Measurement of the palpebral fissure and the vermilion border of the upper lip in newborns with gestational ages of 25 to 43 weeks

Objective: To prepare percentile curves for measurements of palpebral fissure and the greatest width of the vermilion border of the upper lip in newborns at a public maternity ward in the City of São Paulo. Methods: A descriptive cross-sectional study was carried out from August 2006 to January 2008. In the first 24 to 72 hours of life, the palpebral fissure and the greatest width of the vermilion border of the upper lip were measured in 1,964 newborns with gestational ages from 25 to 43 weeks. Percentile curves corresponding to these measurements were prepared according to gestational age. Results: The average measurement of palpebral fissure was 1.98 cm, ranging from 0.80 to 3.00 cm, standard deviation ± 0.24 cm. The average measurement of the width of the vermilion border of the upper lip was 0.51 cm, ranging from 0.20 to 0.90 cm, standard deviation ± 0.11 cm. These measurements allowed designing the percentile curves (10th, 50th, and 90th) relative to gestational age. Conclusions: Measurement curves of palpebral fissure and of the greatest width of the vermilion border of the upper lip may be useful to evaluate the presence of facial dimorphism in newborns.


INTRODUCTION
Some characteristics of eyelids and lips, such as their measurements, are data that cannot be omitted from analysis in the physical examination of newborns.
Towards the 48 th day of the embryo, formation of the upper lip is completed through fusion of the two upper maxillary and the two nasomedial processes emerging from the first arch (1) .
By the 6 th week, small folds of ectoderm with mesenchymal core appear just cranially and caudally to the developing cornea.These upper and lower primordial eyelids rapidly grow toward each other, meeting and fusing by the 8 th week.The eyelids separate again between the 5 th and 7 th months (2) .
The palpebral fissure develops more quickly than the eye (3) .However, the length of the palpebral fissure directly correlates with the size of the ocular globe (4,5) .The development of the palpebral fissure does not depend solely on the development of the eye (3) .Since the eye is a neuronal organ, the length of the palpebral fissure may indirectly reflect a neurological growth problem (4) .Nevertheless, an alteration in the measurements of the palpebral fissure may also be related to abnormalities in the development of the soft tissue around the eyes (4) .
Many syndromes present with congenital malformations in the eyelids and/or thinner upper lips, such as the fetal alcohol syndrome (FAS), Kabuki syndrome, trisomy 13, trisomy 18, among others (6) .FAS, the most frequent, is a permanent birth defect caused by maternal consumption of alcohol during pregnancy and it currently represents a major public health issue worldwide (7)(8)(9) .The estimated prevalence of FAS varies from 0.5 to 2 cases/1,000 live births (9,10) .Based on this prevalence, the Center for Disease Control and Prevention (CDC) expects there will be 1,000 to 6,000 children with FAS born every year, with approximately 4 million children born with prenatal alcohol exposure.These rates are higher than those found for other common developmental disabilities such as Down's syndrome or spina bifida (10) .
The well-known adverse effects of prenatal exposure to alcohol, however, are underdiagnosed, since healthcare professionals are unprepared to make this diagnosis and because social prejudice in pregnancy causes women to hide their alcohol-consuming habits (10,11) .The diagnosis of FAS in the newborn implies the presence of three facial characteristics: small palpebral fissure, thin upper lip, and smoothness of the philtrum, plus intrauterine growth restriction and abnormalities of the central nervous system in multiple ways (7,10) .Consequently, early identification and diagnosis of FAS in affected newborns recognized by the abovementioned characteristics are essential in order to provide health, education, and social services that may guarantee optimal well-being to these children and their families (10) .
Even though some international publications describe the measurement of palpebral fissures in newborns, no reports of these measurements regarding the Brazilian population in the newborn period were found in any study.The same is true in relation to the greatest width of the vermilion border of the upper lip.
Therefore, the construction of percentile curves for the measurements of palpebral fissure and vermilion border of the upper lip in the Brazilian population must be a valid goal for neonatologists.

OBJECTIVE
To construct percentile curves for measurements of palpebral fissure length and the greatest width of the vermilion border of the upper lip in newborns at the Hospital e Maternidade-Escola Municipal Dr. Mário de Moraes Altenfelder Silva da Vila Nova Cachoeirinha (HMEVNC).

