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Published on: June 29, 2013
Timing and Severity of Fetal Growth Restriction Diagnosis and Association with Perinatal Morbidity
Lilian N Bui1, Sonia Ahluwalia2, Nkechinyelum Q Ogu1
1Department of Obstetrics and Gynecology, Division of Maternal-Fetal Medicine, Northwestern University Feinberg School of Medicine, Chicago, Illinois, United States.
Insights
Severe fetal growth restriction (FGR), diagnosed early or late, increases risks for hypertensive disorders, preterm birth, and small-for-gestational age. However, FGR classifications show poor ability to predict these adverse pregnancy outcomes.
Area of Science:
- Maternal-Fetal Medicine
- Obstetrics
- Neonatology
Background:
- The Society of Maternal Fetal Medicine updated fetal growth restriction (FGR) diagnostic criteria in 2020, categorizing it by onset (early vs. late) and severity (mild vs. severe).
- Understanding the impact of these refined criteria on predicting adverse pregnancy outcomes is crucial for clinical management.
Purpose of the Study:
- To assess the association between timing and severity of FGR diagnosis and adverse pregnancy outcomes.
- To evaluate the discriminatory ability of different FGR classifications in identifying these outcomes.
Main Methods:
- Retrospective cohort study of singleton pregnancies with sonographic FGR diagnosis (May 2020-December 2021).
- Four FGR groups: early-onset severe, early-onset mild, late-onset severe, and late-onset mild.
- Multivariable logistic regression and ROC analysis were used to assess associations and predictive abilities.
Main Results:
- Early-onset severe FGR was associated with higher odds of hypertensive disorders of pregnancy, preterm birth, and small-for-gestational age compared to late-onset mild FGR.
- Late-onset severe FGR also showed increased odds of preterm birth and small-for-gestational age.
- Mild FGR, regardless of onset, had similar odds of adverse outcomes, and all FGR classifications demonstrated poor discriminatory ability for predicting these outcomes.
Conclusions:
- Both early- and late-onset severe FGR are linked to adverse pregnancy outcomes, but their ability to predict these outcomes is limited.
- Early-onset severe FGR specifically correlates with hypertensive disorders of pregnancy.
- Severe FGR, irrespective of timing, elevates the risk of preterm birth and small-for-gestational age, though predictive accuracy remains low across all classifications.
Objective:
In 2020, the Society of Maternal Fetal Medicine refined fetal growth restriction (FGR) diagnostic criteria by temporal (early-, <32 weeks 0 days [320] weeks; late-onset, ≥320 weeks) and measurement-specific definitions (severe, estimated fetal weight <3rd; mild, estimated fetal weight 3rd-9th percentile and/or abdominal circumference <10th percentile). Using these updated clinical definitions, we sought to determine the association of timing and severity of FGR diagnosis with, and their discriminatory ability for, adverse pregnancy outcomes.
Study Design:
This retrospective cohort study included singleton, non-anomalous pregnancies with sonographic FGR diagnosis at ≥180 weeks' gestation from May 2020 to December 2021. We evaluated four FGR classification exposure groups: (1) early-onset, severe FGR; (2) early-onset, mild FGR; (3) late-onset, severe FGR; and (4) late-onset, mild FGR. Outcomes assessed were hypertensive disorders of pregnancy, preterm birth, and small-for-gestational age. Multivariable logistic regression estimated the odds of each outcome associated with each exposure, adjusted for maternal age, insurance, and parity. Receiver-operating characteristic analysis determined test characteristics for the ability of these FGR classification groups to identify the postnatal outcomes, using late-onset, mild FGR as the reference group.
Results:
Among 566 eligible pregnancies, early-onset, severe FGR had higher adjusted odds of hypertensive disorders of pregnancy (aOR = 1.3, 95% CI: 1.1-1.7), preterm birth (aOR = 2.1, 95% CI: 1.6-2.6), and small-for-gestational age (aOR = 1.6, 95% CI: 1.3-1.9), compared to late-onset, mild FGR. Late-onset, severe FGR also had higher adjusted odds of preterm birth (aOR = 7.2, 95% CI: 2.9-18.3) and small-for-gestational age (aOR = 5.8, 95% CI: 2.5-13.6). Odds of adverse pregnancy outcomes were similar with early- and late-onset mild FGR. Overall, discriminatory ability of these FGR classification groups for adverse pregnancy outcomes were poor.
Conclusion:
Early- and late-onset, severe FGR (versus late-onset, mild FGR) are positively associated with, but have poor discriminatory ability for, adverse pregnancy outcomes.
Key Points:
· Early-onset, severe FGR (vs. late-onset, mild FGR) is significantly associated with hypertensive disorders of pregnancy.. · Compared to late-onset mild FGR, severe FGR, whether early- or late-onset, has greater odds of preterm birth and small-for-gestational age.. · All FGR classification groups had weak discriminatory ability for identification of these adverse pregnancy outcomes..
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