Allo Pregnancy Timeline

Welcome! Going through a high-risk pregnancy is incredibly difficult, especially when you don't know what to expect. We at the Allo Hope Foundation wanted to help patients and their families know what to expect by offering a pregnancy timeline. Simply click on a gestation below to see the essentials, things to be aware of, and the silver lining for each week of pregnancy. If you aren’t certain what a term means, click over to our Glossary. When you are finished reading through the timeline, be sure to check out the Resource Library for more detailed information about alloimmunization and HDFN.

Disclaimer: The purpose of this website is to provide general education, access to resources, and relevant literature. This website does not provide specific medical advice or recommendations for individual patients and is not a substitute for speaking with qualified healthcare professionals. The Allo Hope Foundation strongly recommends that care and treatment related to alloimmunization and HDFN be made in consultation with your physicians who are familiar with your individual health situation.

Essentials:

For those who have had a previously affected pregnancy, a preconception appointment with your MFM, or potential MFM, can be helpful. If you had a severely affected pregnancy or lost a baby to HDFN in the past we strongly recommend having a preconception appointment with an MFM before attempting another pregnancy.

During your preconception appointment you can discuss any questions or concerns you may have about a future pregnancy. You can work together with your MFM to create a care plan that you and your partner feel confident about. Having a face to face meeting also helps you get a feel for the MFM’s bedside manner and how you both interact with each other. It is also helpful to see how your MFM handles questions from you since you will be asking lots of questions during a future pregnancy. For those who have lost a baby to HDFN, the preconception appointment is a good time to ask your MFM questions about your experience and discuss ways to prevent another loss.

Click here for a list of possible preconception questions to help guide you through your appointment.

Be aware:

It can be helpful to check your antibody titer during your preconception appointment, just to get a starting point, but be aware that titers often change once a woman becomes pregnant. Your titer before pregnancy is not always an accurate predictor of how your pregnancy will go or how affected your baby might be.

Silver Lining:

No one is in danger at the moment so you can rest easy and focus on making a good plan for the future. You can choose an MFM that you feel confident about, BE PICKY.
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Essentials:

If you have had a previous pregnancy that was severely affected, have lost a baby to HDFN, or if your titers are in the hundreds/thousands:

It is recommended that you have your first appointment with your MFM as early as possible. Certain treatments such as plasmapheresis and IVIG, must be scheduled during this time period and can take weeks to be approved by insurance companies. Because these treatments are very time sensitive and are the most effective when started by a certain gestation, getting in to see your MFM early in the pregnancy is a great way to keep your baby safe.

Everyone:

Antibody Screen and Titer Check- You should be given an antibody screen and your titers should be checked. Dating Ultrasound- Early ultrasounds are the most accurate for dating purposes so it is helpful to have a dating ultrasound, especially if you aren’t sure about the dates of conception or your last menstrual period. Knowing the baby’s accurate due date is very important during an alloimmunized pregnancy since many of the essential monitoring protocols and treatments are based on gestational age.

Be aware:

Miscarriages at this stage can sensitize a woman to develop alloantibodies. First trimester bleeding for any reason requires Rh Immune Globulin (RhoGAM) if you are Rh negative, unless you already have anti-D antibodies.

Silver Lining:

Your baby is completely safe from your antibodies at this point. Red cell antibodies cannot harm the baby during this time period so rest in the fact that your baby is safe from your antibodies right now.
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Essentials:

If your titers are not critical:

You should be having your first or second titer test now.

If your titers are critical:

For those having plasmapheresis and IVIG treatments, plasmapheresis is recommended between 10-11 weeks and IVIG should start immediately after plasmapheresis is finished (11-12 weeks). Some women have a port or a permacath (or both) surgically implanted before starting treatments.

Everyone:

If this is your first sensitized pregnancy, or first pregnancy with your partner, now is the time to have your partner’s blood tested for the antigens. The baby’s father should be phenotyped for any of the matching antigens that you have antibodies to. For example, if you tested positive for anti-Kell antibodies, your partner needs to be tested for the Kell antigen. This test can be done by your MFM, regular OB or your partner’s regular doctor.

You should be arranging your first MFM appointment now.

If you have anti-D antibodies, you can have the cell free DNA (cffDNA) test to learn whether baby is positive or negative for the D antigen.

Be aware:

Sometimes even medical professionals get confused about the difference between antigens and antibodies. MAKE SURE that the baby’s father is tested for the antigen, NOT the antibody. The best practice is to ask for his test results either on paper or through an online patient portal so that you can see for certain that he was given the right test. Future monitoring and treatment procedures are based on the results of the father’s antigen test, so it is very important that he receives the correct test.

Silver Lining:

It is still too early for your baby to be affected by your antibodies, so try not to worry about whether your antibodies are hurting baby or not.
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Essentials:

If your titers are not critical:

Continue having your titers drawn every 4 weeks.

