Severe Maternal and Neonatal Morbidity Among Gestational Carriers
Bibliographic record
Abstract
BACKGROUND: Use of a gestational ("surrogate") carrier is increasingly common. Risk for maternal and neonatal adversity is largely unknown in this birthing population. OBJECTIVE: To determine the risk for severe maternal morbidity (SMM) and severe neonatal morbidity (SNM) in gestational carriers. DESIGN: Population-based cohort study. SETTING: All of Ontario, Canada. PARTICIPANTS: All singleton births at more than 20 weeks' gestation, from 2012 to 2021. MEASUREMENTS: Exposure was type of conception, namely, gestational carriage (main exposure), unassisted conception (comparison group 1), and in vitro fertilization (IVF) (comparison group 2). Main composite outcomes were SMM and SNM. Modified Poisson regression models generated weighted relative risks (wRRs) using propensity score-based overlap weighting. Secondary outcomes included hypertensive disorders of pregnancy, cesarean delivery, preterm birth, and postpartum hemorrhage. RESULTS: Of all eligible singleton births, 846 124 (97.6%) were by unassisted conception, 16 087 (1.8%) by IVF, and 806 (0.1%) by gestational carriage. Respective risks for SMM were 2.3%, 4.3%, and 7.8%. The wRRs were 3.30 (95% CI, 2.59 to 4.20) comparing gestational carriage with unassisted conception and 1.86 (CI, 1.36 to 2.55) comparing gestational carriage with IVF. Respective risks for SNM were 5.9%, 8.9%, and 6.6%, generating wRRs of 1.20 (CI, 0.92 to 1.55) for gestational carriage versus unassisted conception and 0.81 (CI, 0.61 to 1.08) for gestational carriage versus IVF. Hypertensive disorders, postpartum hemorrhage, and preterm birth at less than 37 weeks were also significantly higher contrasting gestational carriers to either comparison group. LIMITATION: Absence of information about indications for choosing a gestational carrier, and oocyte or sperm donor source. CONCLUSION: Among singleton births of more than 20 weeks' gestation, a higher risk for SMM and adverse pregnancy outcomes was seen among gestational carriers compared with women who conceived with and without assistance. Although gestational carriage was associated with preterm birth, there was less clear evidence of severe neonatal morbidity. Potential mechanisms for higher maternal morbidity among gestational carriers require elucidation, alongside developing special care plans for gestational carriers. PRIMARY FUNDING SOURCE: The Canadian Institutes of Health Research.
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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 | 0.001 | 0.002 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.001 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| 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".