Association of Assisted Reproductive Technology With Offspring Growth and Adiposity From Infancy to Early Adulthood.

Importance: People conceived using assisted reproductive technology (ART) make up an increasing proportion of the world's population. Objective: To investigate the association of ART conception with offspring growth and adiposity from infancy to early adulthood in a large multicohort study. Design, Setting, and Participants: This cohort study used a prespecified coordinated analysis across 26 European, Asia-Pacific, and North American population-based cohort studies that included people born between 1984 and 2018, with mean ages at assessment of growth and adiposity outcomes from 0.6 months to 27.4 years. Data were analyzed between November 2019 and February 2022. Exposures: Conception by ART (mostly in vitro fertilization, intracytoplasmic sperm injection, and embryo transfer) vs natural conception (NC; without any medically assisted reproduction). Main Outcomes and Measures: The main outcomes were length / height, weight, and body mass index (BMI; calculated as weight in kilograms divided by height in meters squared). Each cohort was analyzed separately with adjustment for maternal BMI, age, smoking, education, parity, and ethnicity and offspring sex and age. Results were combined in random effects meta-analysis for 13 age groups. Results: Up to 158 066 offspring (4329 conceived by ART) were included in each age-group meta-analysis, with between 47.6% to 60.6% females in each cohort. Compared with offspring who were NC, offspring conceived via ART were shorter, lighter, and thinner from infancy to early adolescence, with differences largest at the youngest ages and attenuating with older child age. For example, adjusted mean differences in offspring weight were -0.27 (95% CI, -0.39 to -0.16) SD units at age younger than 3 months, -0.16 (95% CI, -0.22 to -0.09) SD units at age 17 to 23 months, -0.07 (95% CI, -0.10 to -0.04) SD units at age 6 to 9 years, and -0.02 (95% CI, -0.15 to 0.12) SD units at age 14 to 17 years. Smaller offspring size was limited to individuals conceived by fresh but not frozen embryo transfer compared with those who were NC (eg, difference in weight at age 4 to 5 years was -0.14 [95% CI, -0.20 to -0.07] SD units for fresh embryo transfer vs NC and 0.00 [95% CI, -0.15 to 0.15] SD units for frozen embryo transfer vs NC). More marked differences were seen for body fat measurements, and there was imprecise evidence that offspring conceived by ART developed greater adiposity by early adulthood (eg, ART vs NC difference in fat mass index at age older than 17 years: 0.23 [95% CI, -0.04 to 0.50] SD units). Conclusions and Relevance: These findings suggest that people conceiving or conceived by ART can be reassured that differences in early growth and adiposity are small and no longer evident by late adolescence.

Second and third trimester fetal ultrasound population screening for risks of preterm birth and small-size and large-size for gestational age at birth: a population-based prospective cohort study

BACKGROUND: Preterm birth, small size for gestational age (SGA) and large size for gestational age (LGA) at birth are major risk factors for neonatal and long-term morbidity and mortality. It is unclear which periods of pregnancy are optimal for ultrasound screening to identify fetuses at risk of preterm birth, SGA or LGA at birth. We aimed to examine whether single or combined second and third trimester ultrasound in addition to maternal characteristics at the start of pregnancy are optimal to detect fetuses at risk for preterm birth, SGA and LGA. METHODS: In a prospective population-based cohort among 7677 pregnant women, we measured second and third trimester estimated fetal weight (EFW), and uterine artery pulsatility and umbilical artery resistance indices as placenta flow measures. Screen positive was considered as EFW or placenta flow measure < 10th or > 90th percentile. Information about maternal age, body mass index, ethnicity, parity, smoking, fetal sex and birth outcomes was available from questionnaires and medical records. Screening performance was assessed via receiver operating characteristic (ROC) curves and area under the curve (AUC) along with sensitivity at different false-positive rates. RESULTS: Maternal characteristics only and in combination with second trimester EFW had a moderate performance for screening for each adverse birth outcome. Screening performance improved by adding third trimester EFW to the maternal characteristics (AUCs for preterm birth 0.64 (95%CI 0.61 to 0.67); SGA 0.79 (95%CI 0.78 to 0.81); LGA 0.76 (95%CI 0.75; 0.78)). Adding third trimester placenta measures to this model improved only screening for risk of preterm birth (AUC 0.72 (95%CI 0.66 to 0.77) with sensitivity 37% at specificity 90%) and SGA (AUC 0.83 (95%CI 0.81 to 0.86) with sensitivity 55% at specificity 90%). Combining second and third trimester fetal and placental ultrasound did not lead to a better performance as compared to using only third trimester results. CONCLUSIONS: Combining single third trimester fetal and placental ultrasound results with maternal characteristics has the best screening performance for risks of preterm birth, SGA and LGA. As compared to second trimester screening, third trimester screening may double the detection of fetuses at risk of common adverse birth outcomes.

Population screening for gestational hypertensive disorders using maternal, fetal and placental characteristics: A population-based prospective cohort study.

OBJECTIVE: To determine screening performance of maternal, fetal and placental characteristics for selecting pregnancies at risk of gestational hypertension and preeclampsia in a low-risk multi-ethnic population. METHOD: In a prospective population-based cohort among 7124 pregnant women, we collected maternal characteristics including body mass index, ethnicity, parity, smoking and blood pressure in early-pregnancy. Fetal characteristics included second and third trimester estimated fetal weight and sex determined by ultrasound. Placental characteristics included first and second trimester placental growth factor concentrations and second and third trimester uterine artery resistance indices. RESULTS: Maternal characteristics provided the best screening result for gestational hypertension (area-under-the-curve [AUC] 0.79 [95% Confidence interval {CI} 0.76-0.81]) with 40% sensitivity at 90% specificity. For preeclampsia, the maternal characteristics model led to a screening performance of AUC 0.74 (95% CI 0.70-0.78) with 33% sensitivity at 90% specificity. Addition of second and third trimester placental ultrasound characteristics only improved screening performance for preeclampsia (AUC 0.78 [95% CI 0.75-0.82], with 48% sensitivity at 90% specificity). CONCLUSION: Routinely measured maternal characteristics, known at the start of pregnancy, can be used in screening for pregnancies at risk of gestational hypertension or preeclampsia within a low-risk multi-ethnic population. Addition of combined second and third trimester placental ultrasound characteristics only improved screening for preeclampsia.