Treating Medical Illness in Pregnant Women: 10 Guidelines for Clinicians

Most health care providers err on the side of caution when it comes to prescribing drugs or diagnostic tests for pregnant women.

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By  Stuart Qualtrough Published  April 18, 2005

Treating the pregnant woman|~||~||~|Most health care providers err on the side of caution when it comes to prescribing drugs or diagnostic tests for pregnant women. Their concern is understandable. Indeed there are drugs that can cause birth defects and other problems for a mother and the embryo or fetus within her. But aside from a few glaring exceptions, more harm is generally caused by withholding treatment from pregnant women than by giving it.

“An important measure of a health care is how it takes care of expectant mothers,” says Raymond Powrie, MD, an associate professor of medicine at Brown University and the Women and Infants Hospital. Powrie has lectured on approaches to treating medical illness in pregnant women all over the world, including Dubai. Here he presents ten guidelines for the care of these women. “Fetal well-being is dependent on the health of the mother. We have a belief that the needs of the mother and infant are at odds with each other, but in fact, they overlap,” he said.

1.Remember, women with medical problems can and do get pregnant.

It is best to discuss the impact of the disease and its treatment before pregnancy occurs. Diabetes, asthma, seizures, hypertension, cardiac disease, and taking anticoagulants all can affect a pregnancy. A woman who receives the appropriate treatment has a much better chance of having a healthy pregnancy and delivering a healthy baby than one who does not.

In women with diabetes, for example, poor glycemic control at the time of conception correlates with an increased risk of miscarriage and congenital abnormalities. Specifically HbA1c greater than 8.5 percent correlates with a 25 percent risk of losing the fetus or having a child born with birth defects.

But preconception care can make a big difference. In a 2001 study published in the international medical journal QJM, researchers found that just 2.1 percent of the women who received preconception care had babies with anomalies, versus 6.5 percent of those who did not receive such care. The findings of the meta-analysis of 14 studies underscore the importance of helping women to achieve adequate glycemic control before they become pregnant.

2.In general, it is more harmful to withhold treatment from pregnant women than to give it.

No one wants to take chances with the health of an unborn child. But the fact is, fetal well-being generally depends on maternal well-being. Uninvestigated symptoms lead to the progression of untreated disease. And uncontrolled maternal disease compromises the safety, growth, and development of her fetus—and is often more dangerous than treatment itself. So do not shy away from diagnosing the source of any symptoms experienced by your pregnant patients. By ignoring them—or waiting—you may do more harm than good.

3.Radiologic investigations are generally safe in pregnancy.

Many pregnant women are reluctant to undergo any test that involves radiation. But you can reassure your patients that no single diagnostic imaging procedure results in a radiation dose significant enough to threaten the development of an embryo or fetus.

According to a US national radiation commission, there is no evidence of birth defects resulting from less than five rads, and the possibility of an increase in risk of childhood cancer does not occur until greater than two rads. To put this in perspective, chest x-rays emit less than .001 rads, CT angiograms emit 0.2 to 0.3 rads, and ultrasound and magnetic resonance imaging, angiography and venography emit no rads.

4.Medications in pregnancy should be thought of as “justifiable or not justifiable” rather than “safe or not safe.”

The US Food and Drug Administration (FDA) assigns drugs to pregnancy categories ranging from Category A (“controlled studies show no risk”) to Category X (“contraindicated in pregnancy”).

Although these drug safety classifications are useful, they are not as valuable as a careful consideration of the potential risks of a certain medication and its potential benefits for a given clinical situation. When deciding whether to prescribe a medication to a pregnant woman, it helps to ask yourself the following questions:
·Is the medication necessary, or is the symptom self-limited or amenable to non-pharmacologic management?
·If the medication is not administered, what are the possible outcomes for mother and fetus?
·What data are available on the safety of this medication in pregnancy, and is there a similar drug with a better safety profile that could be used instead?
·How does the patient’s (and the clinician’s) value system affect decisions about using medication in pregnancy?

