Culture conditions in the IVF laboratory: state of the ART and possible new directions

In the last four decades, the assisted reproductive technology (ART) field has witnessed advances, resulting in improving pregnancy rates and diminishing complications, in particular reduced incidence of multiple births. These improvements are secondary to advanced knowledge on embryonic physiology and metabolism, resulting in the ability to design new and improved culture conditions. Indeed, the incubator represents only a surrogate of the oviduct and uterus, and the culture conditions are only imitating the physiological environment of the female reproductive tract. In vivo, the embryo travels through a dynamic and changing environment from the oviduct to the uterus, while in vitro, the embryo is cultured in a static fashion. Importantly, while culture media play a critical role in optimising embryo development, a large host of additional factors are equally important. Additional potential variables, including but not limited to pH, temperature, osmolality, gas concentrations and light exposure need to be carefully controlled to prevent stress and permit optimal implantation potential. This manuscript will provide an overview of how different current culture conditions may affect oocyte and embryo viability with particular focus on human literature.

Neurodevelopmental Outcomes of Pregnancies Resulting from Assisted Reproduction: A Review of the Literature

The term infertility is defined as the lack of conception within 1 year of unprotected intercourse. It affects more than 80 million individuals worldwide. It is estimated that 10-15% of couples of reproductive age are challenged by reproductive issues. Assisted reproduction techniques (ART) are responsible for more than 4% of live births. Our aim is to review the research on neurodevelopmental outcomes of newborns born after the implementation of assisted reproduction methods compared to those conceived naturally. We conducted a comprehensive search of the PubMed, Crossref and Google Scholar electronic databases for related articles up to June 2022 using the PRISMA guidelines. Our research revealed a large number of long term follow-up studies between 2 and 18 years of age, with comparable developmental outcomes. Many studies compared the effects of different infertility treatments against natural conception. The review of the literature revealed that ART is safe, as the majority of studies showed no effect on the neurodevelopmental outcomes of the offspring. In most cases when such an effect was observed, it could be attributed to confounding factors such as subfertility, multiple pregnancies and gestational age at delivery. Finally, the increase in the prevalence of neurodevelopmental disorders after ART, as described in studies with statistically significant results, is predominantly marginal, and given the low incidence of neurodevelopmental disorders in the general population, its clinical significance is debatable.

Long-term neurodevelopmental outcome in children after antenatal intravenous immune globulin treatment in fetal and neonatal alloimmune thrombocytopenia

BACKGROUND

Children with fetal and neonatal alloimmune thrombocytopenia (FNAIT) face increased risk of intracranial hemorrhage (ICH) potentially leading to developmental impairment. To prevent ICH, pregnant women with alloantibodies against fetal platelets are often treated with intravenous immunoglobulin (IVIg). IVIg appears effective in vastly reducing the risk of fetal or neonatal bleeding complications. However, information on long-term neurodevelopment of these children is lacking.

OBJECTIVE

To evaluate long-term neurodevelopmental outcome in children with FNAIT who were treated with IVIg antenatally.

STUDY DESIGN

An observational cohort study was performed including children of mothers who were treated with IVIg during pregnancy because a previous child was diagnosed with FNAIT. Children, were invited for a follow-up assessment including standardized cognitive and neurologic tests. The parents were asked to complete a behavioral questionnaire and school performance reports. The primary outcome was severe neurodevelopmental impairment (NDI), defined as severe cognitive impairment (IQ < 70), cerebral palsy with Gross Motor Function Classification System (GMFCS) Level ≥ 3, bilateral blindness, and/or bilateral deafness (requiring amplification). The secondary outcome was mild to moderate NDI, defined as either mild to moderate cognitive impairment (IQ < 85), cerebral palsy with GMFCS Level ≤ 2, minor neurologic dysfunction, vision loss, and/or hearing loss.

