What to expect when you're expecting (21 page)

Incompetent cervix.
The risk of premature delivery as a result of an incompetent cervix—in which a weak cervix opens early (and, unfortunately, can be suspected only after a woman has experienced a late miscarriage or premature labor once before)—can possibly be reduced by suturing the cervix closed and/or by closely monitoring the length of the cervix via ultrasound (see
page 45
for more information).

History of premature deliveries.
Your chances of premature delivery are higher if you’ve had one in the past. If you’ve had a prior preterm labor and delivery, your practitioner may prescribe progesterone during the second and third trimesters of this pregnancy to avoid a repeat preterm birth.

The following risk factors aren’t controllable, but in some cases they can be somewhat modified. In others, knowing they exist can help you and your practitioner best manage the risks, as well as greatly improve the outcome if an early birth becomes inevitable.

Multiples.
Women carrying more than one fetus deliver an average of three weeks early (though it has been suggested that full term for twins is actually 37 weeks, which might mean that three weeks early isn’t early at all). Good prenatal care, optimal nutrition, and the elimination of other risk factors, along with more time spent resting and restriction of activity as needed in the last trimester, may help prevent a too-early birth. See
Chapter 16
for more information.

Premature cervical effacement and dilation.
In some women, for reasons unknown and apparently unrelated to an incompetent cervix, the cervix begins to thin out and open up early. Recent research suggests that at least some of this early effacement and dilation may be related to a shorter-than-normal cervix. A routine ultrasound of the cervix midpregnancy uncovers which women are at high risk.

Pregnancy complications.
Such complications as gestational diabetes, preeclampsia, and excessive amniotic fluid, as well as problems with the placenta, such as placenta previa or placental abruption, can make an early delivery more likely. Managing these conditions as best as possible may prolong pregnancy until term.

Chronic maternal illness.
Chronic conditions, such as high blood pressure; heart, liver, or kidney disease; or diabetes may raise the risk for preterm delivery, but good medical management and self-care may reduce it.

General infections.
Certain infections (some sexually transmitted diseases; urinary, cervical, vaginal, kidney, and amniotic fluid infections. can put a mother-to-be at high risk for preterm labor. When the infection is one that could prove harmful to the fetus, early labor may be the body’s way of attempting to rescue the baby from a dangerous environment. Preventing the infection or promptly treating it may effectively prevent a too-soon birth.

Under age 17.
Teen moms-to-be are often at a higher risk for preterm delivery. Good nutrition and prenatal care can reduce risk by helping to compensate for the fact that both mother and baby are still growing.

You’ll have to be alert for signs of an impending problem in the second or early third trimester: pressure in the lower abdomen, bloody discharge, unusual urinary frequency, or the sensation of a lump in the vagina. If you experience any of these, call your doctor right away.

“My doctor said my blood tests show I am Rh negative. What does that mean for my baby?”

Fortunately, it doesn’t mean much, at least now that both you and your doctor know about it. With this knowledge, simple steps can be taken that will effectively—and completely—protect your baby from Rh incompatibility.

What exactly is Rh incompatibility, and why does your baby need protection from it? A little biology lesson can help clear that up quickly. Each cell in the body has numerous antigens, or antenna-like structures, on its surface. One such antigen is the Rh factor. Everyone inherits blood cells that either have the Rh factor (which makes the person Rh positive) or lack the factor (which makes them Rh negative). In a pregnancy, if the mother’s blood cells do not have the Rh factor (she’s Rh negative) while the fetus’s blood cells—inherited from dad—do have it (making the fetus Rh positive), the mother’s immune system may view the fetus (and its Rh-positive blood cells) as a “foreigner.” In a normal immune response, her system will generate armies of antibodies to attack this foreigner. This is known as Rh incompatibility.

All pregnant women are tested for the Rh factor early in pregnancy, usually at the first prenatal visit. If a woman turns out to be Rh positive, as 85 percent are, the issue of compatibility is moot because whether the fetus is Rh positive or Rh negative, there are no foreign antigens on the fetus’s blood cells to cause the mother’s immune system to mobilize.

When the mother is Rh negative, as you are, the baby’s father is tested to determine whether he is Rh positive or negative. If your spouse turns out to be Rh negative, your fetus will be Rh negative, too (since two “negative” parents can’t make a “positive” baby), which means that your body will not consider it “foreign.” But if your spouse is Rh positive, there’s a significant possibility that your fetus will inherit the Rh factor from him, creating an incompatibility between you and the baby.

This incompatibility is usually not a problem in a first pregnancy. Trouble starts to brew if some of the baby’s blood enters the mother’s circulation during her first pregnancy or delivery (or abortion or miscarriage). The mother’s body, in that natural protective immune response, produces antibodies against the Rh factor. The antibodies themselves are harmless—until she becomes pregnant again with another Rh-positive baby. During the subsequent pregnancy, these new antibodies could potentially cross the placenta into the baby’s circulation and attack the fetal red blood cells, causing very mild (if maternal antibody levels are low) to very serious (if they are high) anemia in the fetus. Only very rarely do these antibodies form in first pregnancies, in reaction to fetal blood leaking back through the placenta into the mother’s circulatory system.

Prevention of the development of antibodies is the key to protecting the fetus when there is Rh incompatibility. Most practitioners use a two-pronged attack. At 28 weeks, an Rh-negative expectant mom is given a vaccine-like
injection of Rh-immune globulin, known as RhoGAM, to prevent the development of antibodies. Another dose is administered within 72 hours after delivery if blood tests show her baby is Rh positive. If the baby is Rh negative, no treatment is required. RhoGAM is also administered after a miscarriage, an ectopic pregnancy, an abortion, chorionic villus sampling (CVS), amniocentesis, vaginal bleeding, or trauma during pregnancy. Giving RhoGAM as needed at these times can head off problems in future pregnancies.

