Maternal prenatal cholesterol levels predict offspring weight trajectories during childhood in the Norwegian Mother, Father and Child Cohort Study

Association between maternal blood lipids during pregnancy and offspring growth trajectories in a predominantly macrosomic cohort: findings from the ROLO longitudinal birth cohort study

The purpose of this study is to examine associations between maternal lipid profiles in pregnancy and offspring growth trajectories in a largely macrosomic cohort. This is a secondary analysis of the ROLO birth cohort (n = 293), which took place in the National Maternity Hospital, Dublin, Ireland. Infants were mostly macrosomic, with 55% having a birthweight > 4 kg. Maternal mean age was 32.4 years (SD 3.9 years), mean BMI was 26.1 kg/m2 (SD 4.4 kg/m2) and 48% of children born were males. Total cholesterol, high density lipoprotein cholesterol (HDL-cholesterol), low density lipoprotein cholesterol (LDL-cholesterol) and triglycerides were measured from fasting blood samples of mothers at 14 and 28 week gestation. The change in maternal lipid levels from early to late pregnancy was also examined. Offspring abdominal circumference and weight were measured at 20- and 34-week gestation, birth, 6 months, 2 years and 5 years postnatal. Linear spline multilevel models examined associations between maternal blood lipid profiles and offspring growth. We found some weak, significant associations between maternal blood lipids and trajectories of offspring growth. Significant findings were close to the null, providing limited evidence. For instance, 1 mmol/L increase in maternal triglycerides was associated with faster infant weight growth from 20- to 34-week gestation (0.01 kg/week, 95% CI - 0.02, - 0.001) and slower abdominal circumference from 2 to 5 years (0.01 cm/week, 95% CI - 0.02, - 0.001). These findings do not provide evidence of a clinically meaningful effect.    Conclusion: These findings raise questions about the efficacy of interventions targeting maternal blood lipid profiles in pregnancies at risk of macrosomia. New studies on this topic are needed. What is Known: • Maternal fat accumulation during early pregnancy may potentially support fetal growth in the third trimester by providing a reserve of lipids that are broken down and transferred to the infant across the placental barrier. • There are limited studies exploring the impact of maternal lipid profiles on infant and child health using growth trajectories spanning prenatal to postnatal life. What is New: • Maternal blood lipid profiles were not associated with offspring growth trajectories of weight and abdominal circumference during pregnancy up to 5 years of age in a largely macrosomic cohort, as significant findings were close to the null, providing limited evidence for a clinically meaningful relationship. • Strengths of this work include the use of infant growth trajectories that span prenatal to postnatal life and inclusion of analyses of the change of maternal lipid levels from early to late pregnancy and their associations with offspring growth trajectories from 20-week gestation to 5 years of age.

Overweight or obesity in children born after assisted reproductive technologies in Denmark: A population-based cohort study

BACKGROUND

The association between assisted reproductive technologies (ARTs) and the body mass index (BMI) of children remains controversial. Confounding by morbidity and other factors associated with parental infertility may have biased studies comparing children born after ART with children born after no treatment. We investigated the associations between different fertility treatments and BMI in children at age 5 to 8 years, adjusting for and stratifying by causes of parental infertility.

METHODS AND FINDINGS

This Danish cohort study included 327,301 children born between 2007 and 2012 (51% males, median age at follow-up 7 years). Of these, 13,675 were born after ART, 7,728 were born after ovulation induction with or without intrauterine insemination [OI/IUI], and 305,898 were born after no fertility treatments. Using the International Obesity Task Force (IOTF) standards, we defined overweight (BMI ≥ IOTF-25) and obesity (BMI ≥ IOTF-30). We compared children born after ART versus OI/IUI; intracytoplasmic sperm injection (ICSI) versus conventional in vitro fertilization (IVF); and frozen-thawed versus fresh embryo transfer and estimated crude and adjusted prevalences of children with overweight or obesity at age 5 to 8 years, prevalence odds ratios (PORs), and differences in mean BMI z-scores. Adjustment was performed using stabilized inverse probability of treatment weights, including parity, year of conception, parental causes of infertility, age, educational level, comorbidities, maternal country of origin, BMI, and smoking as covariates. The crude prevalence of obesity was 1.9% in children born after ART, 2.0% in those born after OI/IUI, and 2.7% in those born after no fertility treatment. After adjustment, children born after ART and OI/IUI had the same prevalence of being overweight (11%; POR 1.00, 95% confidence interval [CI] 0.91 to 1.11; p = 0.95) or obese (1.9%; POR 1.01, 95% CI 0.79 to 1.29; p = 0.94). Comparison of ICSI with conventional IVF yielded similar pattern (POR 0.95, 95% CI 0.83 to 1.07; p = 0.39 for overweight and POR 1.16, 95% CI 0.84 to 1.61; p = 0.36 for obesity). Obesity was more prevalent after frozen-thawed (2.7%) than fresh embryo transfer (1.8%) (POR 1.54, 95% CI 1.09 to 2.17; p = 0.01). The associations between fertility treatments and BMI were only modestly different in subgroups defined by the cause of infertility. Study limitations include potential residual confounding, restriction to live births, and lack of detailed technical information about the IVF procedures.

CONCLUSIONS

We found no association with BMI at age 5 to 8 years when comparing ART versus OI/IUI or when comparing ICSI versus conventional IVF. However, use of frozen-thawed embryo transfer was associated with a 1.5-fold increased risk of obesity compared to fresh embryo transfer. Despite an elevated relative risk, the absolute risk difference was low.