RESULTS

Between 2003 and 2017, 51 children were liveborn after antenatal IVIg treatment. One family moved abroad and was therefore not eligible for inclusion. In total, 82% (41/50) of the eligible cases were included for neurodevelopmental assessment at a median age of 9 years and 8 months. Severe NDI was not detected. The incidence of mild to moderate NDI was 14% (6/41, 95% confidence interval: 6%-29%). The children's mean cognitive score, behavioral scores, and academic achievement were not different from the Dutch norm groups. Neuroimaging was performed in 90% (37/41) of cases. Severe ICH had been diagnosed in two cases (5%), one antenatally before the start of IVIg and the other case 1 day after birth. Both cases had a normal neurodevelopmental outcome.

CONCLUSION

The risk of NDI in children whose mothers were treated for FNAIT with antenatal IVIg is comparable to that in the general population.

Effect of medically assisted reproduction (MAR) and pregnancy planning on Bayley-III Screening Test subscales in preterm infants at 12 months of corrected age: a cross-sectional study

Background

The association between medically assisted reproduction and pregnancy planning on overall developmental outcomes of infants has been studied in relatively few studies. The availability of accurate tools for the early detection of developmental delays is a major issue. The purpose of this study is describing the average neurodevelopment of preterm infants and assessing the association between medically assisted reproduction, pregnancy planning and neurodevelopmental outcomes among Hungarian preterm infants.

Methods

Cross-sectional study of preterm infants with gestational age < 37 weeks (N = 171) who underwent developmental assessment using Bayley-III Screening Test (Bayley Scales of Infant and Toddler Development Screening Test – Third Edition) in five developmental domains (cognitive, receptive and expressive language, fine and gross motor) at 12 months of corrected age. We examined the developmental pattern of infants and the potential associations between medically assisted reproduction, pregnancy planning and Bayley-III Screening Test subscales. Information on the mode of conception and pregnancy planning was obtained through parental anamnesis.

Results

Concerning the risk for developmental delay, the language and motor subscales were the most affected. Examination of the mode of conception and developmental outcomes revealed higher neurodevelopmental skills in infants who were conceived through medically assisted reproduction. Significantly lower cognitive, receptive and expressive language skills were found to be associated with unplanned pregnancies. Multi-way analysis of variance was conducted in order to assess the impact of the mode of conception and pregnancy planning on subscales.

Conclusions

We cannot unambiguously conclude that MAR and pregnancy planning had a solely positive effect on the development of preterm infants at 12 months of corrected age, but our results are vital for the design and implementation of further research.

IVF procedures are not, but subfertility is associated with neurological condition of 9-year-old offspring

In vitro fertilization (IVF) is not associated with neurological abnormalities in offspring's early childhood. Yet, it is unclear whether this is also true for school age. Neither do we know the role of parental subfertility in offspring's neurological development. The present study examined neurological condition at 9 years of 57 singletons born after controlled ovarian hyperstimulation IVF (COH-IVF), 46 singletons born after modified natural cycle IVF (MNC-IVF) and 66 singletons born to subfertile parents after natural conception (Sub-NC). To assess the effect of subfertility, the groups were pooled to form a subfertile group, and compared with a prospectively followed fertile reference group (n = 282). The sensitive Minor Neurological Dysfunction (MND) examination was used, resulting in the detailed Neurological Optimality Score (NOS) and the prevalence of the clinically relevant complex MND. Neurological condition of the three subfertile groups did not differ significantly: median NOS was 53 in each subfertile group and the prevalence of complex MND in the three subfertile groups was 30%, 37% and 36%, respectively. However, the NOS was lower and the prevalence of complex MND higher in children born to subfertile couples than in children of fertile couples (adjusted mean difference [95% CI]: -4.48 [-5.53 to -3.42]) and adjusted OR [95% CI]: 5.13 [2.60-10.16], respectively). We conclude that ovarian hyperstimulation, in vitro procedures, and the combination of both were not associated with a less favourable neurological outcome of 9-year-old singletons. However, the presence of parental subfertility was associated with less favourable neurological outcome of offspring at 9 years follow up.

Neurological condition assessed with the Hempel examination and cognition and behaviour at 4years

AIM

To investigate associations between neurological condition, assessed with the Hempel examination, in terms of minor neurological dysfunction (MND) and neurological optimality, and cognition and behaviour at 4years.

STUDY DESIGN

Cross-sectional analyses within a prospective, assessor-blinded follow-up study.

SUBJECTS

Four-year-old singletons born to subfertile parents (n=235; 120 boys).