If an Rh-negative woman was not given RhoGAM during her previous pregnancy and tests reveal that she has developed Rh antibodies capable of attacking an Rh-positive fetus, amniocentesis can be used to check the blood type of the fetus. If it is Rh negative, mother and baby have compatible blood types and there’s no cause for concern or treatment. If it is Rh positive, and thus incompatible with the mother’s blood type, the maternal antibody levels are monitored regularly. If the levels become dangerously high, ultrasound tests are done to assess the condition of the fetus. If at any point the safety of the fetus is threatened because hemolytic or Rh disease has developed, a transfusion of Rh-negative blood to the fetus may be necessary.

The use of RhoGAM has greatly reduced the need for transfusions in Rh-incompatible pregnancies to less than 1 percent, and in the future may make this lifesaving procedure a medical miracle of the past.

A similar incompatibility can arise with other factors in the blood, such as the Kell antigen, though these are less common than Rh incompatibility. If the father has the antigen and the mother does not, there is again potential for problems. A standard screening, part of the first routine blood test, looks for the presence of circulating antibodies in the mother’s blood. If these antibodies are found, the father of the baby is tested to see if he is positive, in which case the management is the same as with Rh incompatibility.

“I was vaccinated against rubella as a child, but my prenatal blood test shows my rubella antibody levels are low. Should I be concerned?”

There’s not much cause for concern when it comes to rubella these days, at least in the United States. Not because the illness isn’t still harmful to the unborn (it still can be, particularly in the first trimester; see
page 506
), but because it’s next to impossible to catch it. The CDC considers rubella to be eradicated in the United States, and since most children and adults have been—and will continue to be—vaccinated against rubella, the chances of being exposed to the illness are virtually nil.

Though you won’t be immunized during pregnancy, you will be given a new rubella vaccine right after you deliver, before you even leave the hospital. It’s safe then, even if you’re breastfeeding.

Immunizations in Pregnancy

Since infections of various sorts can cause pregnancy problems, it’s a good idea to take care of all necessary immunizations before conceiving. Most immunizations using live viruses are not recommended during pregnancy, including the MMR (measles, mumps, and rubella) and varicella (chicken pox) vaccines. Other vaccines, according to the CDC, shouldn’t be given routinely but can be given if they’re needed. These include hepatitis A and pneumococcal vaccine. You also can be immunized safely against tetanus, diphtheria, pertussis, and hepatitis B with vaccines containing dead, or nonactive, viruses. In the must-have department: The CDC recommends that every woman who is pregnant during flu season (generally October through April) receive a flu shot.

For more information about which vaccines are safe during pregnancy and which, if any, you may need (particularly if you’ll be traveling to exotic destinations), check with your practitioner.

“I’m about 60 pounds overweight. Does this put me and my baby at higher risk during pregnancy?”

Most overweight—and even obese (defined as someone whose weight is 20 percent or more over her ideal weight)—mothers have completely safe pregnancies and completely healthy babies. Still, obesity always poses extra health risks, and that’s the case during pregnancy, too. Carrying a lot of extra weight while you’re carrying a baby increases the possibility of certain pregnancy complications, including high blood pressure and gestational diabetes. Being overweight poses some practical pregnancy problems, too. It may be tougher to date your pregnancy accurately without an early ultrasound, both because ovulation is often erratic in obese women and because some of the yardsticks practitioners traditionally use to estimate a due date (the height of the fundus, or top of the uterus, the size of the uterus, hearing the heartbeat) may be difficult to read through layers of fat. The padding may also make it impossible for the practitioner to determine a fetus’s size and position (as well as make it harder for you to feel those first kicks). Finally, delivery difficulties can result if the fetus is much larger than average, which is often the case with obese mothers (even among those who don’t overeat during pregnancy, and particularly with those who are diabetic). And if a cesarean delivery is necessary, the over-ample abdomen can complicate both the surgery and recovery from it.

Then there’s the issue of pregnancy comfort, or rather discomfort—and unfortunately, as the pounds multiply, so do those uncomfortable pregnancy symptoms. Extra pounds (whether they’re pounds you already had or pounds you added during pregnancy) can spell extra backache, varicose veins, swelling, heartburn, and more.

Daunted? Don’t be. There’s plenty you and your practitioner can do to minimize the risks to you and your baby and the discomfort for you—it’ll just take some extra effort. On the medical care side, you will probably undergo more testing than the typical low-risk pregnant woman: ultrasound early on to date your pregnancy more accurately, and later to determine the baby’s size and position; at least one glucose tolerance test or screening to determine if you are showing any signs of developing gestational diabetes; and, toward the end of your pregnancy, nonstress and other diagnostic tests to monitor your baby’s condition.

Pregnancy After Gastric Bypass

Double congratulations—you’ve lost a whole lot of weight, and you’re expecting! But as you pat yourself on the back (or the belly), you may also be wondering how having had gastric bypass or lap band surgery will affect your pregnancy. Happily, not that much. Chances are you were advised not to become pregnant for at least the first 12 to 18 months after your surgery—the time of the most drastic weight loss and potential for malnutrition. But once you’ve passed that benchmark, your chances of having a healthy pregnancy and healthy pregnancy outcome are actually even better than they would have been if you hadn’t had the surgery and lost the weight. Still, as you probably know, you’ll have to work extra hard to ensure the healthiest outcome:

Put your weight loss surgeon on your prenatal team. He or she will be best able to advise your ob-gyn or midwife on some of the specific needs of a post–gastric bypass patient.