Fetal cardiac function at midgestation and conception by in-vitro fertilization

Investigation of cardiac remodeling and cardiac function on fetuses conceived via artificial reproductive technologies: a review

The prevalence of artificial reproductive technologies (ART), such as intra-uterine insemination (IUI), in vitro fertilization (IVF), and intracytoplasmic sperm injection (ICSI), has surged in response to the global increase in infertility rates, now impacting 17.5 % of couples. With over nine million babies born through ART, the safety and efficacy of these methods are largely recognized; however, emerging concerns regarding their association with prenatal and long-term health risks, especially cardiovascular disease (CVD), necessitate a thorough examination. This review synthesizes recent findings on the cardiac remodeling observed in ART-conceived fetuses, highlighting the potential for sub-clinical dysfunction and subsequent cardiovascular anomalies that may extend into adolescence. It delves into the perinatal complications linked to ART and examines the contribution of the renin-angiotensin system, epigenetic modifications, and altered microRNA expressions to fetal cardiovascular development. The analysis further differentiates the cardiac effects of fresh vs. frozen ART cycles and investigates the enduring nature of these changes beyond birth. Addressing the elevated CVD risk among ART individuals, the review suggests proactive measures, including lifestyle adjustments initiated early in life, to mitigate potential adverse outcomes. It emphasizes the critical need for ongoing research and intervention strategies to safeguard the cardiovascular health of the increasing number of ART-conceived individuals.

Fetal Cardiac Function and Remodeling in In Vitro Fertilization Pregnancies: A Tertiary Center Experience

PURPOSE

To investigate fetal cardiac functions and remodeling in pregnancies conceived via in vitro fertilization (IVF).

METHODS

This prospective case-control study included 40 singleton IVF pregnancies and 46 uncomplicated control pregnancies at 28-36 weeks of gestation. The IVF group consisted of pregnancies applied to the outpatient clinic, excluding those with anatomical or chromosomal abnormalities. Fetal cardiac morphological measurements, left myocardial performance index (MPI), cardiac output, spectral, tissue Doppler, and M-mode measurements were recorded. Ventricular and great vessel size were assessed for fetal cardiac morphology, while MPI, spectral Doppler, and tissue Doppler parameters were assessed for cardiac function.

RESULTS

The right atrial area was statistically increased and the right ventricular basal sphericity index was statistically decreased in the IVF group. The mitral and aortic valves were smaller in the IVF group, while tricuspid and pulmonary valve measurements were similar. Left ventricular ejection time was statistically lower in the IVF group, although the MPI was similar. The IVF group had a higher right fetal MPI on tissue Doppler imaging, but the difference was not statistically significant.

CONCLUSION

This study suggests that IVF pregnancies may demonstrate some effects of fetal cardiac remodeling and mild systolic dysfunction.

Subclinical cardiac impairments in fetuses conceived through assisted reproductive technology by speckle tracking echocardiography

OBJECTIVES

To evaluate the changes of cardiac morphology and function in fetuses conceived through assisted reproductive technologies (ART) by speckle tracking echocardiography.

METHODS

A retrospective study was conducted in 101 spontaneously conceived (SC) fetuses and 99 ART-conceived ones. Fetal echocardiography was performed, fetal cardiac morphology and function were analyzed using two-dimensional speckle tracking software, including global sphericity index (GSI), global longitudinal strain (GLS), fractional area change (FAC) of the left and right ventricles, as well as segmental sphericity index (SI), end-diastolic diameter (ED), and fractional shortening (FS) in 24 segments.

RESULTS

Compared to the SC fetuses, the ART-conceived fetuses exhibited decreased GSI (median [interquartile range], 1.22 [1.16-1.27] vs. 1.18 [1.11-1.24], p=0.007), decreased right ventricular GLS (24.9 [21.5-27.6] vs. 23.2 [20.4-26.8], p=0.026), and decreased right ventricular FAC (mean ± standard deviation, 39.7 ± 6.4 vs. 37.2 ± 7.1, p=0.003). Analysis of the 24 segments showed that ART-conceived fetuses had reduced SI in the apical segments of right ventricle and increased ED in several segments of the right ventricle.

CONCLUSIONS

Fetuses conceived through ART had a more spherical shape of the global heart and predominantly right-sided cardiac remodeling and systolic function impairment.

Ultrasound evaluation of the cardiovascular system in offspring conceived through assisted reproductive technology

With the widespread application of assisted reproductive technology, the health issues of offspring conceived through assisted reproductive technology have also received increasing attention. Animal experiments and clinical studies have found subclinical adverse changes in the cardiovascular system of assisted reproductive offspring. Assisted reproductive technology itself may be just one of the many factors contributing to this phenomenon, with epigenetics playing an important role. Ultrasound technology can be used to assess the morphological structure and function of the cardiovascular system in assisted reproductive offspring from the fetal stage, providing the possibility to study the potential cardiovascular damage in this large population. This review aims to explore the effects and mechanisms of assisted reproductive technology on the cardiovascular system of offspring and provide a review of the research progress in ultrasound technology in this area.

