Received: 01-Apr-2022, Manuscript No. amhsr-22-52341; Editor assigned: 04-Apr-2022, Pre QC No. amhsr-22-52341(PQ); Accepted Date: Apr 29, 2022 ; Reviewed: 19-Apr-2022 QC No. amhsr-22-52341; Revised: 25-Apr-2022, Manuscript No. amhsr-22-52341(R); Published: 29-Apr-2022, DOI: 10.54608.annalsmedical.2022.36

Citation: Asl LY, et al. Normal Range of Inferior Facial Angle (IFA) During the First Trimester to the Diagnosis of Micrognathia. Ann Med Health Sci Res. 2022;12:121-124.

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Abstract

Introduction: Fetal facial malformations such as micrognathia, maxillary dysplasia, cleft lip and palate, as well as absence of nasal bone have been defined to be associated with some chromosomal abnormalities or genetic syndrome. Ultrasonography can show these parameters exactly. Proper imaging allows medical staff and radiologists to better examine the anatomy of the fetal face and make a more accurate diagnosis. The current study aimed at establishing the reference range for IFA and analyzing its association with fetal micrognathia during the first trimester.

Materials & Methods: This cross-sectional study was performed on pregnant women with a gestational age of 18 to 28 weeks referred to Shahid Akbarabadi Hospital in Tehran. After visiting, informations including age of mother and gestational age was recorded. Then results of ultrasonography test was registered. After childbirth, infants were examed and assigned in to one of the 2 groups. After that, records of IFA were analyzed in both groups.

Results: In the present study, 329 eligible mothers included in the study. We recorded their information and IFA of their fetus. Average age of mothers was determined 30/996/20. Furthermore, gestational age ranged from 17 w+3 d to 27 w. Moreovere, minimum and maximum of IFA were 48 and 79, respectively. Average of IFA was also recorded to be 60/865/69. 2 of the fetuses had abnormality after birth (IFAs 48 and 49). This study showed a significant association of IFA with abnormality of mandible after birth and abnormality of mandible in fetus with lower IFA was found to be more probable.

Conclusion: Our results showed an average of 60/865/69 for IFA, indicating that average of IFA in Iranian fetuses is less than most of the world. This study also revealed a significant association of IFA with abnormality of mandible after birth, Howevere, comprehensive studies with large abnormal samples are nedeed to assess fetuses with lower IFA.

Keywords

Mandible; Ultrasonography; Gestational age; Inferior facial angle

Introduction

The development of the mandible occurs in the sixth gestational week and this complex developmental cascade depends on the fusion of various different embryonic components and complex interactions involving ectoderm of branchial arches and neural crest cells originating in the dorsal neural tube. [1,2]

As a matter of fact, several elements are involved in fetal mandible formation from different embryonic components to interact and fuse, where is more likely to be susceptible to a series of molecular and genetic insults. [1] Mandibular changes should be considered as alarm bells because they are associated with many syndromes and abnormalities. Jaw and facial abnormalities have a direct impact on fetal survival and can lead to numerous respiratory and swallowing problems. Fetal facial malformations such as micrognathia, maxillary dysplasia, cleft lip and palate, as well as absence of nasal bone have been defined to be associated with some chromosomal abnormalities or genetic syndrome. [3,4]

One of these abnormalities, including micrognatia, is a subtle facial abnormality featured by a small mandible and a receding chin. The micrognathia that occurs following neural crest cell hypoplasia can occur independently but is often associated with other abnormalities, e.g., chromosomal abnormalities, skeletal dysplasia, and various syndromes (Pierre Robin sequence, trisomy 13 and 18). [5-8]

Nowadays, micrognathia can be diagnosed via ultrasonography because of its typical ultrasonography features. [2] The Inferior Facial Angle (IFA), measured in a sagittal view of the facial profile, is capable of identifying micrognathia, leading to the differential diagnosis. [8] The jaw index, an axial view of the fetal mandible and the mandibular/maxillar width, can be helpful in assessing the severity of the micrognathia. Fetal Magnetic Resonance Imaging (MRI) can be helpful to assess the severity of fetal micrognathia evaluating a potential obstruction of the airway. [9] Proper imaging allows medical staff and radiologists to better examine the anatomy of the fetal face and make a more accurate diagnosis. [10] Nonetheless, prenatal diagnosis of fetal facial abnormalities in the first trimester is still a challenge, and a number of reliable and repeatable objective parameters are not accessible. In this study, fetal facial marker including IFA were measured in fetal facial mid-sagittal section [Figure 1].

Figure 1: Linear regression between the two variables gestational age and IFA in the subjects.

The current study aimed at establishing the reference range for IFA and analyzing its association with fetal micrognathia during the first trimester. As a matter of fact, the present study was conducted to find the normal range of IFA in Iranian embryos and to provide a suitable diagnostic test.

Materials and Methods

Sampling

This cross-sectional study was performed on pregnant women with a gestational age of 18 weeks to 28 weeks referred to Shahid Akbarabadi Hospital in Tehran. According to the studies performed, the sample size of 300 was determined using the following formula:

The required sample is also collected by convenience sampling method. The checklists are then completed and the tests performed.

Data collection

After obtaining permission from the research assistant and relevant authorities, the information of patients referred to the relevant ward in Shahid Akbarabadi Hospital was extracted and the IFA was measured in normal fetuses.

Inclusion criteria included mothers with a gestational age of 18 weeks to 28 weeks and normal screening ultrasound. Exclusion criteria include: embryos with abnormalities

After birth, the infants examined and placed in two groups of abnormal and healthy. After birth, infants are examined for micrognathia and swallowing to compare the normal range of the IFA for both healthy and abnormal groups. The necessary information such as age and gestational age were recorded. Then the sonographic test was performed and the results were recorded in a checklist.

IFA was measured during the first trimester when the fetus was examined for nuchal translucency and nasal bone. The midsagittal surface was precisely defined by the baby tip in the front, the translucent diencephalon in the middle, the nuchal membrane in the back, and the roof of the mouth.

IFA is measured by defining a right-angled line from the vector drawn at the synostosis of the nasal bones to the vertical part of the forehead, at the synostosis level of the nasal bones, and the vector joining the tip of the mentum the anterior margin of the more protruding part of the lip.

Then the normal range of IFA and its condition in the patient group was examined. Naturally, an appropriate test would be one that identifies more patients and is positive in a smaller number of healthy people.

Data analysis

The information received in the answer sheet and test results were entered into SPSS software version 21. Then, the relationship between the desired factors is statistically examined by Chisquare test. All tests are performed by considering a significance level alpha=0.05.

Ethical considerations

Patients 'personal information was kept throughout the research and the individuals' information was entered into the software with a checklist code.

Results

In this study, we examined 328 people who were eligible to participate in the study. Preliminary data were recorded and fetal IFA was measured. The mean age of mothers was found to be 30.99 ± 6.20. The gestational age of the subjects was from 17 w+3 d to 27 w. Tables 1 and 2 show the demographic information of the subjects.