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First trimester growth delay in trisomy 18
1Mount Sinai Medical Center, Department of Obstetrics, Gynecology, and Reproductive Science, New York, New York 10029.
Insights
First-trimester growth delay in fetuses may indicate trisomy 18 (an abnormal chromosome number). Early detection of this growth pattern can aid in identifying trisomy 18 in pregnant individuals.
Area of Science:
- Prenatal diagnostics
- Genetics
- Maternal-fetal medicine
Background:
- Neonates with trisomy 18 often exhibit intrauterine growth restriction.
- Delayed fetal growth is typically identified in the second and third trimesters for trisomy 18.
- First-trimester growth assessment for trisomy 18 has not been extensively studied.
Purpose of the Study:
- To investigate first-trimester fetal growth patterns in trisomy 18.
- To compare growth in trisomy 18 fetuses with normal controls during early gestation.
- To determine if first-trimester growth delay is a potential marker for trisomy 18.
Main Methods:
- Ultrasound examination of five fetuses with confirmed trisomy 18.
- Measurement of crown-rump length (CRL) in the first trimester.
- Comparison of CRL measurements against a control group of 16 normal fetuses.
Main Results:
- All five fetuses with trisomy 18 showed a significant growth delay, with CRL at least 5 days smaller than expected (mean delay 8.2 days).
- Only two fetuses in the control group exhibited a similar growth delay (p < 0.005).
- This suggests a statistically significant difference in early growth between trisomy 18 and normal fetuses.
Conclusions:
- Significant first-trimester growth delay, when gestational age is certain, may serve as an early indicator for trisomy 18.
- This finding could potentially improve early detection rates for trisomy 18.
- Further research is warranted to validate this early growth marker in larger cohorts.
Abstract:
Neonates with trisomy 18 are usually growth retarded at birth, and delayed growth has been ultrasonigraphically detected antenatally during the second and third trimesters in fetuses with this aneuploidy. We examined the growth patterns of five fetuses with trisomy 18 during the first trimester and compared them with a group of 16 normal control subjects. The crown-rump length of all trisomy 18 fetuses was at least 5 days smaller than expected (mean, 8.2 days; range 5 to 11 days), whereas only two controls had a similar delay (p less than 0.005). We conclude that in patients in whom gestational age is certain by other parameters, significant growth delay detected during the first trimester may be a useful marker for trisomy 18.