Maternal rest improves growth in small-for-gestational-age fetuses (<10th percentile).

BACKGROUND: Optimal management of fetuses diagnosed as small for gestational age based on an estimated fetal weight of <10th percentile represents a major clinical problem. The standard approach is to increase fetal surveillance with serial biometry and antepartum testing to assess fetal well-being and timing of delivery. Observational studies have indicated that maternal rest in the left lateral position improves maternal cardiac output and uterine blood flow. However, maternal bed rest has not been recommended based on the results of a randomized clinical trial that showed that maternal rest does not improve fetal growth in small-for-gestational-age fetuses. This study was conducted to revisit this question. OBJECTIVE: This study aimed to determine whether maternal bed rest was associated with an increase in the fetal biometric parameters that reflect growth after the diagnosis of a small-for-gestational-age fetus. STUDY DESIGN: A retrospective study was conducted on fetuses who were diagnosed as small for gestational age because of an estimated fetal weight of <10th percentile for gestational age. The mothers were asked to rest in the left lateral recumbent position. Fetal biometry was performed 2 weeks after the diagnosis. All fetuses before entry into the study had a previous ultrasound that demonstrated an estimated fetal weight of >10th percentile. To assess the response to bed rest, the change in fetal biometric parameters (estimated fetal weight, head circumference, abdominal circumference, and femur length) after the recommendation of bed rest was computed for 2 periods: (1) before the diagnosis of a weight of <10th percentile vs at the time of diagnosis of a weight of <10th percentile and (2) at the time of diagnosis of a weight of <10th percentile vs 2 weeks after maternal bed rest. For repeated measures, proportions were compared using the McNemar test, and percentile values were compared using the Kruskal-Wallis test. A P value of <.05 was considered significant. To describe changes in the estimated fetal weight without bed rest, 2 control groups in which the mothers were not placed on bed rest after the diagnosis of a small-for-gestational-age fetus were included. RESULTS: A total of 265 fetuses were observed before and after maternal bed rest. The following were observed in this study: (1) after 2 weeks of maternal rest, 199 of 265 fetuses (75%) had a fetal weight of >10th percentile; (2) the median fetal weight percentile increased from 6.8 (interquartile range, 4.4-8.4) to 18.0 (interquartile range, 9.5-29.5) after 2 weeks of bed rest; (3) similar trends were noted for the head circumference, abdominal circumference, and femur length. In the groups of patients who were not asked to be on bed rest, a reassignment to a weight of >10th percentile at a follow-up examination only occurred in 7 of 37 patients (19%) in the Texas-Michigan group and 13 of 111 patients (12%) in the Colorado group compared with the bed rest group (199/265 [75%]) (P<.001). CONCLUSION: Patients who were prescribed 2 weeks of bed rest after the diagnosis of a fetal weight of <10th percentile had an increase in weight of >10th percentile in 199 of 265 fetuses (75%). This increase in fetal weight was significantly higher than that in the 2 control groups in which bed rest was not prescribed. This observation suggests that bed rest improves fetal growth in a subset of patients.

Corpus Callosum Length and Cerebellar Vermian Height in Fetal Growth Restriction.

INTRODUCTION: Growth-restricted fetuses may have changes in their neuroanatomical structures that can be detected in prenatal imaging. We aim to compare corpus callosal length (CCL) and cerebellar vermian height (CVH) measurements between fetal growth restriction (FGR) and control fetuses and to correlate them with cerebral Doppler velocimetry in growth-restricted fetuses. METHODS: This was a prospective cohort of FGR after 20 weeks of gestation with ultrasound measurements of CCL and CVH. Control cohort was assembled from fetuses without FGR who had growth ultrasound after 20 weeks of gestation. We compared differences of CCL or CVH between FGR and controls. We also tested for the correlations of CCL and CVH with middle cerebral artery (MCA) pulsatility index (PI) and vertebral artery (VA) PI in the FGR group. CCL and CVH measurements were adjusted by head circumference (HC). RESULTS: CCL and CVH were obtained in 68 and 55 fetuses, respectively. CCL/HC was smaller in FGR fetuses when compared to control fetuses (difference = 0.03, 95% CI: [0.02, 0.04], p < 0.001). CVH/HC was larger in FGR fetuses compared to NG fetuses (difference = 0.1, 95% CI: [-0.01, 0.02], p = < 0.001). VA PI multiples of the median were inversely correlated with CVH/HC (rho = -0.53, p = 0.007), while CCL/HC was not correlated with VA PI. Neither CCL/HC nor CVH/HC was correlated with MCA PI. CONCLUSIONS: CCL/HC and CVH/HC measurements show differences in growth-restricted fetuses compared to a control cohort. We also found an inverse relationship between VA PI and CVH/HC. The potential use of neurosonography assessment in FGR assessment requires continued explorations.

Umbilical Venous Volume Flow in Late-Onset Fetal Growth Restriction.

OBJECTIVES: Umbilical vein flow (UVF) is reduced in fetal growth restriction (FGR). We compared absolute and size-adjusted UVF (estimated fetal weight [EFW] and abdominal circumference [AC]) and rates of abnormal UVF parameters (<10th percentile) among FGR fetuses meeting Delphi criteria (FGR-D) against small for gestational age (SGA) fetuses and appropriate for gestational age (AGA) controls. METHODS: Absolute UVF, UVF/EFW, and UVF/AC were compared between 73 FGR pregnancies (35 FGR-D, 38 SGA) and 108 AGA controls. Rates of abnormal UVF were compared to abnormal umbilical artery pulsatility index (UAPI). Independent samples t-tests, Mann-Whitney U, odds ratio (OR), chi-squared, and Fisher's exact tests were used as appropriate. RESULTS: Mean absolute UVF was significantly decreased in FGR-D compared to AGA (P = .0147), but not between SGA and AGA fetuses. The incidence of both abnormal absolute UVF and UVF/AC values (<10th centile) was higher among late-onset FGR fetuses versus AGA fetuses (UVF: OR 2.7, confidence interval [CI] 1.37-5.4; UVF/AC: OR 2.73, CI 1.37-5.4). UVF was more frequently abnormal than UAPI and in only two fetuses were both Doppler values abnormal. CONCLUSION: Absolute UVF is altered in late-onset FGR, and most pronounced among FGR-D. UVF may provide additional insight into fetal compromise in those affected by growth restriction.