Middle East Fertility Society Journal (2013) xxx, xxx–xxx
Middle East Fertility Society
Middle East Fertility Society Journal www.mefsjournal.org www.sciencedirect.com
ORIGINAL ARTICLE
Sonographic evaluation of fetal abdominal circumference and cerebroplacental Doppler indices for the prediction of fetal macrosomia in full term pregnant women. Cohort study Rana M.A. Abdella a b
a,*
, Shady A.M. Ahmed b, Magdy I. Moustafa
a
Department of Obstetrics and Gynecology, Obstetrics & Gynecology, Faculty of Medicine, Cairo University, Egypt Department of Obstetrics and Gynecology, Nag-Hammady General Hospital, Menia, Egypt
Received 12 March 2013; accepted 26 April 2013
KEYWORDS Fetal macrosomia; Cerebroplacental Doppler; LGA
Abstract Objectives: The aim of the study was to explore the relationship between cerebroplacental Doppler ratio and birth weight in cases of suspected fetal macrosomia. Methods: The pulsatility indices of the umbilical (UA-PI) and middle cerebral (MCA-PI) arteries, the cerebroplacental pulsatility index ratio (CPR) and the estimated fetal weight (EFW) were obtained in a cohort of 150 ultrasound-dated pregnancies at P 37 weeks’ gestation divided into two groups as follows; large for gestational age (LGA, n = 50) and average for gestational age (AGA, n = 100). Results: There is a significant difference between groups in abdominal circumference (AC), head circumference (HC), biparital diameter (BPD), estimated fetal weight (EFW) and actual fetal weight with a mean difference of 92.7 g in the LGA group and 84 g in the AGA group. MCA-RI and PI were significantly lower in the LGA group with no difference in UA-RI, PI and CPR-PI between both groups. Conclusions: CPR-PI could not differentiate between LGA and AGA. Ó 2013 Production and hosting by Elsevier B.V. on behalf of Middle East Fertility Society.
1. Introduction
* Corresponding author. Tel.: +20 1005605020. E-mail addresses:
[email protected] (R.M.A. Abdella). Peer review under responsibility of Middle East Fertility Society.
Production and hosting by Elsevier
Fetal macrosomia is defined as a birth weight of at least 4000 g or greater than the ninetieth percentile for gestational age after correcting for neonatal sex and ethnicity (1). Based on these definitions, macrosomia affects 1–10% of all pregnancies (23). Fetal macrosomia has many complications which can be associated with maternal and fetal morbidity and mortality (26). Shoulder dystocia, one of the worst obstetric emergencies,
1110-5690 Ó 2013 Production and hosting by Elsevier B.V. on behalf of Middle East Fertility Society. http://dx.doi.org/10.1016/j.mefs.2013.04.008 Please cite this article in press as: Abdella RMA et al. Sonographic evaluation of fetal abdominal circumference and cerebroplacental Doppler indices for the prediction of fetal macrosomia in full term pregnant women. Cohort study, Middle East Fertil Soc J (2013), http://dx.doi.org/10.1016/j.mefs.2013.04.008
2 occurs in 0.15–1.7% of vaginal deliveries. About half of shoulder dystocia happen to macrosomic infants (6,9). Despite not being rare, having an incidence of 10% or even more, no method has been sufficiently accurate in predicting birth weight (21). Many efforts have been dedicated to evaluate the accuracy with which clinical or ultrasonographic methods can predict birth weight. The abdominal circumference (AC) is the most important measurement in estimating fetal weight and only examination with high quality of the AC measurements must be accepted to calculate the EFW (23). There is a high probability that the baby is macrosomic even when the estimated fetal weight indicates a smaller size if the AC measurement is 2 or more standard deviations above the mean (23). The application of Doppler technique was used for the detection of complications of pregnancy, detection and characterization of certain fetal abnormalities, as well as assessment of the value of Doppler in the detection and management of the maternal diseases (16). Doppler ultrasound is used to assess fetal well being, particularly in antenatal surveillance of high risk pregnancies. It is the best noninvasive marker of placental function and it assesses the movement of blood in the blood vessels, which gives rise to a velocity waveform for analysis. The pathological basis for an abnormal umbilical artery waveform is obliteration of the small placental arteries within the placental vasculature, resulting in increased umbilical – placental resistance, as found in the intrauterine growth restricted fetuses. Several vascular changes have been found in the placentae of the diabetic mothers, such as the narrowing of the lumen and changes in the syncytiotrophoblast. However, the most characteristic change is the greater probability of fetal and placental vascular thrombosis (18). Doppler ultrasound allows the investigation of feto-placental circulation, thus providing a non invasive monitoring tool for assessing fetal well being. Umbilical artery Doppler reflects downstream placental vascular resistance, which is strongly correlated with intrauterine growth restriction and placental insufficiency. When umbilical arteries become abnormal, Doppler information from systemic vessels is required. Middle cerebral artery changes begin when the redistribution of the cardiac output reflects rising placental resistance, demonstrating ‘brain sparing’ when cerebro-vascular dilation occurs. The Doppler information is combined with biophysical profile (BPP) scoring to determine the need for and timing of intervention (12). Evaluation of the cerebral blood flow in the fetus has become an integrated part of the assessment of high-risk pregnancies. The middle cerebral artery (MCA) has been studied extensively, and its Doppler recordings are incorporated regularly into the management of fetuses at risk of developing placental compromise and fetal anemia (7). Combining the Doppler waveform analysis of the middle cerebral artery (MCA) with that of the umbilical artery (UA) by a common cerebroplacental ratio, i.e. the ratio of their pulsatility indices has been suggested as a useful clinical simplification (7). A cerebroplacental ratio reflects redistribution of the cardiac output to the cerebral circulation and has been shown to improve accuracy in predicting adverse outcome compared with MCA or UA Doppler alone (28). The aim of the study was to explore the relationship between cerebroplacental Doppler ratio and birth weight in cases of suspected fetal macrosomia
R.M.A. Abdella et al. 2. Patients and methods This is a prospective cohort study carried out from April 2010 to December 2010 at the Department of Obstetrics and Gynecology, Faculty of Medicine; Cairo University and was approved by the institutional review board. Consecutive parturient women during the study period with well-dated term pregnancies P37 gestational weeks were admitted and recruited after giving written consent. The cohort of enrolled women was divided into two groups according to the fetal birth weight (FBW) i.e. >4 kg. Group I (LGA; n = 50) with large weight for gestational age babies and Group II (AGA; n = 100) with average weight for gestational age. The inclusion criteria included a singleton pregnancy with gestational age correctly dated by either a first-trimester measurement of crown-rump length or a second-trimester (before 20 weeks) ultrasound examination with clinically suspected fetal macrosomia. Measurement of the symphysis – fundal height together with Leopold’s maneuvers was done for clinical estimation. Exclusion criteria included those with unreliable dates, twin pregnancy, gross fetal abnormalities, and pregestational diabetes or hypertensive disorders with pregnancy. All ultrasound measurements were performed by using VOLUSON E6, VOLUSON 730, MINDRAY DC3, and ACCUVIX X 8, ACCUVIX V20 ultrasound machine equipped with a 3.5-MHz convex transabdominal probe. Fetal biometry and abdominal circumference were measured and weight calculated using the Hadlock formula16. Fetal umbilical artery (UA) and middle cerebral artery (MCA) flow velocity waveforms were assessed using color and pulse wave Doppler studies on a free loop of the umbilical cord and at the origin of the circle of Willis, respectively, to obtain the pulsatility index (PI) and resistance index (RI). The high-pass filter was set at the minimum and the pulse repetition frequency was 2.5 kHz. A minimum of three consecutive waveforms of similar configuration were used for Doppler assessment. Ultrasound examination was done by a single operator to avoid interobserver variability. All deliveries occurred within 24 h after the ultrasound examination. The obstetric outcomes were recorded, including the incidence of Cesarean section and instrumental delivery. Maternal complications such as postpartum hemorrhage, cervical and vaginal laceration and fetal complications in terms of shoulder dystochia, cephalhaematoma, and hypoglycemia were reported. The incidence of deliveries requiring intervention for fetal distress and admission into a neonatal intensive care unit (NICU) was also recorded. Following delivery the neonatal outcome was recorded in terms of Apgar scoring at 5 min, neonatal birth weight and the need for NICU. Neonatal birth weight was measured by using a spring-operated scale, with a sensitivity of ±50 g. Data were statistically described in terms of mean ± standard deviation (±SD), frequencies (number of cases) and percentages when appropriate. Comparison of quantitative variables between macrocosmic and non macrosomic groups was done using Student’s t test for independent samples. For comparing categorical data, Chi square (v2) test was performed. Exact test was used instead when the expected frequency is >5. Accuracy was represented using the terms sensitivity and specificity. Receiver operator characteristic (ROC) analysis was used to determine the optimum cut off value for the studied diagnostic markers. A probability value
