Calculators & Tools

Calculators & Tools

Welcome! This page contains all of the links, calculators, and charts that you may need to monitor your baby. Here you can find out how to calculate your baby’s MoM, determine what percentile your baby is in (estimated fetal weight), and what the survival rate is if your baby was born today. These tools work no matter what red cell antibody is affecting your pregnancy (anti-E, anti-c, anti-G, anti-Kpa, anti-Jkb, etc). After your child is born, you can find out what the treatment thresholds are for bilirubin, what the normal lab values for HDFN are, and what your baby’s weight for age percentile is.

Where Can I Calculate My Baby's MoM?

There are two ways to know your baby’s MoM: ask your physician or calculate it yourself. In order to calculate the MoM yourself, ask your ultrasound tech or physician what your baby’s Peak Systolic Velocity (PSV) is. Sometimes this number is called the Vmax or Max Velocity. Click on Anemia > Cerebral Doppler. Enter your baby’s gestational age and the PSV and calculate the MoM.

Source: Fetal Medicine Barcelona.

You may also want to print off a copy of the chart below. If you memorize the PSV for the 1.5 number, and ask the ultrasound technician for the max velocity, you will know immediately how close your baby is to a 1.5 MoM.

I have my baby's estimated fetal weight. Where can I go to find out what percentile he is in?

Once you have your baby’s estimated fetal weight (EFW), convert it to grams. Click on Fetal Growth > Gestational Age. Enter your baby’s gestational age and the EFW. Select the child’s gender and click calculate to see what percentile your baby is in.

Source: Fetal Medicine Barcelona.

You may also want to print off a copy of the chart below.

If my baby was born today, what are her chances of survival?

Medical care is rapidly advancing and improving. With care at a high level Neonatal Intensive Care Unit (NICU), the survival rates for infants born early are improving. These survival rates do not take into account HDFN, but give you an idea of the survival rates for infants born at 22-38 weeks gestation.

Sources: Should newborns at 22 or 23 weeks’ gestational age be aggressively resuscitated?, When is it safe to deliver? From University of Utah Health and Premature Birth and Viability from Very Well Family.

I have my newborn's bilirubin levels.
Is he near the treatment limits?

Infants with HDFN (those who have a positive DAT or are antigen positive) are at medium risk (infants born at/after 38 weeks gestation with risk factors)or high risk (infants born at 35 to 37 6/7 weeks with risk factors)for complications due to high bilirubin. You can enter your child’s numbers in the calculator below. Remember to change the units if you are in the UK or another country that does not use mg/dL.

Source: Peditools.

You may also want to print off a copy of the chart below.

What are the normal lab values for ferritin, hemoglobin, hematocrit, neutrophil count, and thrombocyte count?

Infants with HDFN face 4 main complications: hyperbilirubinemia, anemia, neutropenia, and thrombocytopenia. As a result, your baby should receive blood tests for his hemoglobin (to detect anemia), hematocrit (to detect anemia), neutrophil count (to detect neutropenia), and thrombocyte count (to detect thrombocytopenia).Your baby’s ferritin level should also be tested before any iron supplements are given. Ferritin – A blood test performed to measure the amount of iron in the bloodstream. A ferritin test should be performed before iron supplements are given to infants with HDFN. Normal ferritin range for newborns is 25-200 ng/mL. The normal range for infants from 1-5 months old is 50-200 ng/mL. Hematocrit – Hematocrit is a blood test that measures the percentage of the volume of whole blood that is made up of red blood cells and is used as an indicator of anemia. The normal hematocrit range for infants 0-6 months is 37.4 – 55.9% for females, and 43.4 – 56.1% for males. A fetal hematocrit of less than 30% is considered anemia.

Hemoglobin – Hemoglobin is a protein in red blood cells that carries oxygen. A blood test can tell how much hemoglobin you have in your blood and is used as an indicator of anemia (common in the USA). The normal pediatric hemoglobin range for infants age 0-6 months is 12.7 – 18.3 g/dL for females and 14.7 – 18.6 g/dL for males.

Neutrophil count – Normal neutrophil levels range from 6 – 26 x 109/L for newborns, and decrease to 1 – 9 x 109/L at 1 month of age.

Thrombocyte count – Normal platelet levels are >150 x 109/L. This value is the same regardless of age. Approximately 25% of infants with HDFN experience thrombocytopenia, a reduced level of thrombocytes.

For additional reading about what tests infants with HDFN need and how often, see our Resource Library page on Necessary Laboratory Assessments for Infants Exposed to Maternal Alloantibodies.

What percentile is my baby in for growth?

Below are calculators for infants weight for age percentile.

WHO Growth Chart 0-2 years old

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