Blood Incompatibilities
Blood Incompatibilities
Erythroblastosis Fetalis (EBF)
EBF is the result of blood incompatibility between the mother and her fetus. Understanding how the negative and positive blood incompatibility occurs can be confusing, but here goes.
When the mom’s blood type is negative and the baby’s father’s type is positive, the baby has a 50/ 50 chance of being positive too. Being positive is what causes the problem between mom and baby. The mother’s body normally views the baby as a friendly, harmless parasite. In the Rh negative mom whose baby is Rh positive, the mother’s body views the fetal blood cells as dangerous intruders and takes action. Mom becomes sensitized and develops antibodies (weapons) to destroy the red blood cells in the baby. As the red blood cells are being destroyed, the baby becomes anemic. More problems develop as the baby tries compensating for the anemia. In severe cases, the fetal heart and liver can fail from trying to keep up, although with current treatment 70 percent of even severely affected babies survive.
A Stitch in Time
Prevention is always the best approach to any problem. This is no exception. Once the mother is sensitized, the sensitivity is lifelong and irreversible. It doesn’t help to lock the barn door after the horse has escaped.
Blood typing, Rh determination, and antibody screening are routinely done at the first prenatal visit. All Rh negative mothers have the antibody screen repeated a t 28 weeks of pregnancy. If there are no antibodies to indicate she’s sensitized, a prophylactic injection of Rh Immune Globulin (RhIG) should be given. After delivery, if the baby’s blood type is positive, another injection of RhIG is given within 72 hours, locking the barn door to sensitization. Even if you’re having a tubal ligation, you need RhIG because occasionally tubal ligation fails, or at a later time you might want your tubes reconnected.
Other Indications for RhIG
- Spontaneous abortion (miscarriage) occurring more than 6 weeks after the last menstrual period.
- Induced abortion
- Ectopic pregnancy
- After amniocentesis
There’s always great optimism that EBF will be wiped out in our lifetimes. Do your part; there are always inadvertent slipups. If any of the above situations occur, remind your doctor to order the RhIG injection. Don’t assume you don’t need it – you do.
ABO Incompatibility
Occasionally, blood incompatibility can result when mom has type O and baby has either AB, A, or B type blood. Only 2 percent of births are affected by ABO incompatibility. This type of EBF is different from the Rh-problem. ABO isn’t as serious and doesn’t become more severe with each pregnancy. The baby doesn’t die before birth, and the sophisticated technology, such as amniocentesis and ultrasound, isn’t necessary. Preterm delivery isn’t necessary. ABO incompatibility is more a pediatric disease than an obstetrical one and can usually be treated with little difficulty after the baby is born.
The Overdue Blues-Postdates Pregnancy
You’re now 2 weeks past your due date and officially considered postdates by your doctor. You’re afraid to be seen in public because you’re tired of people asking “Haven’t you had that baby yet?” You stop answering the phone because your mother calls every 3 hours to ask “Is anything happening?” You’ve stopped speaking to your husband, your doctor, and the rest of the world. You don’t want to be pregnant anymore. You want your doctor to do something! You may be miserable, but your doctor isn’t having any fun either. She has to worry about your “aging” placenta providing enough oxygen and nutrients to your baby. Your doctor has to weigh many factors in order to make the appropriate decision in your particular case. If your actual due date is really uncertain, add more gray hairs.
The state of your cervix is usually the critical factor in whether or not labor can be induced. With an unripe cervix, some doctors prefer to leave Mother Nature alone if the fetal well-being tests are reassuring, the baby is growing appropriately, and there’s an adequate amount of amniotic fluid. Some obstetricians start fetal testing at 41 weeks.
The more unripe the cervix, the less chance of a successful induction of labor. There are no guarantees the oxytocin will work. In some cases with an unripe cervix, doctors try the serial induction technique: The first day is spent just trying to ripen the cervix, another day is spent “priming” the uterus, and on the third day efforts are made to establish true labor sometimes it works, sometimes not.
If your cervix is ripe and ready to go, most doctors feel comfortable inducing labor. Everybody can breathe a sigh of relief. If you and your doctor opt for inducing labor, skip to the induction section-your prayers have been answered.