Development of Fetal Intestinal Length during 2nd-Trimester in Normal and Pathologic Pregnancies

Abstract

Linear growth of the human fetal gastrointestinal tract is not often discussed in the literature, and little is known about the effects of chromosomal abnormalities and intrauterine growth restriction (IUGR) on intestinal length, especially during the 2nd trimester. Accurate evaluation of intestinal length and knowledge of normal and reference values are of clinical importance. For example, intestinal resection may be necessary in preterm infants with necrotizing enterocolitis or mid-gut volvulus, and the surgeon should use data to be judicious in the amount removed. Linear measurements are essential in evaluating fetal development ultrasonographically and are an integral part of the postmortem examination. The intestinal lengths of 203 2nd-trimester fetuses and premature infants were measured. Small intestine length (SIL), colon length (CL), total bowel length (TBL; TBL = SIL + CL), and the length of the appendix (AL) increased with gestational age. No differences between the genders were observed. Colon length increased secondary to maceration, but no such effects were shown on SIL, TBL, or AL. No differences were shown in relation to IUGR. Small intestine length, CL, and TBL, but not AL, were shorter in fetuses with trisomy 21. Appendix length was not affected by any of the studied factors. We propose that the measurement of the length of the appendix may be used as an additional parameter for the postmortem evaluation of gestational age. Furthermore, its assessment may have potential as an ultrasonographic indicator of gestational age, particularly for the 2nd trimester.

Establishing normal ranges for fetal and neonatal small and large intestinal lengths: results from a prospective postmortem study

“…26 27 Whether IUGR impacts fetal intestinal length remains equivocal, 3 4 and in our analysis IUGR did not have any impact on intestinal length. Similar to prior literature, 4 maceration did not appear to have an impact on the growth of small intestinal lengths, and is in keeping with prior literature demonstrating that maceration does not alter all body measurements. 15 The presence of congenital anomalies did not alter the small intestinal length.…”

“…In keeping with other studies, no differences in intestine length were found between sexes, and hence we combined data for males and females to maximize the sample size. 4 22 23 …”

“… 15 The presence of congenital anomalies did not alter the small intestinal length. Though prior literature has demonstrated a reduction in length in Trisomy 21 fetuses, 4 we included a range of congenital anomalies, such as Turner syndrome and vermian hypoplasia, in addition to Trisomy 21. Combining the congenital anomalies may have attenuated the veritable impact of Trisomy 21 on fetal intestinal growth.…”

“…Marnerides et al established fetal intestinal length intervals in the second trimester and found considerable differences across weekly partitions. 4 To overcome these challenges, reference curves may be fitted to data and normal ranges can be obtained by using the functional form of the estimated curves at a given gestational age. We plan to pursue this approach in a subsequent study.…”

“…However, the RIs could still be applicable to postmortem populations with similar characteristics. 4 Further, to develop statistical models that account for the effects of age, sex, congenital anomalies, and other covariates, the Hoq et al ’s method could have been used to estimate RIs as a function of age. 30 The methods we used by Daly et al 21 were valid but did not exploit the linear relationship between age and intestinal length.…”