STUDY QUESTION: Are the in vitro procedure, ovarian hyperstimulation or a combination of these two associated with blood pressure (BP) of 9-year-old IVF children born to subfertile couples?
SUMMARY ANSWER: Our study demonstrates that ovarian hyperstimulation and the in vitro procedure are not associated with BP values in 9-year-old children born to subfertile couples.
WHAT IS KNOWN ALREADY: Possible long-term effects of IVF on child health and development have been studied relatively little. This is surprising, as it is known that environmental conditions may influence embryonic and foetal development which may result in health related problems in later life. Some studies suggested that IVF is associated with higher BP at pre-school age. Yet, it is unclear whether this may be also true for older children and if so, which component of IVF, i.e. the ovarian hyperstimulation, the embryo culture or a combination of these, attributes to this potentially less favourable BP.
STUDY DESIGN, SIZE, DURATION: The Groningen Assisted Reproductive Technology cohort-study is a prospective assessor-blinded study of children followed from before birth onwards. In total, 170 children were assessed at the age of 9 years. The attrition rate up until the 9-year-old assessment was 21%.
PARTICIPANTS/MATERIALS, SETTING, METHODS: We evaluated cardiovascular health, focusing on BP (in mmHg and the internationally recognized percentiles of the US National High BP Education Program), heart rate and anthropometrics of 57 children born following controlled ovarian hyperstimulation-IVF/ICSI (COH-IVF/ICSI); 47 children born after modified natural cycle-IVF/ICSI (MNC-IVF/ICSI); and 66 children who were conceived naturally by subfertile couples (Sub-NC). Cardiovascular parameters were measured multiple times on one day. In addition, anthropometric data, including BMI and skinfold thickness, were collected.
MAIN RESULTS AND THE ROLE OF CHANCE: Systolic BP in mmHg did not differ between the COH-IVF/ICSI (mean 106.9, SD 6.7), MNC-IVF/ICSI (mean 104.8, SD 5.9) and Sub-NC (mean 106.3, SD 5.3) groups. In addition, systolic BP percentiles did not differ between the groups: COH-IVF/ICSI (mean 62.4, SD 20.2); MNC-IVF/ICSI (mean 56.3, SD 19.3); and Sub-NC (mean 62.3, SD17.8). Also, after adjustment for confounders BP in the three groups was similar. Heart rate and anthropometric values in the three groups did not differ. For instance, BMI values in the COH-IVF/ICSI-children were 16.3 (median value, range 13.0-24.7), in MNC-IVF/ ICSI-children 16.1 (range 12.7-22.5) and in Sub-NC children 16.3 (range 12.7-24.0).
LIMITATIONS, REASONS FOR CAUTION: The size of our study groups does not allow for pertinent conclusions on the effect of ovarian hyperstimulation and the in vitro procedure. The lack of a fertile control group may be regarded as another limitation.
WIDER IMPLICATIONS OF THE FINDINGS: Our study suggests that ovarian hyperstimulation and in vitro procedures are not associated with cardiovascular health in 9-year-old. Yet, BP percentiles of the three groups were higher than the expected 50th percentile. This might indicate that children of subfertile couples have a higher BP than naturally conceived children.
STUDY FUNDING/COMPETING INTEREST(S): The study was financially supported by the University Medical Center Groningen (UMCG), the two graduate schools of the UMCG, BCN, SHARE and the Cornelia Stichting. The sponsors of the study had no role in study design, data collection, data analysis, data interpretation or writing of the report. The authors have no conflicts of interest to declare.