Q: My blood type is negative. I’ve heard this might complicate my pregnancy. What do I need to know?
A: What you’re referring to is your Rhesus type or Rh factor. Two things typically characterize blood type: the letters O, A, B, or AB and positive or negative Rh status. Because a baby’s blood type is a result of both its parent’s blood types, it’s possible for a fetus to have a different blood type from its mother. Differences in letter type rarely cause serious problems. But a difference in Rh factor can create antibodies that cross the placenta and destroy baby’s blood cells, causing severe anemia.
To make these antibodies, the mom must be Rh negative and carry a baby that is Rh positive. In the United States, only about 15 percent of blood types are Rh negative. That’s because Rh is a recessive gene, meaning that if you test negative you must have two copies of the negative gene. If you and your partner are both Rh negative, you cannot have an Rh-positive child. However, if you’re Rh negative and your partner is Rh positive, there’s a good chance your baby will be Rh positive, too.
When an Rh-negative mom carries an Rh-positive baby, there’s a 17 percent risk she’ll create these dangerous antibodies. If she receives a shot of a drug called RhoGAM around 28 weeks and again right after delivery, the risk is reduced to 1 in 1,000. For this reason, your doctor will type your blood early in your pregnancy. If you’re Rh negative and the father is Rh positive, you’ll be given RhoGAM and have a low risk of any related complications.
Itchy and Scratchy
Q: I’m in my 35th week and recently developed a really itchy rash on my belly. I go on daily walks in the woods so I thought it was just poison ivy, even after it spread to my legs, but now it’s so bad I can’t sleep. What’s happening to me?
A: Only a visit to your doctor can give you a diagnosis, but I suspect you have PUPPP (pruritic urticarial papules and plaques of pregnancy), what’s now more often called PEP (polymorphic eruption of pregnancy).
This is the most common itchy rash of pregnancy, affecting about 1 in 160 pregnancies. It develops late in the third trimester, tends to stabilize as the pregnancy progresses, and goes away with delivery. The cause is unknown and no increased risk of other conditions has been found in the mother or her baby as a result.
The rash often starts on the belly with red, itchy, and raised skin. Sometimes tiny blisters are present. In many women, the bumps merge into a larger red area. The face, hands, and feet are rarely involved, but spreading to the legs, buttocks, chest, arms, and back is common.
To treat it, your ob/gyn will likely prescribe a combo of pregnancy-safe antihistamines and steroids. But be sure to see a doctor now—in rare cases, an itchy rash can be a sign of something more serious.
