Is IVF/ICSI [corrected] an Independent Risk Factor for Spontaneous Preterm Birth in Singletons? A Population-Based Cohort Study

A Framework for Neonatal Prematurity Information System Development Based on a Systematic Review on Current Registries: An Original Research

Background

Registries are regarded as a just valuable fount of data on determining neonates suffering prematurity or low birth weight (LBW), ameliorating provided care, and developing studies.

Objective

This study aimed to probe the studies, including premature infants' registries, adapt the needed minimum data set, and provide an offered framework for premature infants' registries.

Material and Methods

For this descriptive study, electronic databases including PubMed, Scopus, Web of Science, ProQuest, and Embase/Medline were searched. In addition, a review of gray literature was undertaken to identify relevant studies in English on current registries and databases. Screening of titles, abstracts, and full texts was conducted independently based on PRISMA guidelines. The basic registry information, scope, registry type, data source, the purpose of the registry, and important variables were extracted and analyzed.

Results

Fifty-six papers were qualified and contained in the process that presented 51 systems and databases linked in prematurity at the popular and government levels in 34 countries from 1963 to 2017. As a central model of the information management system and knowledge management, a prematurity registry framework was offered based on data, information, and knowledge structure.

Conclusion

To the best of our knowledge, this is a comprehensive study that has systematically reviewed prematurity-related registries. Since there are international standards to develop new registries, the proposed framework in this article can be beneficial too. This framework is essential not only to facilitate the prematurity registry design but also to help the collection of high-value clinical data necessary for the acquisition of better clinical knowledge.

A systematic review of prediction models for spontaneous preterm birth in singleton asymptomatic pregnant women with risk factors

Backgrounds

Spontaneous preterm birth (SPB) is a global problem. Early screening, identification, and prevention in asymptomatic pregnant women with risk factors for preterm birth can help reduce the incidence and mortality of preterm births. Therefore, this study systematically reviewed prediction models for spontaneous preterm birth, summarised the model characteristics, and appraised their quality to identify the best-performing prediction model for clinical decision-making.

Methods

PubMed, Embase, Cochrane Library, China National Knowledge Infrastructure, China Biology Medicine disc, VIP Database, and Wanfang Data were searched up to September 27, 2021. Prediction models for spontaneous preterm births in singleton asymptomatic pregnant women with risk factors were eligible for inclusion. Six independent reviewers selected the eligible studies and extracted data from the prediction models. The findings were summarised using descriptive statistics and visual plots.

Results

Twelve studies with twelve developmental models were included. Discriminative performance was reported in 11 studies, with an Area Under the Curve (AUC) ranging from 0.75 to 0.95. The AUCs of the seven models were greater than 0.85. Cervical length (CL) is the most commonly used predictor of spontaneous preterm birth. A total of 91.7% of the studies had a high risk of bias in the analysis domain, mainly because of the small sample size and lack of adjustment for overfitting.

Conclusion

The accuracy of the models for spontaneous preterm births in singleton asymptomatic women with risk factors was good. However, these models are not widely used in clinical practice because they lack replicability and transparency. Future studies should transparently report methodological details and consider more meaningful predictors with new progress in research on preterm birth.

Risk factors associated with preterm birth in singletons born after IVF: a national cohort study

RESEARCH QUESTION

What are the risk factors for prematurity other than intrauterine growth restriction in singletons after IVF?

DESIGN

Data were collected from a national registry, based on an observational prospective cohort of 30,737 live births after assisted reproductive technology (fresh embryo transfers: n = 20,932 and frozen embryo transfer [FET] n = 9805) between 2014 and 2015. A population of not-small for gestational age singletons conceived after fresh embryo transfers and FET, and their parents, was selected. Data on a number of variables were collected, including type of infertility, number of oocytes retrieved and vanishing twins.

RESULTS

Preterm birth occurred in 7.7% (n = 1607) of fresh embryo transfers and 6.2% (n = 611) of frozen-thawed embryo transfers (P < 0.0001; adjusted odds ratio [aOR] = 1.34 [1.21-1.49]). Endometriosis and vanishing twin increased the risk of preterm birth after fresh embryo transfer (P < 0.001; aOR 1.32 and 1.78, respectively). Polycystic ovaries or more than 20 oocytes retrieved also increased preterm birth risk (aOR 1.31 and 1.30; P = 0.003 and P = 0.02, respectively); large oocyte cohort (>20) was no longer associated with the risk of prematurity in FET.