When prescribing medication for pregnancy women, just remember:
·The first trimester is a period of increased risk and warrants special consideration.
·No drug should be used in pregnancy without a reasonable indication.
·Avoid using newly introduced medications (many important drug toxicities have been picked up in post-marketing surveillance).

And in general, remember to avoid the following medications: tetracyclines, ACE inhibitors, angiotensin receptor blockers, isotretinoin, and fluoroquinolones.

5.Most pregnant women hate taking pills.

Although compliance can be an issue for any patient, there is perhaps no time when a patient is so reluctant to take a meidcation as during a pregnancy. Concerns from friends, family, and even the pharmacist may lead a patient to not take a prescribed medication. It is very important that every prescription warrants a careful discussion of risks and benefits. An open and honest environment where the woman can discuss freely her concerns and fears is the one most likely to lead to compliance.

6.Pregnancy is associated with significant physiologic changes, but is not a disease state.

Although medical illness in pregnancy may lead to increased anxiety on the part of a provider, we should all be careful not to treat the woman as if her pregnancy is a disease state. Women with medical illness deserve to experience some of the joys of pregnancy as much as any woman. While pregnancy is not a disease state, it is associated with some physiologic changes that may impact upon their disease. First, there is an increased cardiac output and blood volume (blood volume rises to 150 percent of normal by 28 weeks of gestation). Second the partial pressure of oxygen (pao2) increases to 90-100 mmhg, and partial pressure of carbon dioxide (paco2) decreases to 28-32 mmhg. Pregnant women also undergo some significant changes in renal function.

7.Vaginal deliveries are generally safer than cesarean sections, even in women with medical problems.

In general a vaginal delivery is the best route for women with medical illness. Marfan’s syndrome and coarctation of the aorta may be the exceptions, but even in these cases there is no evidence that mode of delivery affects the risk of aortic dissection and rupture. Indications for cesarean delivery in medical patients are “obstetrical.”

8.Care of women with medical illness is best done by a multi-disciplinary team.

Pregnant women with medical illness do best if they are care for by both an experienced obstetrician and a medical specialist. The expertise of both of these individuals is necessary to successfully determine the best care plan for such women and to deal with complications as they arise.

9.Maternal mortality remains a global issue.

Worldwide, 1 in 75 women die with pregnancy. What causes these deaths? Worldwide 24 percent bleed to death, 15 percent are killed by infection, 13 percent have an unsafe abortion, 12 percent die from eclampsia, and 8 percent have an obstructed labor. Other direct causes result in another 8 percent of deaths. The remaining 20 percent are due to indirect causes.

The greatest challenge facing the developing world is providing access to skilled attendants at delivery. Progress is being made, however, in preventing pre-eclampsia-related deaths with the use of magnesium to prevent seizures.

10.Mother-to-child transmission of HIV may be prevented by simple interventions.

In the U.S., maternal-to-child transmission (MTCT) of HIV has decreased from 25 percent to less than 2 percent over the past decade through widespread screening of pregnant women and the use of antiretroviral therapy. Prevention regimens include:
·Antepartum, intrapartum, and postpartum AZT
·Elective “bloodless” cesarean delivery reduces the rate to 12 percent.
·Highly active antiretroviral therapy lowers the rate to less than 1 percent.
·Shorter AZT regimens and two doses of nevirapine lower the rate to 8-12 percent.

Learn More

Dr. Powrie recommends the following resources for help assessing individual drugs:

Medications in Pregnancy and Lactation, by G.S. Briggs, R. Freeman and S. Yaffe.
Shepard’s Catalog of Teratogenic Agents, by Thomas H. Shepard
Handbook for Prescribing Medications in Pregnancy, by D.R. Coustan and T.K. Mochizuli
Effects of Medications on the Fetus and Nursing Infant: A Handbook for Health Care Professionals, by J.M. Friedman and J.E. Polifka
Medications & Mother’s Milk: A Manual of Lactational Pharmacology, by Thomas Hale.

This article is provided courtesy of Harvard Medical International.
© 2005 President and Fellows of Harvard College


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