A Study on Estimation of Fetal Weight in Term Pregnancy by Clinical Methods and USG and Comparison with Actual Birth Weight

Sowbharnika, C P (2020) A Study on Estimation of Fetal Weight in Term Pregnancy by Clinical Methods and USG and Comparison with Actual Birth Weight. Masters thesis, Sree Mookambika Institute of Medical Sciences, Kulasekharam.


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AIM OF THE STUDY: The aim of the study is to assess fetal weight by clinical methods using Johnson’s formula and Dare’s formula and by ultrasound, using Hadlock’s formula .Then the accuracy of estimated fetal weight by USG and clinical methods was found out by correlating with actual birth weight. METHODS: Total 100 women are included in the study. A detailed history was taken which included the patient’s education, occupation, socio-economic status, menstrual history, obstetric history, past medical and surgical history and personal history. A thorough general physical examination was done. Vitals signs and all systems were examined. After a brief general physical examination, per abdomen examination was performed in supine position. The symphysio fundal height and abdominal girth was measured and estimated fetal weight was calculated using Johnsons formula and Dares formula. Then ultrasonogram was taken and head circumference, biparietal diameter, abdominal circumference and femur length was measured and estimated fetal weight was calculated with inbuilt Hadlock’s formula. After delivery the actual birth weight of the baby was measured using electronic fetal weighing machine. Predicted estimated fetal weight by each method was compared with respective neonatal actual birth weight. RESULTS: Out of 100 pregnant women included in a study 19 women belong to upper socioeconomic class 51 women belong to middle socioeconomic class (upper middle and lower middle) and 20 women belong to lower socioeconomic class (upper lower and lower). Among these patients women belonging to lower socioeconomic class had low birth weight babies with average weight of 2312 grams. There was gradual increase in actual birth weight with higher socio economic classes. Women with pre pregnancy weight of more than 45 kg (90%) had higher average birth weight of the baby. Women with more than7 kg of weight gain during pregnancy had increased weight of babies compared to mothers with weight gain of less than 7 kg with difference in mean weight of 421 grams. This study showed women with height of > 150 cm (88%) and multigravida women (44%) had higher birth weight babies. Male babies weighed more than female babies with mean birth weight of 64 grams more in male babies compared to female babies. In USG estimation of fetal weight 53%nof cases were within the range of ±100 grams. The difference between mean USG estimated fetal weight and mean actual weight was 13.10 grams. By Johnsons formula 53% were within ±250 grams and by Dares formula 52% were within ±250 grams. When compared with actual birth weight the difference was 87.27 grams and 145.9 grams by Johnsons formula and Dares formula respectively. When birth weight was < 2500 grams all the methods overestimated the fetal weights and when birth weight was >3500 grams all the methods under estimated the fetal weights. Among all the three methods USG was more accurate in estimating the fetal weight. CONCLUSION: Among the two clinical methods Johnsons method of fetal weight estimation was found to be more reliable when clinical methods were compared with USG, ultrasonogram method of fetal weight estimation was found to be more accurate. Thus USG is more reliable in prediction of fetal weight than clinical methods and Johnsons formula can be used in resource limited settings.

Item Type: Thesis (Masters)
Additional Information: 221716602
Uncontrolled Keywords: Fetal birth weight, Johnsons formula, Dares formula, Hadlocks formula, maternal weight and height.
Subjects: MEDICAL > Obstetrics and Gynaecology
Depositing User: Subramani R
Date Deposited: 18 Feb 2021 17:27
Last Modified: 18 Feb 2021 17:27
URI: http://repository-tnmgrmu.ac.in/id/eprint/14317

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