CONCLUSION

Endometriosis remains a risk for prematurity even in the absence of intrauterine growth retardation, which suggests a dysimmune effect. Large oocyte cohorts obtained by stimulation, without clinical polycystic ovary syndrome diagnosed before attempts, do not affect FET outcomes, reinforcing the idea of a phenotypic difference in the clinical presentation of polycystic ovary syndrome.

Association of MTHFR 677C>T polymorphism with pregnancy outcomes in IVF/ICSI-ET recipients with adequate synthetic folic acid supplementation

Methylenetetrahydrofolate reductase (MTHFR) genetic polymorphism rs1801133 (677C>T) will decrease the utilization of folate. Folate deficiency and its resulting homocysteine (HCY) accumulation can impair female fertility. Folic acid (FA) supplementation is necessary in pregnant women who are undergoing in-vitro fertilization (IVF)/intracytoplasmic sperm injection (ICSI) - embryo transfer (ET), and especially in women with MTHFR rs1801133 C-to-T mutations. At present, affordable and accessible synthetic FA is mainly used. However, some studies have suggested that 5-methylenetetrahydrofolate (5-MTHF), a type of active FA, may be more suitable for women with the MTHFR 677C>T polymorphism, since it is safer and more effective. This retrospective study aimed to evaluate whether the MTHFR rs1801133 gene polymorphism is related to the pregnancy outcomes of IVF/ICSI-ET recipients after sufficient supplementation with FA instead of 5-MTHF. Data on 692 women undergoing IVF/ICSI-ET and taking adequate FA were collected. Participant characteristics were compared using the Kruskal-Wallis test and Pearson chi-square test. Logistic regressions were used to calculate the odds ratio (OR) and 95% confidence interval (95% CI), after adjusting for age, BMI, method of fertilization, method of embryo transfer and number of embryos transferred. An additive model (T/T vs. C/C), dominant model (C/T + T/T vs. C/C), and recessive model (T/T vs. C/T + C/C) were evaluated. Analysis revealed that MTHFR rs1801133 in IVF/ICSI-ET women with adequate FA supplementation was not associated with the pregnancy rate but with age (OR = 0.91, 95% CI = 0.88, 0.94, P < 0.001) and BMI (OR = 0.95, 95% CI = 0.90, 0.997, P = 0.037). In 349 clinically pregnant women, no association of the MTHFR 677C>T with pregnancy outcomes was found in the additive model, dominant model, or recessive model. Of the 273 women with positive pregnancy outcomes, 34 had a preterm delivery. MTHFR 677C>T was not associated with a preterm delivery after adjusting for age and BMI. The current results indicated that MTHFR polymorphism rs1801133 was not related to the pregnancy rate or pregnancy outcomes of women undergoing IVF/ICSI-ET with adequate synthetic FA supplementation, suggesting that simple supplementation with less expensive and readily available FA, rather than expensive 5-MTHF, appeared to be appropriate.

Maternal advanced age, single parenthood, and ART increase the risk of child morbidity up to five years of age

Background

Advanced maternal age, single status and use of assisted reproductive technology (ART) are increasing in mothers in high-income countries, and all are known risk factors for negative obstetric outcomes. Less is known about their long-term consequences for childhood morbidity. Thus, the aim of this study was to investigate morbidity up to five years of age, in the children of older, single, and/or ART-treated mothers.

Methods

A cross-sectional using Swedish registers was performed comprising 23 772 children. The prevalence of diagnosis and the number of hospital visits for specialist care, were compared and analyzed in relation to maternal age at childbirth, maternal civil status, and mode of conception. The odds ratio for specialized care within each ICD-chapter were estimated using single and multiple logistic regression.

