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Prenatal and postnatal growth: An ultrasound and clinical investigation
Address for Correspondence: Dr. Shahista Parveen, Department of Orthodontics and Dentofacial Orthopaedics, Yenepoya Dental College, Mangalore, Karnataka, India. E-mail: drshahistaparveen@yahoo.com
This article was originally published by Wolters Kluwer and was migrated to Scientific Scholar after the change of Publisher.
How to cite this article: Parveen S, Mascarenhas R, Husain A, Acharya D. Prenatal and postnatal growth: An ultrasound and clinical investigation. APOS Trends Orthod 2016;6:147-53.
Abstract
Background
Understanding facial development requires sound knowledge of growth at different stages. Although studies in the past have established the relationship between prenatal and postnatal growth, little research has been done using noninvasive ultrasound. The purpose of this study is to evaluate correlation between prenatal and postnatal growths using ultrasound as a fetal growth assessment tool.
Study
Settings: It is a hospital-based study where prenatal growth is measured at different intervals of gestational period and compared with the growth at birth.
Materials
and Methods: Ten subjects with normal pregnancy were studied using ultrasound. Cephalocaudal growth gradient, body proportions of the fetus were assessed and compared at different stages. Growth was also evaluated at birth and compared with the predicted growth.
Results
The growth rate of estimated fetal weight is at maximum between the 28th and 32nd week of the fetal life (P ≤ 0.001). The growth rate of head circumference, occipitofrontal diameter, and femur length is maximum between the 20th and 28th week of the fetal life (P < 0.001). Cephalocaudal growth gradient decreases with increased age of the fetus.
Conclusions
Prenatal growth is correlated with postnatal growth. Ultrasound can be used as a tool for the measurement and prediction of prenatal and postnatal growths.
Keywords
Body proportions
cephalocaudal growth
postnatal growth
prenatal growth
ultrasound
INTRODUCTION
Human growth is an outcome of complex interactions between genes and the environment. A human being undergoes a synchronized balance of growth and development of body proportions throughout the prenatal and postnatal phases. Growth commences immediately after conception and can be divided into prenatal and postnatal growths.[1] In studies of growth and development, the concept of pattern is important and refers to the changes in proportional relationships over time.[2] A normal growth pattern follows a cephalocaudal growth gradient which means that there is an axis of increased growth extending from the head toward the feet.[2] The “law of cephalocaudal differential growth” states that development begins at the cephalic end and progresses toward the tail.[3] A cephalocaudal pattern of growth is also documented in orthodontic literature, which changes in proportion with time.[1,2,4] After birth, the proportion of the head to the body is greater in an infant and gradually reduces toward adulthood which is also applied to prenatal growth. The growth gradient proportion has been reported in textbooks without any evidence-based study.
The earliest written records of human growth are from the Mesopotamian civilization.[5] Leonardo da Vinci also studied human growth and development from conception onward. He undertook human dissection of the placenta, fetus, and stillborn. He used his scientific study of human growth to produce drawings that correctly rendered child and adult body proportions. In 1651, William Harvey showed that during the prenatal development, there is a series of embryological stages that are distinct in appearance.[5] Growth research began with the invention of the anthropometer by Johann in 1654. The discovery of X-rays and its subsequent use in medical sciences helped in the study of skeletal development. Introduced in 1960, ultrasound is the most widely used diagnostic modality today.[6] It is the most commonly used tool to visualize different fetal anatomical landmarks and to follow growth during pregnancy.[6] Recent technological advances in ultrasound imaging which include improved spatial and contrast resolution have rekindled interest in sonographic imaging in other fields as well. Ultrasound in orthodontics has been used as diagnostic tool for the dynamic functional analysis of the tongue[7-10] and temporomandibular joint dysfunction[11] and for the measurement of muscle thickness.[12-16] Reference ranges for fetal ultrasound biometry have been reported by a number of investigators.[17-26] Many formulae and parameters have been correlated with fetal weight.[27-29] Several studies have investigated the validity of ultrasound in estimation of fetal weight by comparing with birth weight and concluded that it is a reliable tool for growth evaluation.[30-32]
Orthodontics includes the study of the growth of the face which cannot be studied without understanding body growth. In the past, various methods such as a bimetric test, vital staining, radioisotopes, implants, natural markers, and anthropometric measurements have been used to measure growth.[2] Although ultrasound is used in orthodontics, it has not been used to evaluate growth. The aim of this study is to evaluate overall body proportion and cephalocaudal growth gradient at different stages using ultrasound.
