Birthweight Estimate Calculator v 2.1
by Jennifer N. Ayers-Gould, BA, LPN, ICCE

Do you really need that c-section, episiotomy, or induction because of a "big" baby? 
Find out how much you can expect your "little bundle" to weigh.

Based on the recently published scientific research of a renowned physician in the Journal of Reproductive Medicine, this calculator will determine your unborn baby's estimated current weight as well as estimated weights for 38, 40, and 42 weeks gestation (dated from first day of last normal menstrual period). 
 
Please Note:  This is only accurate for predicting fetal/birth weight in the third trimester of pregnancy (weeks 28 - 42 from first day of last normal menstrual period).  The calculator will not provide accurate results for multiple gestation pregnancies, or for women who suffer from pregnancy-related illnesses which may contribute to excessive weight gain/loss such as hyperemesis gravidarum or gestational diabetes.  Other factors affecting the accuracy include race (these calculations were created based on Caucasian mothers and may not be as accurate for other races), and if the mother is a smoker, birthweight may be lower than predicted. The Birthweight Estimate Calculator is most accurate in estimating the baby's birth weight for healthy, non-smoking, Caucasian women with a single intrauterine pregnancy. If you enter information inaccurately or guess at any of the data, your results will not be as precise.

After submitting your valid data to the Birthweight Estimate Calculator, a page will be displayed showing what you've entered and the results of fetal and birth weight estimations for the current status of your pregnancy (how much your baby currently weighs), and also for 38, 40, and 42 weeks gestation, which can give you an idea of what your baby will weigh when born at various full term dates.  You will also be sent the results via email.  After your 6 month license period has expired, you will be sent an email which will ask you to enter the actual birth date, weight, and gender of your baby so that you may compare it with the results you received when you used the Birthweight Estimate Calculator.  Those who have previously used the calculator to estimate the weights of their unborn babies have had great accuracy when compared with the actual birthweight's.  The Birthweight Estimate Calculator has had similar accuracy to that of an ultrasonic scan, without the risk of exposing your unborn baby unnecessarily to ultrasonic radiation, or paying for the high cost of using such technology.

[ Click Here to View Sample Report ]

There is a one-time charge of $11.11 (USD)* to utilize the Birthweight Estimate Calculator program.  This fee helps to cover the cost of development, testing, programming, research, hosting and web design.  A similar program on the Internet costs $25.00!  There is nothing else like this anywhere -- and not at such a reasonable price.  The fee also helps to discourage fraudulent usage which ties up server resources.  Once you have purchased access to the Birthweight Estimate Calculator, you will be given unlimited individual access** to the program for a period of 6 months following your initial purchase.  To continue, please click on the Buy Now button below to process your payment and gain immediate access to the Birthweight Estimate Calculator.  Information on how to access the Birthweight Estimate Calculator will be automatically sent to you via email as soon as your secure online payment has been processed.  Thank You!

Report any problems/bugs/comments to:  birthsong@starr-rhapsody.com

The Research Behind the Birthweight Estimate Calculator:

Validation of a Birth Weight Prediction Equation Based on Maternal Characteristics
Gerard G. Nahum, M.D., and Harold Stanislaw, Ph.D.

OBJECTIVE: To validate the accuracy of a birth weight prediction equation based on maternal and pregnancy-specific characteristics and to assess its value in predicting fetal macrosomia.
STUDY DESIGN: A previously published birth weight prediction equation based on maternal and pregnancy-specific characteristics was used to predict birth weight in 244 Caucasian gravidas with uncomplicated, singleton, term pregnancies. Results were assessed by calculating the mean absolute error, the mean absolute percentage error and the percentage of birth weights correctly predicted to within ±10% and ±15% of actual birth weight. The sensitivity, specificity and positive and negative predictive value for predicting fetal weight >4,000 g were calculated.
RESULTS: Birth weight was accurately predicted to within an average of ±8.1% (±280 g). The percentage of weights accurately predicted to within 15% of actual birth weight was 87%, and the percentage predicted to within ±10% was 68%. The sensitivity for predicting fetal weight >4,000 g was 52%, specificity 90%, positive predictive value 42% and negative predictive value 93%. The area under the receiver operating characteristic curve for predicting fetal macrosomia was 0.83.
CONCLUSION: An equation using maternal and pregnancy-specific characteristics can predict term birth weight in gravidas with uncomplicated singleton pregnancies to within ±8.1% (±280 g). The accuracy of the method for predicting birth weight >4,000 g is comparable to that obtained using ultrasonic fetal biometry. (J Reprod Med 2002;47:752–760)

http://www.jreprodmed.com/Features/2002/2002Sep.htm