Results

Children born to single mothers and children conceived using ART had significantly more outpatient visits for specialist care and significantly more diagnoses compared to children with married/cohabiting mothers, and spontaneously conceived children. Children born to mothers of advanced maternal age (≥40) had fewer in- and outpatient visits. However, they were significantly more often diagnosed within ICD-chapters XVI, XVII i.e., they experienced more morbidity in the neonatal period.

Conclusion

The results indicate that children born to single mothers and children of ART-treated mothers have a higher morbidity and consume more specialist care than children of married/cohabiting and spontaneously pregnant mothers. We conclude that the use of ART, maternal single status and advanced maternal age are risk factors of importance to consider in pediatric care and when counseling women who are considering ART treatment.

FIGO good practice recommendations on reduction of preterm birth in pregnancies conceived by assisted reproductive technologies

FIGO (the International Federation of Gynecology and Obstetrics) supports assisted reproductive technologies (ART) to achieve pregnancy and supports their availability in all nations. However, the increased frequency of preterm birth must be taken into account. Therefore, before in vitro fertilization (IVF) is started, other approaches, including expectant management, should be considered. Single embryo transfer is the best approach to ensure a live, healthy child. However, increased risks for preterm birth are also associated with a singleton IVF pregnancy and should be discussed and contrasted with spontaneous conception. Increased preterm birth and other adverse pregnancy outcomes in singleton IVF cycles warrant investigations to elucidate and mitigate. Minimizing embryo manipulation during cell culture is recommended. Increased risk of preterm birth and other pregnancy complications in ART could reflect the underlying reasons for infertility. This information should be discussed and further explored.

Outcomes of Very Preterm Infants Conceived with Assisted Reproductive Technologies

OBJECTIVE

To compare mortality and early respiratory outcomes of very preterm infants conceived via assisted reproductive technology (ART) vs spontaneously.

STUDY DESIGN

We identified inborn infants (July 2014-July 2019) with gestational age <32 weeks (n = 439); 54 cases were ART conceived. Spontaneously conceived controls (n = 103) were matched by multiple gestation status and gestational age. Primary outcome was 1-year mortality. Secondary outcomes were receipt of respiratory support and supplemental oxygen at 7 and 28 days and 36 weeks of postmenstrual age. We evaluated the association between conception method and outcomes by logistic regression, with adjustment for sociodemographic status.

RESULTS

Women who conceived via ART had increased rates of prepregnancy and gestational diabetes, and no differences in rates of hypertensive disorders. Infant 1-year mortality was not different by mode of conception (ART 11.8% vs spontaneous 7.1%, P = .49). Infants conceived by ART were less likely to receive respiratory support or supplemental oxygen at all time points, but this relationship only reached significance for receipt of oxygen at 28 days (ART 20.8% vs spontaneous 39.0%, P = .03); this remained true after adjustment for race/ethnicity and socioeconomic index.

CONCLUSIONS

When controlling for gestational age and multiple gestation status, very preterm infants conceived following ART had similar outcomes as those conceived spontaneously.

The Kind of Conception Affects the Kind of Cesarean Delivery in Primiparous Women

BACKGROUND

So far, multiple factors have been found to be related to the IVF procedure, the most prevalent being extremes of maternal age, infections, previous gynecological history, infertility and others. Although women achieve the coveted pregnancy with the development of IVF technology, the rapid increase contributes to the increase of primary cesarean sections rates.

OBJECTIVE

The aim of the study was to identify if the kind of conception affects the kind of cesarean delivery among primiparous women in Greece.

METHODS

This cross-sectional observational study took place from September 2019 to February 2020 at the University Hospital of Larisa in Greece. One hundred and sixty-two primiparous women who underwent a cesarean section (c-section) after IVF (n=27) and natural conception (n=135) participated in the study.

RESULTS

The mean age of the IVF and natural conception groups were 36.22 and 31.08 years, respectively. Nineteen (70.4%) women of the IVF group had a previous medical or gynecological history in contrast to 48 (35.6%) women of the natural conception group. Only 55.6% of the IVF group had a full-term pregnancy unlike 88.1% of women in the natural conception group. An elective c-section was performed in 18 (66.7%) of the women who conceived after IVF, as opposed to 45 (33.3%) of the women who conceived naturally.

