Relationship between first trimester fetal crown-rump length and birth weight

Objective: We aimed to investigate the relationship between the difference between the expected and detected Crown-Rump Length (CRL) values at the 11th to 14th weeks of the gestation and the birth weight of the newborn. Material and Method: Our study was performed retrospectively with 1361 pregnancies who applied to our hospital for the first trimester screening test between 2013 and 2016 at their 11th to 14th gestational weeks. Patients were studied in three groups according to the difference between the expected and the determined CRL size. Group A (n: 266) was conducted if the CRL was smaller than expected (difference between expected and detected CRL size is 2 to 6 days), Group B (n: 695) was conducted if the CRL was normal (difference is 1 day less, equal or more than 1 day), Group C (n: 400) was conducted if the CRL was bigger than expected (the difference is 2-6 days less). The difference between the detected CRL values and the abnormal birth weight relation was assessed. Results: The birth weight of the newborn was detected statistically difference between only two groups (between Group A and C, between Group B and C). According to this, the birth weight of Group C cases (3534,57 ± 461,76 g) was statistically higher than Group A (3271,37 ± 486,94 g) (p = 0.0001). The birth weight of Group C cases (3534,57 ± 461,76 g) was significantly higher than Group B (3307,56 ± 352,51 g) (p = 0.0001). There were statistically significant LGA fetuses in Group C (p = 0.0001). The highest LGA ratio was found in Group C (14.5%); and the lowest LGA rate in Group B (2.6%). Conclusion: Detection of expected large or small values in CRL size during early gestation period should be a warning signal in terms of abnormal birth weight complications and these should be followed up more strictly by antenatal follow up