Effect of Advanced Maternal Age on Pregnancy Outcomes and Vascular Function in the Rat
Bibliographic record
Abstract
Advanced maternal age is becoming increasingly common in Western societies and is associated with increased maternal and fetal morbidity and mortality. We hypothesized that aging results in impaired vascular function in pregnancy because of increased vascular oxidative stress and resultant scavenging of nitric oxide in both uterine and systemic arteries, causing reduced uteroplacental perfusion and poor pregnancy outcomes. Using aged rats (9.5 months), we investigated the effect of a delayed first natural pregnancy on pregnancy outcomes and uterine and mesenteric artery function on gestational day 20. Delayed pregnancy in the rat reduced fertility by 46%, reduced litter size by 36%, caused fetal growth restriction, increased placental weight, and increased maternal systolic blood pressure (by 16 mm Hg). Uterine arteries from aged dams displayed reduced constriction to phenylephrine (young: 14.3±0.94 mN/mm versus aged: 11.4±0.5 mN/mm, P=0.02) and potassium chloride (124 mmol/L; young: 21.8±1.27 mN/mm versus aged: 14.2±1.7 mN/mm; P=0.01). Methacholine-induced vasodilation was similar in uterine arteries from young and aged dams. However, mesenteric arteries from aged dams had a greater nitric oxide and a reduced endothelial-derived hyperpolarization contribution to methacholine-mediated vasodilation compared with young dams. Both uterine and mesenteric arteries from aged dams had greater active myogenic responses, with area under the curve increased by 228% and 151%, in aged uterine and mesenteric arteries, respectively. These results demonstrate that vascular function is altered at an advanced maternal age and provides further insights into the risks of poor pregnancy outcomes observed in women who delay pregnancy.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.001 |
| Insufficient payload (model declined to judge) | 0.001 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".