OUTCOME MEASURES

Outcome parameters were complex minor neurological dysfunction (complex MND) and the neurological optimality score (NOS). Cognitive outcome was evaluated with the Kaufman Assessment Battery for Children, resulting in a total intelligence quotient (IQ). Behavioural outcome was evaluated with the Child Behavior Checklist, resulting in a total problem T-score.

RESULTS

Fifty-seven (24.3%) children had complex MND. None of the children showed fine motor dysfunction, suggesting a ceiling effect of the Hempel assessment. Complex MND was not correlated with IQ or total problem T-score. Nevertheless, a higher NOS was correlated with a higher IQ and a lower total problem T-score (adjusted mean estimate [95% confidence interval]: cognition: 0.445 [0.026; 0.865], p=0.038; behaviour: -0.458 [-0.830; -0.087], p=0.016).

INTERPRETATION

At age 4, complex MND assessed with the Hempel assessment was not associated with cognition and behaviour, presumably due to a ceiling effect in the Hempel domain of fine motor function. A more optimal neurological condition was associated with higher IQ and better behaviour.

Predictive value of general movements' quality in low-risk infants for minor neurological dysfunction and behavioural problems at preschool age

BACKGROUND

General movement (GM) assessment is a well-established tool to predict cerebral palsy in high-risk infants. Little is known on the predictive value of GM assessment in low-risk populations.

AIMS

To assess the predictive value of GM quality in early infancy for the development of the clinically relevant form of minor neurological dysfunction (complex MND) and behavioral problems at preschool age.

STUDY DESIGN

Prospective cohort study.

SUBJECTS

A total of 216 members of the prospective Groningen Assisted Reproductive Techniques (ART) cohort study were included in this study. ART did not affect neurodevelopmental outcome of these relatively low-risk infants born to subfertile parents.

OUTCOME MEASURES

GM quality was determined at 2 weeks and 3 months. At 18 months and 4 years, the Hempel neurological examination was used to assess MND. At 4 years, parents completed the Child Behavior Checklist; this resulted in the total problem score (TPS), internalizing problem score (IPS), and externalizing problem score (EPS). Predictive values of definitely (DA) and mildly (MA) abnormal GMs were calculated.

RESULTS

DA GMs at 2 weeks were associated with complex MND at 18 months and atypical TPS and IPS at 4 years (all p<0.05). Sensitivity and positive predictive value of DA GMs at 2 weeks were rather low (13%-60%); specificity and negative predictive value were excellent (92%-99%). DA GMs at 3 months occurred too infrequently to calculate prediction. MA GMs were not associated with outcome.

CONCLUSIONS

GM quality as a single predictor for complex MND and behavioral problems at preschool age has limited clinical value in children at low risk for developmental disorders.

Effects of in vitro fertilization and maternal characteristics on perinatal outcomes: a population-based study using siblings

OBJECTIVE

To study birthweight in consecutively born sibling singletons conceived with and without in vitro fertilization (IVF) to disentangle the effects of maternal characteristics from those of the IVF treatment itself.

DESIGN

Population-based study.

SETTING

Not applicable.

PATIENT(S)

Firstborn and secondborn children from a 9-year birth cohort (1999-2007) comprising of 272,551 women who conceived two siblings.

INTERVENTION(S)

No intervention; children were conceived naturally or through IVF.

MAIN OUTCOME MEASURE(S)

Birthweight.

RESULT(S)

The study included 545,102 children born by natural conception (NC) or IVF with the data set obtained from the population-based Netherlands Perinatal Registry (PRN) containing information on pregnancies, deliveries, and neonatal outcomes. We used two approaches: [1] the intersibling approach and [2] the sibling-ship approach. In the first approach we included children born to four groups of mothers who conceived in the following order (numbers indicate birth order): NC1-NC2 (reference, n = 254,721), IVF1-NC2 (n = 1342), NC1-IVF2 (n = 471), and IVF1-IVF2 (n = 687). Several comparisons were made to interpret the effects of IVF and maternal characteristics separately. In the second approach, perinatal outcomes of IVF children (n = 1,813) were compared with those of their NC siblings (n = 1,813). The intersibling analyses suggested an association between maternal characteristics and a lower birthweight, with estimates of the maternal effect ranging from -7 g (95% CI, -40; 26) to -101 g (95% CI, -170; -32). Neither the intersibling analyses nor the sibling-ship analyses indicated an additional adverse effect of IVF treatment itself.