CONCLUSION

This cross-sectional study showed that IVF conception was associated with high rates of elective cesarean section as opposed to women with natural conception. The causes of c-sections must be evidence based because the primary cesarean delivery is a major factor contributing to increased c-section rates.

Assisted reproductive technology and hypertensive disorders of pregnancy: systematic review and meta-analyses

Background

Hypertensive disorders of pregnancy (HDP) is one of the most common pregnancy complications and causes of maternal morbidity and mortality. Assisted reproductive technology (ART) has been associated with adverse pregnancy outcomes, including HDP. However, the impact of multiple pregnancies, oocyte donation, as well as fresh and frozen embryo transfer needs to be further studied. We conducted a systematic review and meta-analyses to evaluate the association between ART and HDP or preeclampsia relative to spontaneous conception (SC).

Methods

We identified studies from EMBASE, MEDLINE, and Cochrane Library (up to April 8, 2020) and manually using structured search strategies. Cohort studies that included pregnancies after in vitro fertilization (IVF) with or without intracytoplasmic sperm fertilization (ICSI) relative to SC with HDP or preeclampsia as the outcome of interest were included. The control group was women who conceived spontaneously without ART or fertility medications. The pooled results were reported in odds ratios (OR) with 95% confidence intervals based on random effects models. Numbers needed to harm (NNH) were calculated based on absolute risk differences between exposure and control groups.

Results

Eighty-five studies were included after a screening of 1879 abstracts and 283 full text articles. Compared to SC, IVF/ICSI singleton pregnancies (OR 1.70; 95% CI 1.60–1.80; I² = 80%) and multiple pregnancies (OR 1.34; 95% CI 1.20–1.50; I² = 76%) were both associated with higher odds of HDP. Singleton pregnancies with oocyte donation had the highest odds of HDP out of all groups analyzed (OR 4.42; 95% CI 3.00–6.51; I² = 83%). Frozen embryo transfer resulted in higher odds of HDP (OR 1.74; 95% CI 1.58–1.92; I² = 55%) than fresh embryo transfer (OR 1.43; 95% CI 1.33–1.53; I² = 72%). The associations between IVF/ICSI pregnancies and SC were similar for preeclampsia. Most interventions had an NNH of 40 to 100, while singleton and multiple oocyte donation pregnancies had particularly low NNH for HDP (16 and 10, respectively).

Conclusions

Our meta-analysis confirmed that IVF/ICSI pregnancies are at higher odds of HDP and preeclampsia than SC, irrespective of the plurality. The odds were especially high in frozen embryo transfer and oocyte donation pregnancies.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12884-021-03938-8.

Preterm delivery risk in infertile women who conceived after reproductive surgery: natural conception versus IVF/ICSI

STUDY QUESTION

Is preterm delivery an infertility treatment-related adverse outcome in infertile women who conceived after reproductive surgery?

SUMMARY ANSWER

Compared with matched fertile women, preterm delivery appears to be a modest infertility treatment-related adverse outcome in infertile women who have reproductive surgery then conceived naturally or after IVF/ICSI.

WHAT IS KNOWN ALREADY

Most observational studies have shown that women who receive any infertility treatment are more likely to deliver preterm than do fertile women. However, studies on the outcome of pregnancies in infertile women who conceive naturally after reproductive surgery are scarce.

STUDY DESIGN, SIZE, DURATION

This was a single-centre historical two-part study: cohort and matched cohort study. Anonymized data of 761 infertile women who conceived after reproductive surgery and 758 fertile women were obtained by linking three computerized databases from 1 July 2012 to 31 December 2015.