Subfertility versus ART: unraveling the origins of fetal cardiac programming

STUDY QUESTION

Do spontaneously conceived (SC) fetuses from subfertile couples show the same signs of cardiac remodeling as those observed after IVF treatments?

SUMMARY ANSWER

As opposed to fetuses from IVF, SC fetuses from subfertile couples do not show cardiac remodeling and present a similar cardiac structure and function to those of SC fetuses from fertile couples.

WHAT IS KNOWN ALREADY

Subjects conceived by IVF present signs of cardiac remodeling and suboptimal function in utero and during childhood, including larger atria, more globular and thicker ventricles, reduced longitudinal motion, and impaired relaxation as compared to SC individuals from fertile couples. There are no previous publications investigating the independent cardiac programming effects of infertility in SC fetuses from subfertile couples (with time-to-pregnancy (TTP) over 12 months).

STUDY DESIGN, SIZE, DURATION

A prospective cohort study of 289 singleton pregnancies exposed and not exposed to subfertility recruited from 2019 to 2021, including 96 SC pregnancies from fertile couples (TTP under 12 months), 97 SC from subfertile couples (TTP over 12 months), and 96 from IVF after fresh embryo transfer. Fetal echocardiography was performed in all pregnancies. Epidemiological data and perinatal outcomes were collected in all pregnancies. The overall attrition rate was 15.7%.

PARTICIPANTS/MATERIALS, SETTING, METHODS

SC from subfertile couples and IVF pregnancies were identified as eligible at pregnancy diagnosis, and eligible SC pregnancies from fertile couples who attended our maternal-fetal unit were invited to participate at third trimester, being matched to the other groups by maternal age. Fetal echocardiography was performed at 29-34 weeks of pregnancy to assess cardiac structure and function, and results were adjusted by parental age, maternal smoking status, child's birth order, birthweight centile, gestational age, and estimated fetal weight at scan.

MAIN RESULTS AND THE ROLE OF CHANCE

Parental age, ethnicity, BMI, and smoking exposure, median gestational age and estimated fetal weight were similar in all study groups. There were no significant differences in infertility duration or etiology between the subfertile and the IVF populations (TTP: subfertile median 35 months (interquartile range 20-48) versus IVF: 47 (25-61); P-value = 0.051). While both fertile and subfertile SC groups presented similar fetal cardiac results, IVF fetuses showed larger atria (right atria-to-heart ratio: IVF mean 18.9% (SD 3.4) versus subfertile 17.8% (3.5) versus fertile 17.6% (3.3); adjusted P-value < 0.001), more globular ventricles (right ventricular sphericity index: IVF 1.56 (0.25) versus subfertile 1.72 (0.26) versus fertile 1.72 (0.26); <0.001), and thicker myocardial walls (relative wall thickness: IVF 0.86 (0.22) versus subfertile 0.64 (0.13) versus fertile 0.64 (0.18); <0.001). Whereas SC fetuses from fertile and subfertile couples had preserved cardiac function, IVF fetuses showed signs of suboptimal systolic and diastolic function, with reduced tricuspid ring displacement (IVF 7.26 mm (1.07) versus subfertile 8.04 mm (1.18) versus fertile 7.89 mm (1.51); <0.001) and increased left myocardial performance index (IVF 0.49 (0.08) versus subfertile 0.45 (0.09) versus fertile 0.45 (0.10); <0.001). A sub-analysis including only unexplained infertility cases in subfertile SC and IVF groups showed similar results.

LIMITATIONS, REASONS FOR CAUTION

The fetal cardiac changes reported here are subclinical, and most of the cardiovascular parameters were within normal ranges. Although echocardiographic changes are recognized as potential cardiovascular risk factors, their association with long-term cardiovascular disease remains to be demonstrated.

WIDER IMPLICATIONS OF THE FINDINGS

Subfertility per se does not seem to be associated to fetal cardiac remodeling, which has been previously described in IVF fetuses. Future studies are warranted to further investigate other factors related to the observed fetal cardiac changes associated with ART.

STUDY FUNDING/COMPETING INTEREST(S)

This project has been partially funded with support from the Erasmus + Programme of the European Union (Framework Agreement number: 2013-0040). This publication reflects the views only of the author, and the Commission cannot be held responsible for any use, which may be made of the information contained therein. Additionally, the research leading to these results has received funding from 'la Caixa' Foundation under grant agreement LCF/PR/GN18/10310003, the Instituto de Salud Carlos III (PI15/00130, PI16/00861, PI17/00675, PI18/00073, INT21/00027)-co-funded by the European Union, Cerebra Foundation for the Brain Injured Child (Carmarthen, Wales, UK) and AGAUR 2017 SGR grant no 1531. The authors have no conflicts of interest to declare.

TRIAL REGISTRATION NUMBER

N/A.