Importance and ways of fetal station measurement: designing and creating fetal station cymbal

Birth includes the period with strong uterine contractions. Accurate diagnosis of fetal station at delivery urinary tract is important for select a delivery method that result in providing health of mother and baby. The present study aims to investigate the methods for determining the fetal station during normal delivery and mistakes of determining fetal head station can result in labor disturbances. In this study, we investigated more than 40 articles in the field of fetal station exam. These articles are available on the scholar indexes such as PubMed and Google Scholar. The present study aims to investigate the methods for determining the fetal station during normal delivery and mistakes of determining fetal head station . RESULTS AND CONCLUSIONS vaginal examination is not a reliable method to assess the delivery status and the amount of descent. The studies have introduced sonography as the gold standard for assessing the status of delivery in the second stage of labor. However, due to the high cost, complexity, and the need for professional personnel to use this method, it is not available everywhere. Therefore, a simple and inexpensive method is required to be designed. The researchers of the present study designed an instrument for assessing fetal station even in disadvantaged and remote areas with little training. Definition of fetal station Fetal station at normal vaginal delivery is described by the relationship between the fetus and the ischial spines located in the entrance and outgoing mouths of the pelvis. In the past, the longitudinal axis of the cervical canal at the top and bottom of the ischial spines was divided into to 3 or 5 parts (each about 1 cm). In 1988, The American College of Nurse-Midwives (ACNM) used a new method for fetal station and divided the upper and lower of the ischial spines to 5 parts. When the lowest presenting part of the fetus is in the same level as the ischial spines, fetal station is zero. On the other hand, if the presenting part of the fetus is in the upper part of the ischial spines, fetal station has a negative score from -1 (closer to ischial spines) to -5 (farther from ischial spines). However, in case it is in the lower part of the ischial spines, fetal station has a positive score from +1 (closer to ischial spines) to +5 (farther from ischial spines). +5 station is applied to the situations in which the head of the fetus is visible at the entrance of the vagina(Cunningham, 2010) .the term “Descent” is defined as the passage of the fetus in the the mother's pelvis, which is the first prerequisite to vaginal childbirth. Diagnosis of fetal station is essential for understanding the degree of descent(Ghi et al,2009). In primiparous women, engagement may occur before the beginning of the labor mechanism, eventually stopping the descent process. In multiparous women, Intl. Res. J. Appl. Basic. Sci. Vol., 7 (14), 1141-1146, 2013 1142 however, descent usually starts with the beginning of engagement. According to ACNM criteria, descent is considered to be prolonged in case it is less than 1 cm/hour in primiparous women and less than 2 cm/hour in multiparous ones. Furthermore, more than 1 hour stop in the descent process is considered as the criterion for diagnosis of descent arrest in both primiparous and multiparous women(Cunningham, 2010). Importance of accurate measurement Estimation of the amount of descent is an important part of the clinical examination and one of the important factors in diagnosis of dystocia and early diagnosis of delivery stop (Cunningham, 2010; Buchmann, 2008). Dystocia is one of the most common indications of caesarean section and about 60 percent of caesarean section cases are related to the diagnosis of dystocia in the United States. Therefore, discontinuation of the descent in the second stage of delivery is one of the prevalent indications of caesarean section (Cunningham, 2010; Barbera and Pombar, 2009). One of the reasons for increase in the amount of caesarean section due to dystocia is wrong diagnosis. Based on many studies, determining the fetal station has an effective role in diagnosis of dystocia and selection of the type of delivery ( Barbera and Pombar, 2009; Barbera and Imani, 2009 ). The statistics indicate an increase in the rate of caesarean section. For example in 2009, 32.9% of all the deliveries in the United States were carried out through the caesarean section. This measure was obtained as 37.7% in South Korea in 2008, 39.8% in Italy in 2007, and 30.6% in Australia in 2007. In Iran, the rate of caesarean section increased from 35% in 2000 to 40.4% in 2005. Studies have shown that this trend continues to grow in this country (Shahraki Sanavi, 2012; Sharifizad, 2012). The rate of caesarean section in Iran is 3 to 4 times higher than the acceptable rate by World Health Organization. Caesarean section is accompanied by a larger number of complications compared normal delivery. Some of these complications include uterine infection, fever, infection in incision site, bleeding, anesthesia complications, urinary system damage, and thromboembolism. The cost and length of hospital stay were also higher in the caesarean section compared to natural childbirth (Cunningham, 2010; Mostafazade, 2006). Moreover, the mortality and disability rate in the caesarean section were respectively 2 to 3 and 5 to 10 times more than natural childbirth (Cunningham, 2010). One of the most important fertility health issues are newborn's and mother's health and mortality. Furthermore, the health indexes of newborns and mothers are related to the health conditions of any society. Therefore, decrease in the rate of c-section is of great importance (Sharifizad, 2012). Constant and accurate monitoring of clinical symptoms, such as measurement of fetal station, can correct the diagnosis of birth disorders and reduce the rate of c-section (Sallam, 1999). Physicians' information about fetal station can also help diagnose abnormal childbirth patterns and make appropriate interferences (Nizard et al, 2009). Dupuis and his colleagues investigated the clinical reliability of “fetal station diagnosis", according to ACNM criteria, by a birth simulator. They reported that the results of the clinical examinations were wrong in one third of the cases ( Dupuis et al, 2005).