PARTICIPANTS/MATERIALS, SETTING, METHODS

In the cohort study, we evaluated the association between the mode of conception and preterm delivery <37 and <32 gestational weeks in 703 infertile women, with a singleton pregnancy who conceived after reproductive surgery, using logistic regression adjusted for relevant co-variates to calculate the adjusted odds ratio with a 95% CI. In the matched cohort study, we evaluated preterm delivery as infertility treatment-related adverse outcome using the propensity score (PS) method. The matched cohort comprised 758 infertile women and 758 fertile women with a twin or singleton pregnancy. Infertile women conceived after reproductive surgery either naturally or through IVF/ICSI. Infertile and fertile women were matched using PS matching. Infertile and fertile women were matched for pre-defined risk factors for preterm delivery. Three infertile women out of an original 761 were not included in the analysis because they lacked all required matching variables. We performed a 1:1 matching with an optimal matching algorithm with a caliper width of the linear predictor of 0.1 standard deviations. The effect of reproductive surgery on preterm delivery was evaluated in the PS-matched sample using Pearson's χ2 test and presented as the odds ratio (OR) with 95% CI. All women delivered at the Department of Perinatology, University Medical Centre Ljubljana, Slovenia.

MAIN RESULTS AND THE ROLE OF CHANCE

Among 761 infertile women who conceived after reproductive surgery, 428 (56.2%) women conceived naturally and 333 (43.8%) conceived after IVF/ICSI. The incidence of twin pregnancies was significantly lower after natural conception (2.6% vs 14.1%). Among the 703 infertile women with a singleton pregnancy, 417 (59.3%) conceived naturally and 286 (40.7%) conceived after IVF/ICSI. Adjusted for maternal age and parity in infertile women with singleton pregnancies, IVF/ICSI showed a moderate association with preterm delivery <32 weeks. Compared with natural conception after reproductive surgery, the odds for preterm delivery after IVF/ICSI was 1.07 (95% CI 0.63-1.81) <37 weeks and 2.25 (95% CI 0.80-6.34) <32 weeks. Preterm delivery appears to be a modest infertility treatment-related adverse outcome. Compared with fertile women in the PS-matched sample, infertile women who conceived after reproductive surgery either naturally or after IVF/ICSI the odds of preterm delivery <37 weeks were 1.31 (95% CI 0.97-1.78) and odds of preterm delivery <32 weeks were 1.57 (95% CI 0.78-3.18). However, none of the estimations were statistically significant.

LIMITATIONS, REASONS FOR CAUTION

The main limitations of the study were the retrospective design, the heterogeneity of the types of reproductive surgery performed and underlying reproductive pathologies. The low number of preterm deliveries in the present study might influence the precision of estimations.

WIDER IMPLICATIONS OF THE FINDINGS

The present study aims to alter the prevailing opinion that reproductive surgery should only be considered preceding IVF to increase implantation and pregnancy rates after IVF. It implies that in selected infertile women who have had reproductive surgery, a high rate of natural conception, a low rate of multiple pregnancies, and a modest infertility treatment-related effect on preterm delivery should be the reasons to encourage natural conception after reproductive surgery. Furthermore, by allowing for natural conception, we can avoid a high-cost invasive medical procedure.

STUDY FUNDING/COMPETING INTEREST(S)

The study received no funding. We have no competing interest to declare.

TRIAL REGISTRATION NUMBER

N/A.

Incidence and trend of preterm birth in China, 1990-2016: a systematic review and meta-analysis

OBJECTIVES

To update the WHO estimate of preterm birth rate in China in 1990-2016 and to further explore variations by geographic regions and years of occurrence.

DESIGN

Systematic review and meta-analysis.

DATA SOURCES

Pubmed, Embase, Cochrane Library and Sinomed databases were searched from 1990 to 2018.

ELIGIBILITY CRITERIA

Studies were included if they provided preterm birth data with at least 500 total births. Reviews, case-control studies, intervention studies and studies with insufficient information or published before 1990 were excluded. We estimated pooled incidence of preterm birth by a random effects model, and preterm birth rate in different year, region and by livebirths or all births in subgroup analyses.

RESULTS

Our search identified 3945 records. After the removal of duplicates and screening of titles and abstracts, we reviewed 254 studies in full text and excluded 182, leaving 72 new studies. They were combined with the 82 studies included in the WHO report (154 studies, 187 data sets in total for the meta-analysis), including 24 039 084 births from 1990 to 2016. The pooled incidence of preterm birth in China was 6.09% (95% CI 5.86% to 6.31%) but has been steadily increasing from 5.36% (95% CI 4.89% to 5.84%) in 1990-1994 to 7.04% (95% CI 6.09% to 7.99%) in 2015-2016. The annual rate of increase was about 1.05% (95% CI 0.85% to 1.21%). Northwest China appeared to have the highest preterm birth rate (7.3%, 95% CI 4.92% to 9.68% from 1990 to 2016).