METHODS
This is a descriptive cross-sectional study carried out from August 13, 2006 to January 21, 2008 at HMEVNC, a public hospital in the City of São Paulo, located in the Northern area of the city, in Brasilândia district.This maternity hospital serves a low-income and highly mixed race population.It is a reference tertiary hospital for high-risk pregnancies, and also treats normal pregnant women belonging to this specific geographical area.
During this period, there were 7,447 live births at the hospital and 33 live children who were admitted to hospital after birth.For operational reasons, due to availability of one of the researchers (MAM), the live newborns admitted during the above-mentioned period, between 00:01 AM on Sundays and 11:59 PM on Mondays, were included.Newborns who presented with a genetic syndrome, died, were transferred to another hospital or discharged prior to their physical examination, whose mother died, who were not the first born in case of twins, or who were children of women refusing to participate in the study were excluded.
Data were collected on gestational age and measurements of the palpebral fissure and greatest width of the vermilion border of the upper lip of the newborns.
Gestational age was estimated by using the last menstrual period calculated by Naegeles' rule (12) , by using the New Ballard Score (13) obtained between the 6 th and the 48 th hour of life, or by the Capurro method (14) carried out during the first hour of life, when the newborn clinical condition precluded examination to be done using the New Ballard Score.The gestational age was determined through the New Ballard Score or the Capurro method when the mothers last menstrual period was unknown.Preterm newborns were defined as those whose gestational age was less than 37 weeks, term newborns as gestational age of 37 complete weeks to 41 weeks 6/7 days, and post-term newborns as gestational age equal to or above 42 weeks (15) .
The vermilion border is the exposed mucous membrane or red portion of the upper lip, and the palpebral fissure length is the distance from the eye endocanthion to its exocanthion (16) .
The palpebral fissure and the greatest width of the vermilion border of the upper lip were measured with a rigid plastic ruler marked with 1 mm intervals.The measurement of the palpebral fissure was taken with the ruler at the greatest horizontal axis between the eye endocanthion and its exocanthion.The greatest width of the vermilion border of the upper lip was obtained with the same type of ruler at the greatest vertical axis, between the labial commissure and the upper border of the upper lip.Measurements were registered in centimeters and were taken with the patient's eyes closed, due to the difficulty of children this age opening their eyes, and with their lips sealed (Figure 1).6 (0.29%) were excluded from the study for the presence of syndromes, 11 (0.54%) because they died before having their physical examination, 7 (0.34%) for having been discharged from hospital before their physical examination, 1 (0.05%) due to the fact of being transferred to another hospital before the physical examination, 1 (0.05%) because the mother died before the physical examination, and 9 (0.44%) because their mothers refused to participate.Of the 2,000 (98.28%) children who remained, 36 were of twin pregnancies and the second twin was not considered.Thus the sample for analysis consisted of 1,964 newborns (96.51%).
With regard to gestational age, of the 1,964 newborns, 312 (15.90%) were premature, 1,631 (83.04%) were full term and 21 (1.06%) were postterm.The average gestational age was 38.55 weeks, ranging from 25.0 to 43 weeks and a standard deviation of 2.49 weeks.The mean birth weight was 3,048.51g, range of 540 g to 5,680 g, and a standard deviation of 613.32 g, and 92% of the children (n = 1,807) were appropriate for gestational age.
Table 1 shows the average measurement of the palpebral fi ssure, its variation and standard deviation, as well as the measurement of the greatest width of the vermilion border of the upper lip with its variation and standard deviation.Measuring of the palpebral fi ssure and the vermilion border of the upper lip was carried out at between 24 and 72 hours of life, so that the subcutaneous edema from labor and birth would not induce error.The newborn was lying on the crib, in supine position, in either a state of quiet sleep or quiet alert.
Data collection and anthropometric measurements of the newborns were carried out by only one of the researchers (MAM).
The measurements of palpebral fi ssure and greatest width of the vermilion border of the upper lip of these children, together with their gestational age, allowed the construction of the respective percentile curves for these measurements.For each curve, the 10th, 50th, and 90th percentiles were determined according to gestational age.
The newborn participation in the study was consented to after their mothers had read and signed the Parental or Legal Guardian Consent Form.
The study was approved by the HMEVNC Research Ethics Committee under protocol number 009/2006.

RESULTS
During the study period, 7,480 live children were born, with 7,447 hospital births and 33 births outside the hospital.Of this total, 2,035 were eligible to participate in the research because they were born between 00:01 AM on Sundays and 11:59 PM on Mondays.However,  city of São Paulo because of racial characteristics.However, further studies on the theme should be done and we dare say that this may be a first step towards stimulating the construction of other percentile curves in other centers, according to the characteristics of their own populations.This study did not show comparisons of these curves to others in literature, as this was not its objective.

CONCLUSION
The percentile curves for the measurements of the palpebral fissure length and the greatest width of the vermilion border of the upper lip according to gestational age, in a population of a maternity hospital in the city of São Paulo, were presented in this study.
These data can be useful in the physical evaluation of newborns in this population, as in the early diagnosis of dysmorphic characteristics and syndromic anomalies.They allow for a more precise and objective quantitative description of these structures, avoiding subjective evaluations.

Figure 1 .
Figure 1.Measurements of palpebral fi ssure and vermillion border of superior lip "a" = palpebral fi ssure length and "b" = vermillion border width

Figure 2 .
Figure 2. Percentile curve of measurement of palpebral fi ssure

Figures 2
Figures2 and 3show the percentile curves (10th, 50th, and 90th percentiles) obtained with the measurements of palpebral fi ssure and the greatest width of the vermilion border of the upper lip according to gestational age.