Please cite this article in press as: Abdella RMA et al. Sonographic evaluation of fetal abdominal circumference and cerebroplacental Doppler indices for the prediction of fetal macrosomia in full term pregnant women. Cohort study, Middle East Fertil Soc J (2013), http://dx.doi.org/10.1016/j.mefs.2013.04.008
Sonographic evaluation of fetal abdominal circumference and cerebroplacental Doppler indices (P value) less than 0.05 was considered statistically significant. All statistical calculations were done using computer programs Microsoft Excel 2007 (Microsoft Corporation, NY, and USA) and SPSS (Statistical Package for the Social Science; SPSS Inc., Chicago, IL, USA) version 15 for Microsoft Windows. 3. Results 150 pregnant women consented to participate in the study. The cohort of enrolled women was divided into two groups according to the fetal birth weight (FBW) i.e. >4 kg. Group I (LGA; n = 50) with large weight for gestational age babies and Group II (AGA; n = 100) with average weight for gestational age. Table 1 shows the demographic characteristics in both groups; the median age of women was 33.0 years for women with LGA and 26.5 years in women with AGA. BMI was significantly higher in the LGA than AGA (34.6 vs. 28.2, P < 0.05). The mean gestational age at the time of labor was around 39 gestational weeks and the median age was significantly higher in the LGA group than the AGA (4082 vs. 3177 g, P < 0.05). Six women had controlled gestational diabetes on diet in the LGA group. Table 2 shows the means of 2D ultrasound biometry measurements and Doppler indices UA-PI and MCA-PI in the two birth weight groups. There is a significant difference between groups in abdominal circumference (AC), head circumference (HC), Biparital diameter (BPD), estimated fetal weight (EFW) and actual fetal weight with a mean difference
Table 1
4. Discussion The intrapartum management of macrosomic fetuses is still a challenge for the obstetrician, due to potentially unpreventable complications both for the mother and especially for the newborn during labor (22). The incidence of birth weights greater than 4000 g is in the range of 5–8%, and the incidence in infants weighing over 4500 g is reported to be 1.0–1.5%. Earlier reports have suggested that factors associated with oversized fetuses include maternal weight, prior delivery of a large infant, and excessive maternal weight gain during pregnancy (11).
Demographic data among the studied population.
Maternal age at inclusion (years) Parity Nullparous 1–3 P4 Gestational diabetes Gestational age at delivery (weeks) Body mass index (kg/m2) Actual fetal birth weight (gm)
Table 2
of 92.7 g in the LGA group and 84 g in the AGA group. MCA-RI and PI were significantly lower in the LGA group with no difference in UA-RI, PI and CPR-PI between both groups. Table 3 shows the prediction of fetal macrosomia at different cut-offs, identified by ultrasound biometry and Doppler indices. At each cut-off, the optimal measurements of different parameters were determined using ROC curve with the highest sensitivity and specificity (Fig. 1). Table 4 illustrates the obstetric and neonatal outcomes in both groups; there was an evidence of statistically significant difference in terms of prolonged labor, instrumental delivery and cesarean section in favor of large for gestational age group (LGA) (P < 0.05). On the other hand, there was no evidence of statistically significant difference between both groups as regards the rate of neonatal admission to NICU, maternal and neonatal complications.
LGA (n = 50)
AGA (n = 100)
P
33 (23–41) 2.0 ± 1.89 15 (30%) 32 (64%) 3.0 (6%) 6.0 (12%) 39.5 (37–42) 34.6 (29.4–45.6) 4082 ± 650
26.5 (18–37) 2.0 ± 1.82 38 (38%) 53 (53%) 9.0 (9%) 0.0 39 (37–41) 28.2 (23.8–41.5) 3177 ± 450
0.03 0.42
0.1 0.02 0.000
Intrapartum ultrasound biometry and Doppler measurements. LGA (n = 50) M ± SD
Abdominal circumference (AC) Head circumference (HC) Biparital diameter (BPD) Femur length (FL) Estimated fetal weight (EFW) Actual fetal weight (AFW) Apgar score at 5 min Doppler indices MCA-RI MCA-PI UA-RI UA-PI CPR-PI
371.25 ± 13.6 339.3 ± 10.7 93.9 ± 5.98 75 ± 6.1 3989.3 ± 231 4082 ± 142 8.6 ± 0.9 0.6888 ± 0.12 1.3022 ± 0.36 0.5840 ± 0.07 0.9090 ± 0.18 1.23425 ± 0.3
AGA (n = 100) M ± SD 330.5 ± 17 330 ± 11 91.7 ± 3.42 70.4 ± 7.2 3093 ± 349 3177 ± 358.5 8.7 ± 0.9 0.7390 ± 0.08 1.4618 ± 0.33 0.5972 ± 0.06 1.8076 ± 6.34 1.27640 ± 0.2
P