MATERIALS AND METHODS
This study included subjects reporting to the department of obstetrics and gynecology of our university hospital for routine antenatal checkups. This study was approved by our university’s ethics committee. The purpose of the study and protocol was explained to the patients and informed consent was obtained before the study. Normal singleton pregnancy with no maternal medical diseases at the time of gestation was included as the subjects. A fetus with congenital anomalies, twin pregnancy, oligohydramnios, and intrauterine growth restriction was excluded from the study. Ten subjects were followed up for the study. All the subjects were examined by a single examiner. Transabdominal ultrasound was performed using a GE logic P3 ultrasound machine with 4 MHz convex probe. The imaging system provided conventional two-dimensional ultrasonographic images, generated within seconds. Images were captured and stored. Both established and new parameters were used for the study. Established parameters included in the study were (1) head circumference (HC), (2) biparietal diameter (BPD), (3) occipitofrontal diameter (OFD), (4) femur length (FL), (5) abdomen circumference (AC), and (6) estimated fetal weight (EFW). New parameters used to assess cephalocaudal growth and overall body proportions were defined and standardized. New parameters added in the study were (1) head to chin (H-C), (2) neck to hip (N-H), (3) hip to knee (H-K), (4) knee to foot (K-F), (5) shoulder to elbow, and (6) elbow to wrist. Anthropometric measurements of neonates were evaluated within 24 h of birth obtained by an infantometer, calibrated electronic weighing scale, nonstretchable tape, and with a flexible scale.
Biparietal diameter
This is the distance between the parietal eminences [Figure 1a] which was measured from the outer edge of the nearerparietal bone to the inner edge of the more distant parietal bone.[6,23,26] It can be measured through any plane of a section through a 360° arc that traverses the third ventricle and thalamus. With OFD, it is used to calculate the cephalic index (CI). BPD was compared with maximum skull width (MSW) at birth [Figure 1b].
- (a) Biparietal diameter of the fetus. (b) Maximum skull width at birth
Occipitofrontal diameter
OFD was measured in a plane perpendicular to BPD between the anterior edge of the frontal bone and the outer border of the occiput[6,23,26] [Figure 2a]. OFD was correlated with maximum skull length (MSL) at birth [Figure 2b].
- (a) Occipitofrontal diameter of fetus. (b) Maximum skull length at birth
Cephalic index
The CI of a fetus was calculated using OFD and BPD. CI = BPD/OFD × 100. The CI of neonates was calculated using the formula = MSW (eu-eu) × 100/MSL (g-op).[6,23,26]
Head circumference
To measure HC [Figure 3a], the correct plane of a section is the third ventricle and thalamus in the central portion of the brain.[6,23,26] Here, the cursor is placed between the outer edge of one calvarial wall and the inner edge of the other calvarial wall. HC was estimated from the measurement of the OFD and BPD using a formula for an ellipse. The HC of the fetus was compared with the HC of the neonate [Figure 3b].
- (a) Head circumference of fetus. (b) Head circumference at birth
Femur length
This is the linear distance between the ossifi ed portions of the femur [Figure 4].[6,24,26] To measure this parameter, a transducer is properly aligned to the long axis of diaphysis of the bone. Then, the cursor is placed properly at the correct endpoints of the bone. A normal body ratio can be correlated using FL.