If your titers are critical:

You should be having weekly MCA scans starting by 18 weeks at the latest.
First MFM appointment: By the end of this time period you should have already had your first appointment with your MFM.
First MCA Scan: Probably the most important essential for this gestation is the start of MCA scans. If you have a critical titer you should start weekly MCA scans by 16-18 weeks. If you have anti-Kell it is a good idea to still have mca scans even without a critical titer since Kell has been known to affect the fetus even with low titers.

Everyone:

Father’s Antigen Status - You should know or find out baby’s father’s antigen status. Is he positive or negative for the antigen? Homozygous or heterozygous for the antigen?

Cell Free Fetal DNA Test (cffDNA) - If you have anti-c, anti-E, or anti-Kell antibodies we recommend the free cell fetal DNA test that can be done at 14 weeks and on. It is a reliable, non-invasive way to find out your baby’s antigen status. If baby is antigen negative, then your antibodies cannot harm your baby. If baby is antigen positive you and your MFM will know to keep a closer eye on baby throughout the pregnancy.

Be aware:

This is when the baby could become affected by maternal antibodies in the most extreme cases. Be aware that babies who become severely anemic at this gestation rarely show signs of fetal hydrops. This is why MCA scans are so important. Some common misconceptions you might hear during these gestations are:
“Babies can’t be affected by the antibodies before 19/20 weeks.”
“Nothing can be done to help anemic babies before 19/20 weeks anyway so there's no point in scanning that early.”
“Scans before 18 weeks are not accurate or are too difficult to perform.”
“The MCA-PSV calculator only starts at 18 weeks, therefore no need to start MCA scans earlier.”

Silver Lining:

You have made it to the second trimester! This is a big milestone to celebrate! The risk of having a miscarriage (unrelated to the antibodies) is much lower now that you are out of the first trimester.

By the time you reach 15 or 16 weeks, there are treatment options for babies who become anemic in utero. Even though the risks are higher at such early gestations, IPTs (intraperitoneal transfusions) can be performed by experienced professionals as early as 15 weeks.

MCA Scans can now be performed so you and your doctor can now know whether baby is being affected by the antibodies or not. It is a relief to know exactly how your baby is doing and whether he is anemic or not.
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Essentials:

If your titers are not critical:

Continue having your titers drawn every 4 weeks.

If your titers are critical:

You should now be having weekly MCA scans. You should also talk to your MFM about IUTs. What is their protocol if the MCA scan reaches 1.5 or over? Who would perform the IUT? Would you be referred to another facility for IUTs? How many IUTs has the provider performed in the past year? What is their success rate?

Be aware:

Some care providers consider 22 weeks to be the point of viability. Other care providers consider 23 or 24 weeks to be the cut off for viability. This is important to discuss with your MFM ahead of time so that you can have a plan in place in the rare instance that the baby would need to be delivered at 22-24 weeks (For example, if the baby went into distress during an IUT).

Silver Lining:

IUTs get easier and safer as the baby grows. By now, physicians performing an IUT are usually able to do an IVT (intravenous transfusion) instead of only relying on IPTs (intraperitoneal transfusions.) Babies who have their first IUT after 20 weeks have higher survival rates.
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Essentials:

If your titers are not critical:

Continue having labs drawn every 4 weeks.

If your titers are critical:

Continue having weekly MCA scans.

Everyone:

Consider setting up a tour of the NICU if you think one might help prepare you for your baby's possible NICU stay.

Be aware:

Now that the baby is viable, your MFMs might be considering using steroids to help develop the baby’s lungs if the baby starts showing signs of fetal anemia or if an IUT is coming up. Be aware that steroids can artificially lower MCA scan results. The best course of action is to only administer steroids after the decision to have an IUT has been made.

Silver Lining:

Your baby is now considered viable and could possibly survive outside of the womb if born now. This is a huge milestone to be celebrated! Every week longer in the womb means a higher survival rate for the baby.
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Essentials:

If your titers are not critical:

Titers are now drawn every 2 weeks.

If your titers are critical:

Continue having weekly MCA scans.

Everyone:

If you haven’t already, discuss your delivery plan with your MFM or OB. Pack your hospital bags.

Be aware:

Weekly MCA scans continue to be the best way to monitor your baby for anemia. Some doctors might suggest scanning every two weeks or every month and only moving to weekly scans once MoMs get to 1.3. Unfortunately, fetal anemia can develop within a matter of days so it is important to continue weekly MCA scans if your titers are critical. Remember, fetal anemia can only be treated if it is detected in time.

Silver Lining:

You have now reached the third trimester! Congratulations! Another huge milestone. It is a huge relief to know that it is possible to deliver the baby now if there was a problem in utero.
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Essentials:

If your titers are not critical:

Beginning at 36 weeks, titers are drawn every week until delivery.

If your titers are critical:

Continue weekly MCA scans.

Everyone:

Begin weekly nonstress tests (NST) and biophysical profiles (BPP).
Discuss your delivery plan with your MFM and OB.
Take a tour of the NICU if you haven't already.
Double check that your bags are all packed and ready to go. Bring your bag with you when you go to every appointment.
Begin reading about the care and testing that baby will need after birth.