CONCLUSIONS

The incidence of preterm birth in China has been rising gradually in the past three decades. It was 7% in 2016. Preterm birth rate varied by region with the West having the highest occurrence.

Midtrimester amniotic fluid from healthy pregnancies has no microorganisms using multiple methods of microbiologic inquiry

BACKGROUND

There is controversy about whether the amniotic fluid contains bacteria. With the use of sequencing-based methods, recent studies report that the amniotic fluid is colonized by microorganisms. However, background-contaminating DNA might lead to false-positive findings when such a low microbial biomass sample is examined.

OBJECTIVE

The purpose of this study was to determine whether the midtrimester amniotic fluid of patients who subsequently had normal pregnancy outcomes contains a microbial signature.

STUDY DESIGN

In this prospective cohort study, 42 amniotic fluid samples were collected from 37 pregnancies (5 twin and 32 singletons) during genetic amniocentesis in the midtrimester. The subsequent pregnancy outcomes of all the participants were followed. Multiple methods were used to detect the presence of microorganisms in this study, which included cultivation, quantitative real-time polymerase chain reaction, and 16S ribosomal RNA gene sequencing. Multiple positive control samples (n=16) served as quality control samples and included 3 adult fecal samples, 4 vaginal swabs, and 9 artificial bacterial communities that were run in parallel with negative control samples (n=12) that included 4 samples from the hospital operating room and 8 samples from the laboratory, to account for background-contaminating DNA during each step of the experiments.

RESULTS

No bacteria under anaerobic or aerobic conditions or genital mycoplasmas were cultured from any of the amniotic fluid samples. Quantitative polymerase chain reaction did not reveal greater copy numbers of 16S ribosomal RNA gene in amniotic fluid samples than in negative control samples. 16S Ribosomal RNA gene sequencing did not indicate a significant difference in the microbial richness or community structures between amniotic fluid and negative control samples.

CONCLUSION

With multiple methods of microbiologic inquiry, no microorganisms were identified in the midtrimester amniotic fluid of healthy pregnancies with a normal pregnancy outcome.

Outcomes of pulmonary vascular disease in infants conceived with non-IVF fertility treatment and assisted reproductive technologies at 1 year of age

BACKGROUND

Assisted reproductive technologies (ARTs) have been associated with the development of endothelial dysfunction.

OBJECTIVE

To determine potential differences in outcomes associated with pulmonary vascular disease in infants born to mothers receiving any infertility treatment including ART and non-IVF fertility treatments (NIFTs).

DESIGN/METHODS

The sample was derived from an administrative database containing detailed information on infant and maternal characteristics for live-born infants in California (2007-2012) with gestational age (GA) 22 to 44 weeks. Cases were defined as infants with ICD-9 code for pulmonary vascular disease (PVD) and records for ART/NIFT. Controls were randomly selected at a 1:4 ratio. The primary outcome was 1-year mortality. Crude and adjusted odds ratio (OR) with 95% confidence interval (CI) were calculated.

RESULTS

We identified 159 cases and 636 controls. Mothers that utilized ART/NIFT were older, to be of the Caucasian race, to have pre-eclampsia, private insurance, and education >12 years (P < .001). Cases compared to controls were more premature, had lower birth weights, and were more often the product of a multiple gestation pregnancy (P < .001). Cases had a higher 1-year mortality (18.2% vs 9.1%; OR: 2.2; 95% CI: 1.4, 3.6), more severe PVD (86.2% vs 72.3%; OR: 2.4; 95% CI: 1.5, 3.9), and a longer hospital stay (66.7 ± 73.0 vs 32.5 ± 47.2 days; P < .001) than controls. However, when adjusting for GA these differences become statistically insignificant.

CONCLUSION

Children born following ART/NIFT with PVD had increased mortality compared to infants with PVD but without ART/NIFT. The primary driver of this relationship is prematurity.