- Femur length
Abdomen circumference
AC can be measured ultrasonographically at the position where the transverse diameter of the liver is largest and both the right and left portal veins are continuous with one another.[6,24,26] After this plane of a section is frozen in the skin, the ellipse is fit into the skin edge. If the ultrasound machine is not equipped with a computer-generated ellipse measurement capability, AC can be calculated with transverse and anteroposterior diameters of the abdomen and the formula is (D1 + D2)/× 1.57 [Figure 5].[6]
- Abdomen circumference
Estimated fetal weight
Many formulae and nomograms have been developed for the estimation of fetal weight.[6,27-30] Among them, the Shepard formula, which includes BPD and AC, and the Hadlock formula using BPD, FL, and AC are widely accepted and commonly used for the estimation of fetal weight.[30] Most ultrasound equipment comes with computer packages that will automatically calculate the EFW. The predicted growth at birth was compared with the actual birth weight [Figure 6] after EFW was adjusted adding average growth for each day between the last scan and delivery. The deviation between predicted birth weight and actual birth weight was considered as the estimating error, which was calculated on the basis of the following formula:[30-32]
- Birth weight
Absolute percentage error = (Predicted birth weight − Birth weight)/Birth weight × 100
Head to chin
H-C is the linear distance between the head and the chin [Figure 7a and b]. To measure this, one end of the cursor was placed at the vertex (the highest point on the head) and the other end on the inferior portion of the chin. A midcoronal plane was taken for the measurement.
- (a) Head to chin measurement of fetus. (b) Head to chin at birth
Neck to hip
N-H is the linear distance measured between the first cervical vertebra and the last vertebra [Figure 8a and b]. Since the vertebral column is not straight, curvilinear measurements were taken in segments [Figure 8a]. As the gestational age increases, an N-H measurement recorded at two planes. The measurements were then added together.
- (a) Neck to hip measurement of fetus. (b) Neck to hip at birth
Hip to knee
H-K was measured by placing one end of the cursor on the highest point of the hip bone and other end of the cursor on the lowest point of the femur/joint line [Figure 9a and b].
- (a) Hip to knee measurement of fetus. (b) Hip to knee at birth
Knee to foot
K-F was measured from the lowest portion of the knee/joint line to the inferior portion of the heel [Figure 10a and b].
- (a) Knee to foot measurement of fetus. (b) Knee to foot at birth
Shoulder to elbow
S-E was measured by placing one end of the cursor on acromion process of the scapula and the other end was placed on the lowest portion of the humerus/joint line [Figure 11a and b].
- (a) Shoulder to elbow measurement of fetus. (b) Shoulder to elbow at birth
Elbow to wrist
E-W is the linear distance from elbow/joint line to the distal portion of the radial ulnar joint [Figure 12a and b].
- (a) Elbow to wrist of the fetus. (b) Elbow to wrist at birth
Cephalocaudal growth gradient was calculated from the ratio of H-C and neck to foot which is added sum of N-H, H-K, and K-F.
All the above-mentioned parameters were measured at the 20th, 28th, 32nd, 36th weeks of pregnancy and also at birth. New parameters were derived for measuring cephalocaudal growth.[1-4] The per day growth rate of the fetus was calculated using the formula: Difference in the growth between the two intervals of scan/number of days between the intervals. Body proportions were measured and compared. A cephalocaudal growth gradient was calculated and compared at different intervals. Growth predicted and postnatal measurements were compared using the formula = (predicted– observed)/observed × 100.
Statistical analysis
Data were recorded at different intervals of the fetal period and at birth. Microsoft Excel was used to compile the data. Mean and standard deviations of each parameter were calculated. SPSS version 16 (SPSS, Chicago, Illinois, USA) was used for statistical analysis. Data were analyzed using repeated measure ANOVA. Based on the sphericity, Greenhouse-Geisser comparison test was used within the subjects.
RESULTS
Measurements were taken at different intervals of pregnancy and also at birth are listed in Table 1. The per day growth of the fetus is calculated and presented in Table 2. The growth rate of EFW was at maximum between the 28th and 32nd week of the fetal life (28.9700 ± 0.885816) and remained almost the same (28.58600 ± 4.018579) [Table 2] (P < 0.001). The growth rate of OFD, HC, and FL was at maximum between the 20th and 28th week of the fetal life (P < 0.001) and also the peak growth of other parameters was found maximum between the 20th and 28th week of the fetal life. (P > 0.01) [Table 2].
