Two-Dimensional Sonographic Placental Measurements in the Prediction of Small for Gestational Age Infants
Amira Elzanaty Saad Ibraim;
Abstract
Small-for-gestational age (SGA) fetuses are at increased risk of perinatal death and handicap, but these risks are substantially reduced in cases of SGA identified antenatally, compared to those detected after birth (Lindqvist and Molin, 2005). Studies show that approximately one-third of growth restricted fetuses remain undetected before delivery (van Wassenaer, 2005; Pallotto and Kilbride, 2006).
Early estimation of patient-specific risks for SGA could potentially improve pregnancy outcome by shifting antenatal care from a series of routine visits to a more individualized approach both in terms of the schedule and content of such visits. There is also evidence that the prophylactic use of low-dose aspirin started in early pregnancy can potentially halve the incidence of fetal growth restriction (Bujold et al., 2010).
Histological studies reported that in pregnancies complicated by preeclampsia and SGA without preeclampsia there is evidence of impaired placentation characterized by inadequate trophoblastic invasion of the maternal spiral arteries (Pijnenborg et al., 2006). However, the magnitude of such impairment with SGA is considerably less than in preeclampsia (Karagiannis et al., 2010).
Early reliable predictors of placental dysfunction remain lacking in obstetric care. In reality, it is likely that no single test will achieve sufficient accuracy to be used in clinical practice as a stand-alone test in the prediction of pregnancy complications. Early identification of a pregnancy at risk of impaired fetal growth and an adverse outcome may allow for increased fetal surveillance to be implemented with the goal of preventing an adverse outcome. In addition, future medical advances may yield effective therapeutic options that, if used early in appropriately identified high-risk pregnancies, may decrease the incidence of adverse outcome (Schwartz et al., 2011).
Several parameters were used to assess fetal growth in order to quantify intrauterine environmental adequacy and fetal well-being (Wolf et al., 1989; Hafner et al., 1998). Normal placental function and structure is a necessary factor for the formation of a healthy fetus and consequently normal birth weight (Habib, 2002).
The rate of placental growth appears to be an important determinant of birth weight, with the rate between 17 and 20 weeks gestation being a predictor of fetal abdominal and head circumference, femoral length and biparietal diameter; weaker associations are observed for placental growth earlier in pregnancy (Holroyd et al., 2012).
Several aspects of placental growth including volume, weight, and plate area were investigated in different researches in order to find their correlation with fetal anthropometry (Azpurua et al., 2010). Clapp and colleagues (1995) evaluated placental growth of forty singleton pregnant women and they showed a significant correlation (r>0.79) between second-trimester placental growth rate and birth weight. In study of Kinare and associates (2000), mid-pregnancy placental volume was related to birth weight. Correlation of placental thickness with gestational age and fetal growth was also reported in a research by Karthikeyan and colleagues (2012).
Although the placenta plays a central role in the pathophysiology of many adverse pregnancy outcomes, currently no direct measures of placental biometry are used in clinical practice (Schwartz et al., 2012).
The aim of this study is to investigate the potential utility of 2D placental measurements in the early prediction of SGA and to determine whether these placental measurements could be combined with fetal biometric lags to improve the early prediction of SGA.
This study is a prospective cohort study which was carried out at Ain shams university maternity hospital ultrasound unit. The study included 200 pregnant women at 18-24 weeks gestation with high risk for small for gestational age fetus presented for antenatal care.
In this study, maternal risk factors for small for gestational age babies included: cardiac disease in 20 patients (10%), hypertension in 60 patients (30%), diabetes mellitus in 35 patients (17.5%), anemia in 20 patients (10%), liver disease in 15 patients (7.5%), systemic lupus erythromatosis in 9 patients (4.5%), anti phospholipid syndrome in 19 patients (9.5%) and history of previous small for gestational age baby in 22 patients (11%).
The risk for SGA has been shown to be inversely related to maternal weight and height, and increased with maternal age and in cigarette smokers, in women of African and Asian racial origin, in those with a medical history of chronic hypertension, in women with a previous SGA neonate and in those who had assisted conception (Poon et al., 2011).
In the present study, 170 patients (85%) gave birth to babies with birth weight more than 10th percentile while the other 30 patients (15%) gave birth to babies below 10th percentile. Then patients were divided into 2 groups according to fetal birth weight using 10th percentile as a cutoff value to compare between groups.
As regards general characteristics, the >10th percentile group showed a significant difference in maternal age, while the difference between both groups in BMI and gestational age at delivery was non significant.
In the current study, the mean of gestational age calculated from the last menstrual period at time of ultrasonography was 21.2 versus 20.4 weeks in the above 10th versus below 10th groups respectively which was not significant.
As regards ultrasound scan, gestational age estimated by biparietal diameter (BPD), femur length (FL) and head circumference (HC) was significantly less in the below 10th group as compared to above 10th group while the difference in estimated gestational age using abdominal circumference (AC) was comparable between both groups.
