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Updated: May 23, 2026
06:55
Assessment of Maternal Vascular Remodeling During Pregnancy in the Mouse Uterus
Published on: December 5, 2015
A systematic review to calculate background miscarriage rates using life table analysis
Lyndsay Ammon Avalos1, Claudia Galindo, De-Kun Li
1Division of Research, Kaiser Permanente, Oakland, California, USA. Lyndsay.A.Avalos@kp.org
Summary
This study calculated miscarriage risk by gestational week. Early pregnancy (before 14 weeks) shows higher miscarriage rates, with cumulative risk between 11-22% from weeks 5-20.
Area of Science:
- Reproductive Health
- Perinatology
- Epidemiology
Background:
- Miscarriage is a common pregnancy complication.
- Accurate risk assessment by gestational week is crucial for patient counseling.
- Existing data may lack detailed weekly risk stratification.
Purpose of the Study:
- To calculate expected miscarriage rates by gestational week (5-20).
- To determine the cumulative risk of miscarriage during early gestation.
- To estimate the remaining risk of miscarriage throughout the first 20 weeks.
Main Methods:
- Systematic literature review of MEDLINE and reference lists.
- Inclusion of studies with gestational age at entry, outcome, and outcome timing.
- Application of Life Table Analysis Methods for risk calculation.
Main Results:
- Weekly miscarriage rates exceeded 20 per 1000 woman-weeks before week 13.
- Rates decreased below 10 per 1000 woman-weeks by week 14.
- Cumulative miscarriage risk (weeks 5-20) ranged from 11% to 22%.
Conclusions:
- Significant variation in miscarriage rates and risks observed in early gestation (<14 weeks).
- Data provide a range of background miscarriage rates, cumulative, and remaining risks by gestational week.
- Findings aid in understanding and counseling regarding early pregnancy loss risk.
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