| 20th week | 28th week | 32nd week | 36th week | At birth | ||
|---|---|---|---|---|---|---|
| EFW (g) | 455.5 | 1296 | 2497 | 3240 | 3138 | |
| BPD (mm) | 52.5 | 72.5 | 85.33 | 93.4 | 93.66 | |
| OFD (mm) | 67.5 | 94 | 107.833 | 114.5 | 114 | |
| Head circumference (mm) | 192.6 | 267 | 313.5 | 336.2 | 347.50 | |
| Abdomen circumference (mm) | 164.5 | 241.16 | 301.66 | 334 | 340 | |
| Femur length (mm) | 37.16 | 54.83 | 66.83 | 74.5 | ||
| Head to chin (mm) | 76.83 | 99.5 | 117.33 | 125.75 | 129.83 | |
| Neck to hip (mm) | 110.83 | 138.8 | 165.66 | 167.66 | 210 | |
| Hip to knee (mm) | 55.66 | 81.6 | 96.5 | 102 | 113.33 | |
| Knee to foot (mm) | 53.16 | 75.5 | 85.16 | 92 | 107 | |
| Shoulder to elbow (mm) | 54.5 | 70.16 | 80 | 87 | 92.9 | |
| Elbow to wrist (mm) | 47.166 | 62.33 | 66.83 | 75.2 | 79.16 | |
ESW – Estimated fetal weight; BPD – Biparietal diameter; OFD – Occipitofrontal diameter
| Mean±SD | n | P | ||||
|---|---|---|---|---|---|---|
| T1 | T2 | T3 | ||||
| EFW* | 17.88160±4.194788 | 28.9700±0.885816 | 28.58600±4.018579 | 10 | 0.001 | |
| BPD | 0.41232±0.076823 | 0.32960±0.065363 | 0.27400±0.063608 | 10 | 0.075 | |
| OFD* | 0.53920±0.056575 | 0.36584±0.081613 | 0.15920±0.032453 | 10 | <0.001 | |
| Head circumference* | 1.55380±0.167028 | 1.11260±0.148485 | 0.72404±0.159326 | 10 | <0.001 | |
| Abdomen circumference | 1.70460±0.409269 | 1.42830±0.145840 | 1.18000±0.201866 | 10 | 0.087 | |
| Femur length* | 0.36648±0.051861 | 0.29074±0.024727 | 0.26590±0.26590 | 10 | 0.027 | |
| Head to chin | 0.48329±0.183050 | 0.44600±0.142574 | 0.29925±0.249088 | 10 | 0.425 | |
| Neck to hip | 0.60325±0.214564 | 0.99700±0.783584 | 0.28738±0.134336 | 10 | 0.223 | |
| Hip to knee | 0.55533±0.299308 | 0.34733±0.172862 | 0.25400±0.139528 | 10 | 0.326 | |
| Knee to foot | 0.44275±0.091014 | 0.21525±0.098642 | 0.22850±0.181779 | 10 | 0.139 | |
| Shoulder to elbow | 0.33200±0.130652 | 0.31320±0.143648 | 0.20140±0.157089 | 10 | 0.434 | |
| Elbow to wrist | 0.26800±0.196022 | 0.22940±0.231710 | 0.27700±0.115789 | 10 | 0.923 | |
Cephalocaudal growth gradient decreased from 20th week (0.3434) to 28th week (0.3393) and at birth (0.3206) [Table 3]. The CI varied from 77% to 81% [Table 4].
| Mean±SD | n | P | |
|---|---|---|---|
| 20 weeks | 0.343400±0.0206833 | 10 | 0.753 |
| 28 weeks | 0.339300±0.0240094 | 10 | |
| Birth | 0.320660±0.0574562 | 10 |
SD – Standard deviation
| Cephalic index (weeks) | Mean±SD | n |
|---|---|---|
| 20 | 77.2990±3.41867 | 10 |
| 28 | 77.6300±2.32064 | 10 |
| 32 | 78.7060±2.47602 | 10 |
| 36 | 80.8950±1.25245 | 10 |
| At birth | 81.7420±2.06480 | 10 |
SD – Standard deviation
The growth of all the parameters at birth was predicted and compared with the actual growth. The percentage error between two is calculated and listed in Table 5. BPD was comparable with MSW at birth with an error of 1.554%. OFD was comparable with the MSL at birth with an error of 0.675%. HC of the fetus can be correlated with the postnatal HC with an error of −2.204%. H-C, a new parameter used in this study, can be compared with H-C measurement at birth with the percentage error of 0.11%.
