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Am J Perinatol
DOI: 10.1055/a-2781-7542
Original Article

Perinatal Death in Triplets by Gestational Age: A Retrospective Cohort from Two Tertiary Hospitals

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Abstract

Objective

This study aimed to describe a contemporary cohort of triplet pregnancies from two tertiary centers in a middle-income country and evaluate the association between gestational age (GA) at birth and perinatal death. We developed and internally validated a GA-based risk model.

Study Design

Retrospective cohort from two tertiary hospitals (2015–2024). The unit of analysis was the fetus/neonate, with cluster-robust standard errors at the mother level. Primary outcome: Perinatal death (stillbirth ≥230/7 weeks or neonatal death ≤28 days). GA was modeled with logistic regression using restricted cubic splines; Firth penalization addressed separation where applicable. Internal validation used 200 bootstrap resamples.

Results

The cohort included 150 neonates; perinatal death occurred in 23 (15.4%). Median GA was 33 (31–34) weeks overall, 34.0 (32.0–34.0) in survivors, and 25.0 (24.0–28.0) in perinatal deaths. In the adjusted spline model, GA was the dominant predictor (overall Wald χ2 = 1,473.66, df = 3, p < 0.001; non-linearity χ2 = 424.92, df = 2, p < 0.001), while severe preeclampsia was not significant (χ2 = 0.10, p = 0.750). The category-based Firth model showed markedly elevated odds of perinatal death at earlier gestations versus ≥34 weeks: <28 weeks; adjusted odds ratio (aOR) = 871.15 (95% confidence interval [CI]: 81.25–124,006.80, p < 0.001); 28 to <32 weeks, aOR = 50.22 (5.45–6,682.53, p < 0.001); 32 to <34 weeks, aOR = 5.34 (0.26–804.14, p = 0.278); and severe preeclampsia, aOR = 1.02 (0.09–7.17, p = 0.984). The internally validated model demonstrated excellent discrimination (optimism-corrected area under the receiver operating characteristic curve [AUROC], 0.972) and good overall performance (Brier score, 0.047), with a calibration intercept of −0.129, a slope of 0.696, and a maximum absolute calibration error (E max) of 0.104.

Conclusion

In triplet pregnancies, GA at birth is the dominant determinant of perinatal death, with a steep risk gradient at earlier gestations. A GA-based model demonstrates excellent discrimination and acceptable calibration following bootstrap internal validation, supporting its use in informing counseling and timing-of-delivery decisions in this high-risk population.

Key Points

  • Perinatal mortality in triplet pregnancies decreases sharply after 32 weeks.

  • Most perinatal deaths occur before 32 weeks of gestation.

  • These findings support delivery planning around 32 to 33 weeks.

  • Data from low- and middle-income countries' settings provide guidance for counseling and NICU planning.

  • A simple GA-only model showed excellent discrimination (area under the curve = 0.97).

Keywords

triplet pregnancy - perinatal mortality - gestational age - neonatal intensive care - risk prediction - developing countries

Data Availability Statement

De-identified data and analysis code are available from the corresponding author on reasonable request.


Ethical Approval

Ethical approval was granted by the Institutional Review Board of Alberto Sabogal Sologuren National Hospital, Lima, Peru (approval no.: 684-2025-293).


Informed Consent

Given the retrospective design and de-identified data, the requirement for informed consent was waived per local regulations.


Supplementary Material



Publication History

Received: 05 October 2025

Accepted: 02 January 2026

Accepted Manuscript online:
09 January 2026

Article published online:
20 January 2026

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