Impact de l'âge gestationnel et du poids de naissance sur le devenir cardiovasculaire à long terme

Ambient climatic factors and term birthweight: A study of critical windows of exposure in the Republic of Cyprus

BACKGROUND

Reduced birthweight is associated with adverse perinatal and long-term outcomes. A few studies examined the association between climatic factors and birthweight with inconsistent results probably due to differences in exposure assessment, statistical models, climatic parameters, and study populations.

METHODS

We obtained data from the Republic of Cyprus birth registry from 2007 to 2020, and matched climatic exposures (i.e., temperature, relative humidity, temperature variability, humidity variability) by the hospital district at birth. We used distributed lag models to examine the association between term birthweight, temperature, humidity, and their variability to identify critical windows. Our models were adjusted for coarse particulate matter level (≤10 μm [PM10), and individual-level covariates. Subgroup analysis was conducted to examine effect modification by maternal age and education.

RESULTS

We identified two critical windows of exposure to ambient temperature at early and late pregnancy. The cumulative change of birthweight per 5 °C increases in mean weekly temperature was -57.27 (2%) (95% Confidence Interval [CI]: 99.62 (3.1%), -14.92 (0.5%)) and -79.2 (2.5%) (95%CI: 117.03 (3.5%), -41.52 (1.3%)) grams during weeks 1-8 and weeks 28-37, respectively. There was no significant effect of humidity, temperature variability, or humidity variability on birthweight. Based on subgroup analysis, mothers with post-secondary education were more sensitive to temperature, but the marginal significance of differences in effect estimates may be linked with differences in sample size.

CONCLUSION

Our study suggests that higher ambient temperature exposure during early and late pregnancy is associated with lower birthweight in main and subgroup analysis. The findings demonstrate in a country highly impacted by climate change like Cyprus that rising temperatures may be associated with perinatal outcomes in susceptible populations during sensitive windows of exposure.

In adolescence, extreme prematurity is associated with significant changes in the microvasculature, elevated blood pressure and increased carotid intima-media thickness

OBJECTIVES

Increased carotid intima-media thickness (cIMT) and loss of capillary density are antecedents of cardiovascular disease in adults. Former preterm infants are at risk for metabolic precursors of vascular disease, but vascular changes have not yet been studied in this population.

PATIENTS AND METHODS

In 54 former preterm (birth weigh (BW) 753±152 g) and 12 term children (BW 3395±558 g), functional vessel density (FVD) on the forearm and cIMT were obtained at a mean (±SD) age of 11.8±1.5 years. FVD was measured using sidestream dark field imaging before, during and after arterial occlusion, and cIMT using high resolution B-mode ultrasonography. Statistical comparisons were made using the t test, Mann-Whitney U test and the sign test for symmetry, with a two-sided p value as appropriate.

RESULTS

The systolic blood pressure of the former preterm children was significantly increased compared to reference values (females 119±8, z score 1.23; males 118±11, z score 1.14 mm Hg), as were the cIMT values (0.45±0.03 mm vs 0.38±0.04 mm; p<0.001). FVD was significantly higher in former preterm children compared to controls at baseline (mean±SD 33.6±14.5 cm/cm(2) vs 23.0±7.1 cm/cm(2); p=0.002) with decreased reactivity during arterial occlusion (χ(2) 7.14, p=0.008).

CONCLUSIONS

Preterm birth is associated with significant permanent alteration in the microcirculation and increased cIMT and systolic blood pressure. It is unknown whether these changes are due to preterm birth and rapid maturation of the skin or to nutritional factors, as previously thought. This is an important area of future research.

[Medical assessment after a pre-eclampsia: why? for whom? when? how? for what purpose?]

The internist has a relevant role in the medical assessment which is mandatory after every case of pre-eclampsia. This postnatal visit has to be performed to assert there is no underlying disorder such as chronic arterial hypertension or nephropathy, autoimmune disease or thrombophilia. This visit is also needed to provide information to the woman about what occurred during the pregnancy as well as to consider which would have to be done in case of a subsequent pregnancy. Long-term outcome had also to be taken into account considering risks for cardiac, arterial, renal and metabolic diseases. This visit is of outmost importance after very early-onset pre-eclampsia, and especially if it has already occurred. The postnatal visit after pre-eclampsia represents a very demonstrative example of the role that the internist can afford to the obstetrician in the management of medical disorders occurring during pregnancy and needing a specific expertise as well as a long-term follow-up.