Early estimation of patient-specific risks for SGA could potentially improve pregnancy outcome by shifting antenatal care from a series of routine visits to a more individualized approach both in terms of the schedule and content of such visits. There is also evidence that the prophylactic use of low-dose aspirin started in early pregnancy can potentially halve the incidence of fetal growth restriction (Bujold et al., 2010).
Histological studies reported that in pregnancies complicated by preeclampsia and SGA without preeclampsia there is evidence of impaired placentation characterized by inadequate trophoblastic invasion of the maternal spiral arteries (Pijnenborg et al., 2006). However, the magnitude of such impairment with SGA is considerably less than in preeclampsia (Karagiannis et al., 2010).
Early reliable predictors of placental dysfunction remain lacking in obstetric care. In reality, it is likely that no single test will achieve sufficient accuracy to be used in clinical practice as a stand-alone test in the prediction of pregnancy complications. Early identification of a pregnancy at risk of impaired fetal growth and an adverse outcome may allow for increased fetal surveillance to be implemented with the goal of preventing an adverse outcome. In addition, future medical advances may yield effective therapeutic options that, if used early in appropriately identified high-risk pregnancies, may decrease the incidence of adverse outcome (Schwartz et al., 2011).
Several parameters were used to assess fetal growth in order to quantify intrauterine environmental adequacy and fetal well-being (Wolf et al., 1989; Hafner et al., 1998). Normal placental function and structure is a necessary factor for the formation of a healthy fetus and consequently normal birth weight (Habib, 2002).
The rate of placental growth appears to be an important determinant of birth weight, with the rate between 17 and 20 weeks gestation being a predictor of fetal abdominal and head circumference, femoral length and biparietal diameter; weaker associations are observed for placental growth earlier in pregnancy (Holroyd et al., 2012).
Several aspects of placental growth including volume, weight, and plate area were investigated in different researches in order to find their correlation with fetal anthropometry (Azpurua et al., 2010). Clapp and colleagues (1995) evaluated placental growth of forty singleton pregnant women and they showed a significant correlation (r>0.79) between second-trimester placental growth rate and birth weight. In study of Kinare and associates (2000), mid-pregnancy placental volume was related to birth weight. Correlation of placental thickness with gestational age and fetal growth was also reported in a research by Karthikeyan and colleagues (2012).
Although the placenta plays a central role in the pathophysiology of many adverse pregnancy outcomes, currently no direct measures of placental biometry are used in clinical practice (Schwartz et al., 2012).
The aim of this study is to investigate the potential utility of 2D placental measurements in the early prediction of SGA and to determine whether these placental measurements could be combined with fetal biometric lags to improve the early prediction of SGA.
This study is a prospective cohort study which was carried out at Ain shams university maternity hospital ultrasound unit. The study included 200 pregnant women at 18-24 weeks gestation with high risk for small for gestational age fetus presented for antenatal care.
In this study, maternal risk factors for small for gestational age babies included: cardiac disease in 20 patients (10%), hypertension in 60 patients (30%), diabetes mellitus in 35 patients (17.5%), anemia in 20 patients (10%), liver disease in 15 patients (7.5%), systemic lupus erythromatosis in 9 patients (4.5%), anti phospholipid syndrome in 19 patients (9.5%) and history of previous small for gestational age baby in 22 patients (11%).
The risk for SGA has been shown to be inversely related to maternal weight and height, and increased with maternal age and in cigarette smokers, in women of African and Asian racial origin, in those with a medical history of chronic hypertension, in women with a previous SGA neonate and in those who had assisted conception (Poon et al., 2011).
In the present study, 170 patients (85%) gave birth to babies with birth weight more than 10th percentile while the other 30 patients (15%) gave birth to babies below 10th percentile. Then patients were divided into 2 groups according to fetal birth weight using 10th percentile as a cutoff value to compare between groups.
As regards general characteristics, the >10th percentile group showed a significant difference in maternal age, while the difference between both groups in BMI and gestational age at delivery was non significant.
In the current study, the mean of gestational age calculated from the last menstrual period at time of ultrasonography was 21.2 versus 20.4 weeks in the above 10th versus below 10th groups respectively which was not significant.
As regards ultrasound scan, gestational age estimated by biparietal diameter (BPD), femur length (FL) and head circumference (HC) was significantly less in the below 10th group as compared to above 10th group while the difference in estimated gestational age using abdominal circumference (AC) was comparable between both groups.
Other data
| Title | Two-Dimensional Sonographic Placental Measurements in the Prediction of Small for Gestational Age Infants | Other Titles | قياسات المشيمة بواسطة الموجات الصوتية ثنائية الأبعاد للتنبؤ بالأجنة صغيرة الحجم بالنسبة لفترة الحمل رسالة | Authors | Amira Elzanaty Saad Ibraim | Issue Date | 2015 |
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