Be aware:

MCA scans become less reliable after 38 weeks. ACOG, RCOG, and SMFM recommend for all alloimmunized women regardless of titers, to deliver by 37-38 weeks unless baby is antigen negative.

Silver Lining:

Your baby can now be delivered with little to no preemie issues to deal with. You made it!
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Essentials:

At the time of delivery your baby’s care shifts from the MFM to the neonatologist/pediatrician. This can sometimes come as a sudden jolt after being cared for by your MFM for months. Many specialists and clinicians have little experience treating babies with HDFN since it is rare. Go in expecting to be an advocate for your baby. Even though your baby has received months of monitoring and possibly treatment in utero, your baby is born without a medical record. YOU have to be your child’s medical record. Remind your baby’s physicians that they are dealing with hemolytic disease of the fetus and newborn. Remind the physicians that the journey your baby just took in utero does have an effect on what type of care is required after birth to keep your baby safe.

Everyone:

You can print off a list of the tests that baby will need and any important links. The Allo Hope Foundation has made a helpful printable packet with all of the tests, normal lab values, and a place where you can fill in your baby's results. Get your copy here. We use this calculator for baby's bilirubin.

All infants born to mothers with alloimmunization need to have a Direct Agglutination Test (DAT), hemoglobin, and bilirubin run from the umbilical cord blood. Depending on these results, follow up testing will be needed. To read more about testing, visit our page on necessary and optional laboratory testing for neonates exposed to maternal alloantibodies.

Women with anti-C, anti-c, anti-Fya, anti-Good, anti-H, anti-Jra, anti-M, and anti-Mta antibodies:

Your baby's DAT test may be negative, but your child could still be affected. An Indirect Agglutination Test (IAT) or antigen phenotype should be run if you have maternal alloantibodies listed above. These antibodies have been shown to occasionally yield an affected infant despite a negative DAT. You can read more about DAT exceptions here.

Be aware:

Titers do not determine how baby will do after birth. Infants born to mothers with low titers may still struggle with high bilirubin levels and become anemic.

Hemolytic anemia is different from iron deficiency anemia (the type most doctors encounter) and hemolytic jaundice is different from newborn jaundice (the type most doctors encounter). Hemolytic jaundice must be monitored more closely and treated more aggressively. Hemolytic anemia is not resolved with an iron supplement. Your baby is also at risk for delayed onset anemia if the DAT at birth was positive, even if baby did not need IUTs, and even if your baby is not anemic at birth.

Breastfeeding is safe. Feeding your baby often helps remove bilirubin.

If your baby has had IUTs, it is very likely that the majority (or all) of your baby’s blood will be donor blood since the antigen positive blood has been destroyed by your antibodies already. This means that baby will probably be born with a blood type different than his actual blood type. This also means that the newborn screening is actually done on donor blood and not on your child’s actual blood. Make sure to schedule a repeat newborn blood screen test for several weeks after baby's last transfusion (when baby has cleared out the donor blood and replaced it with his own blood.) Also, don’t be too worried if your child’s original newborn screen comes back as abnormal. There have been cases of HDFN babies showing extremely low levels of carnitine on their newborn screening. All of these babies had had IUTs. The mothers were informed that their babies could have an inherited metabolic disorder called “Carnitine Deficiency Disorder” or “Carnitine Uptake Disorder.” When the babies were given repeat newborn screen blood tests several weeks later, all of their carnitine results were normal. No studies have been done to determine what caused the low carnitine levels in the donor blood.

Silver Lining:

Your baby is here! Congratulations! Even though your baby might need more monitoring and treatment, it is much easier and safer to treat the baby on the outside than in utero.
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Essentials:

Everyone:

All infants who are antigen positive or have a positive DAT need follow up blood work after they are discharged from the hospital. The Allo Hope Foundation has made a helpful printable packet with all of the tests, normal lab values, and a place where you can fill in your baby's results. Get your copy here. Your baby can become anemic later, even if s/he wasn't anemic in the hospital. Weekly follow up blood work is vital until the baby's hemoglobin/hematocrit are going up consistently without a blood transfusion.

Be aware:

After being discharged from the hospital parents and doctors still need to keep a close eye on babies with HDFN, especially in the days and weeks after being released. Since our babies are transferred from MFM to neonatologist to pediatrician it is common for information to fall through the cracks along the way. It is usually up to the parents to make sure that their baby is getting weekly blood tests to monitor for delayed onset anemia. These blood tests should check the baby's hematocrit/hemoglobin and retic. Once the baby’s hct/hgb are stable or rising for two consecutive weeks, you can stop blood tests and the baby is cleared of HDFN.

HDFN can also cause problems like weakened tooth enamel, thrombocytopenia and neutropenia.

Silver Lining:

Baby snuggles! Usually around 12-15 weeks your baby will be cleared and will have beaten HDFN forever! Good job advocating for your baby. You made it!
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