CONCLUSION(S)

Maternal characteristics of subfertile women are associated with a lower birthweight. In vitro fertilization treatment itself does not additionally contribute to a lower birthweight in the offspring.

Dysmorphic features and developmental outcome of 2-year-old children

AIM

The aim of this study was to assess the associations between dysmorphic features and neurological, mental, psychomotor, and behavioural development in order to improve our understanding of aetiological pathways leading to minor developmental problems.

METHOD

In our cross-sectional study, 272 generally healthy 2-year-olds (143 males, 129 females; median gestational age 39 weeks, [range 30-43wks]), born after a parental history of subfertility either with or without fertility treatment, were examined. Dysmorphic features were classified as abnormalities (clinically relevant or not), minor anomalies, or common variants according to Merks' classification system. Hempel's neurological assessment resulted in a neurological optimality score (NOS) and fluency score. Mental and psychomotor development were assessed with the Dutch version of the Bayley Scales of Infant Development and behavioural development with the Achenbach Child Behaviour Checklist.

RESULTS

Of the different types of dysmorphic feature, clinically relevant abnormalities were most strongly associated with a lower NOS (difference -2.53, 95% confidence interval [CI] -4.23 to -0.83) and fluency score (difference -0.62, 95% CI -1.1 to -0.15). The presence of one or more abnormalities (clinically relevant or not) or one or more common variants was significantly associated with a lower NOS, and the presence of three or more minor anomalies was associated with lower fluency scores. Dysmorphic features were not associated with mental, psychomotor, or behavioural development.

INTERPRETATION

As dysmorphic features originate during the first trimester of pregnancy, the association between dysmorphic features and minor alterations in neurodevelopment may suggest an early ontogenetic origin of subtle neurological deviations.

IVF culture media: past, present and future

BACKGROUND

The advances in the world of IVF during the last decades have been rapid and impressive and culture media play a major role in this success. Until the 1980s fertility centers made their media in house. Nowadays, there are numerous commercially available culture media that contain various components including nutrients, vitamins and growth factors. This review goes through the past, present and future of IVF culture media and explores their composition and quality assessment.

METHODS

A computerized search was performed in PubMed regarding IVF culture media including results from 1929 until March 2014. Information was gathered from the websites of companies who market culture media, advertising material, instructions for use and certificates of analysis. The regulation regarding IVF media mainly in the European Union (EU) but also in non-European countries was explored.

RESULTS

The keyword 'IVF culture media' gave 923 results in PubMed and 'embryo culture media' 12 068 results dating from 1912 until March 2014, depicting the increased scientific activity in this field. The commercialization of IVF culture media has increased the standards bringing a great variety of options into clinical practice. However, it has led to reduced transparency and comparisons of brand names that do not facilitate the scientific dialogue. Furthermore, there is some evidence suggesting that suboptimal culture conditions could cause long-term reprogramming in the embryo as the periconception period is particularly susceptible to epigenetic alterations. IVF media are now classified as class III medical devices and only CE (Conformité Européene)-marked media should be used in the EU.

CONCLUSION

The CE marking of IVF culture media is a significant development in the field. However, the quality and efficiency of culture media should be monitored closely. Well-designed randomized controlled trials, large epidemiological studies and full transparency should be the next steps. Reliable, standardized models assessing multiple end-points and post-implantation development should replace the mouse embryo assay. Structured long-term follow-up of children conceived by assisted reproduction technologies and traceability are of paramount importance.

Increased time to pregnancy is associated with suboptimal neurological condition of 2-year-olds

OBJECTIVE

To evaluate whether time to pregnancy (TTP) is associated with neurological condition of 2-year-old children born to subfertile parents.

DESIGN

Data collected in a prospective, assessor-blinded follow-up study were used for cross-sectional analyses.

