In each cohort, oocytes were distributed randomly to one, two or three recipients, which enabled the outcomes in terms of pregnancy and live birth rates to be compared among donors. The results were compared with respect to age of the donor and recipient, number of oocytes collected, fertilization and cleavage rates, qualitative embryo criteria (morphological grade) and other clinical criteria. Most variables had no significant effect on either outcome, although the live birth rate varied inversely with recipient age. Unsurprisingly, the pregnancy rate was correlated positively with the number of embryos transferred. Most of the variation in pregnancy and live birth rates (85-90%) could not be accounted for by any specific donation characteristic, indicating that interdonor heterogeneity was the result of idiopathic factors. The factor most predictive of a recipient's cycle outcome was a history of previous success of the donor, which accounted for approximately 30% of the variation in live birth rates. Pregnancy success rates varied widely among oocyte donors, as has been found among sperm donors. This observation highlights the need to identify markers that predict developmental competence and help to identify the genetic and environmental bases of differential fertility. In conclusion, the quality of oocytes varied widely among women presumed to be fertile by clinical criteria, and the causative factors set a major limitation on the prospects of improving the outcome of egg donation.