| Predicted measurement at birth | Actual measurement at birth | Percentage of error | |
|---|---|---|---|
| Birth weight | 3425.77 | 3138 | 9.145 |
| Maximum skull width | 95.116 | 93.66 | 1.554 |
| Maximum skull length | 114.77 | 114 | 0.675 |
| Head circumference | 339.84 | 347.50 | −2.204 |
| Abdomen circumference | 343.07 | 340 | 0.905 |
| Head to chin | 129.97 | 129.83 | 0.11 |
| Neck to hip | 171.88 | 210 | −18.152 |
| Hip to knee | 103.6 | 113.33 | −8.58 |
| Knee to foot | 93.07 | 107 | −12.63 |
| Shoulder to elbow | 88.746 | 92.9 | −4.47 |
| Elbow to wrist | 73.360 | 79.16 | −3.53 |
DISCUSSION
The assessment of growth is important for treatment planning and timing of orthodontic therapy. Although many studies have been conducted in the past to understand the relationship between prenatal and postnatal growth, no study has been conducted to date using ultrasound in orthodontics. Six established parameters and six new parameters were used to evaluate prenatal growth. These parameters were used as indicators and predictors to evaluate growth [Table 2 and 3].
Established parameters
The per day growth of the fetus was evaluated using all the parameters. The growth rate of EFW, OFD, HC, and FL was statistically significant (P < 0.001). The growth rate of EFW was maximum between the 28th and 32nd week and then remained almost the same [Table 2], and when compared to the birth weight the mean percentage error was 9.145% [Table 5], which was in the same range as reported by Pinette.[30] HC and OFD are important predictors of craniofacial growth, and growth rate was found to be maximum between the 20th and 28th week of the fetal life. Predicted and postnatal measurements of HC and OFD were found to be accurate [Table 5]. FL is the ossified portion of a femur and one of the indicators of growth. The growth of FL was maximum between the 20th and 28th week of the fetal life. A similar comparison with FL was not possible because the FL is a hard-tissue parameter, could not be measured after birth. When compared to birth measurement, BPD and AC were found to be accurate and reliable [Table 5].
New parameters
All the new parameters also showed peak growth between the 20th and 28th week of the fetal life [Table 2]. H-C, a new parameter introduced in this study, was found to be reliable and accurate. The percentage error between the predicted and actual growth of H-C was found to be 0.11% [Table 5]. The cephalocaudal growth gradient was decreased from the 20th weeks to birth [Table 3]. Cephalocaudal growth gradient at the 32nd and 36th week was not calculated because of limitations in measuring the N-H parameter. The CI ranges from 77% to 82% indicating mesocephalic head types [Table 4].
In general, peak growth of fetus was between the 20th and 28th week of the fetal life which indicates that maximum growth and development of the fetus takes place during this period. Since very few longitudinal studies have been conducted in the past, serial values with repeated ultrasounds will help in studying prenatal growth and development. As multiple parameters are required to assess prenatal growth, the newly introduced parameters can also be used to measure growth. The study of craniofacial complex, which includes maxilla and mandible, is important to orthodontists and can be studied using scheduled ultrasound examinations. Individual linear and angular measurement of facial bones can be studied and followed up using ultrasound. Further studies are required to validate newly introduced parameters.
CONCLUSION
Cephalocaudal growth decreases with age. H-C, a new parameter introduced in this study, is found to be more predictable and reliable to measure craniofacial growth. Prenatal growth influences postnatal growth. Ultrasonography as a diagnostic tool holds a remarkable future in orthodontics as a noninvasive and cost-effective technique.
Financial support and sponsorship
Nil.
Conflicts of interest
There are no conflicts of interest.
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