PATIENTS

Participants were the singletons of the Groningen assisted reproductive technique cohort study: all children were born to subfertile couples (n=209). The active waiting TTP of the couples obtained from fertility charts was recorded in years and months, and was converted to decimal years.

MAIN OUTCOME MEASURE

The presence of minor neurological dysfunction (MND), assessed with the Hempel examination.

RESULTS

MND was present in 16 (7.7%) children. TTP of children with MND (median 4.1, range 1.6-13.2) was significantly longer than that of children without MND (median 2.8, range 0.1-13.3; Mann-Whitney U test p=0.014). Logistic regression analysis on the contribution of TTP to MND resulted in a crude OR of 1.27 (95% CI 1.06 to 1.54). After correction for gestational age, parental age and parental level of education, the association remained statistically significant: OR=1.30 (95% CI 1.05 to 1.61).

CONCLUSIONS

Increased TTP was associated with suboptimal neurological development in 2-year-old children. This suggests that subfertility and its determinants are involved in the genesis of neurodevelopmental problems.

Movement variation in infants born following IVF/ICSI with and without ovarian hyperstimulation

BACKGROUND

The effect of in vitro fertilisation (IVF) on neurodevelopment is not fully understood. Probably, IVF does not affect traditional measures of neurodevelopment in infancy. Recently, an instrument, the Infant Motor Profile (IMP), was developed that evaluates the quality of motor behaviour. It includes the evaluation of movement variation (i.e. movement repertoire size), a parameter reflecting the integrity of cortical connectivity.

AIM

To evaluate the effect of ovarian hyperstimulation and the in vitro procedure on movement variation during infancy.

STUDY DESIGN

Prospective cohort study.

SUBJECTS

Singletons born following IVF or intracytoplasmic sperm injection (ICSI) with conventional controlled ovarian hyperstimulation (COH-IVF/ICSI, n=68), in a modified natural cycle (MNC-IVF/ICSI, n=57) and natural conception born to subfertile couples (Sub-NC, n=90).

OUTCOME MEASURES

Children were assessed with the IMP at 4, 10 and 18 months, resulting in a total IMP score and five domain scores: variation, variability, symmetry, fluency and performance. Primary outcome was the domain score variation.

RESULTS

A significant effect of study group was observed for the variation score up until 18 months of age (p=0.039). COH-IVF/ICSI children had a significantly lower mean variation score than MNC-IVF/ICSI children (mean difference [95% confidence interval] -1.010 [-1.766; -0.254]). Mean variation scores of COH-IVF/ICSI and Sub-NC children were similar; the same held true for the comparison between MNC-IVF/ICSI and Sub-NC. Total IMP scores and other domain scores of the three groups were similar.

CONCLUSION

The present study did not demonstrate a clear effect of ovarian hyperstimulation and the in vitro procedure on movement variation throughout infancy.

Assisted reproduction and child neurodevelopmental outcomes: a systematic review

OBJECTIVE

To systematically review the existing literature on neurodevelopmental outcomes in children born after medically assisted reproduction compared with those of children born after spontaneous conception.

DESIGN

Systematic review.

SETTING

Not applicable.

PATIENT(S)

Children born after medically assisted reproduction vs. reference groups of spontaneously conceived children.

INTERVENTION(S)

Data were reviewed from worldwide published articles, without restrictions as to publication year or language. A total of 80 studies included between 31 and 2,446,044 children.

MAIN OUTCOME MEASURE(S)

Child neurodevelopmental outcomes categorized as cognitive, behavioral, emotional or psychomotor development, or diagnoses of mental disorders.

RESULT(S)

For infants, studies on psychomotor development showed no deficits, but few investigated cognitive or behavioral development. Studies on toddlers generally reported normal cognitive, behavioral, socio-emotional, and psychomotor development. For children in middle childhood, development seems comparable in children born after assisted reproduction and controls, although fewer studies have been conducted with follow-up to this age. Very few studies have assessed neurodevelopmental outcomes among teens, and the results are inconclusive. Studies investigating the risk of diagnoses of mental disorders are generally large, with long follow-up, but the results are inconsistent.

CONCLUSION(S)

It may tentatively be concluded that the neurodevelopment of children born after fertility treatment is overall comparable to that in children born after spontaneous conception.