Identify Patients at Risk Early

Studies show, for instance, that women with mild hypertension before conception or early in pregnancy have a 15% rate of preeclampsia, whereas women with severe prepregnancy hypertension have a nearly 50% risk.

In all cases, women with chronic hypertension or diabetes should have their blood pressure and glucose levels optimized before conception, and then controlled throughout their pregnancy.

When assisted reproductive technology is planned, a discussion about the increased risk for preeclampsia that is caused by donated gametes is important, because donor insemination or the use of donated oocytes affects the maternal-fetal immune interaction and increases the risk of preeclampsia to as much as 35%.

Because multifetal gestation is more common with ART than with natural birth and is another risk factor for preeclampsia, this patient's overall risk can also be minimized by reducing the number of transferred embryos and by avoiding hyperstimulation when ovulation induction is required.

Just as in the case of the younger woman, unfortunately, we have little if anything else to offer this patient for the prevention of preeclampsia.

These women can be offered calcium, however. A recent review by the Food and Drug Administration concluded that any benefit with respect to preeclampsia is inconclusive and “unlikely” (Nutr. Rev. 2007;65:78-87).

However, in a 2007 Cochrane review of 12 clinical studies, calcium supplementation was associated with a reduction in the rate of preeclampsia, particularly in populations at high risk and in those with diets deficient in calcium (BJOG 2007;114:933-43).

Management should include a baseline metabolic profile and complete blood count, as well as baseline urinalysis; this information can be helpful if later laboratory studies are needed to assess the function of organ systems likely to be affected by preeclampsia.

Serial ultrasonography as well as uterine Doppler studies at 18-20 weeks should also be employed. The Doppler studies are a useful tool for assessing the velocity of the uterine artery blood flow.

An increased resistance index and/or the presence of uterine artery diastolic notching suggests an increased risk of preeclampsia (as much as a sixfold increased risk) and the need for more vigilant monitoring and care.

A woman who developed severe preeclampsia at 26 weeks' gestation in her first pregnancy. She wants a child but is afraid—terribly and understandably frightened—of a second pregnancy because her first baby was born prematurely and died after about 100 days in the NICU.

We can and should reassure this patient that her loss does not mean she should forego becoming pregnant again, and that with proper monitoring, she has a significant chance of having a healthy baby.

A woman's risk of preeclampsia recurrence will depend on whether or not she has any preexisting risk factors, as well as the gestational age at the time of onset of preeclampsia in her first pregnancy.

The reported rate of recurrent preeclampsia ranges from 11.5% to 65%, with the highest rates being reported in women whose previous preeclampsia occurred in the second trimester. This patient's risk of recurrent preeclampsia is about 50%.

In general, recurrent preeclampsia is more likely to be severe and to develop preterm than is first-time preeclampsia. We can reassure this patient, however, that an early onset of preeclampsia in the first pregnancy does not necessarily mean that the disorder will have an early onset in the second pregnancy.

In a study published in 1991, among women with previous preeclampsia in the second trimester, preeclampsia recurred in the second trimester in 21%, at 28-36 weeks in 21%, and at term in 23% (Am. J. Obstet. Gynecol. 1991;165:1408-12).

Women with a history of eclampsia have a rate of recurrence of 1%-2% and a rate of subsequent preeclampsia of 22%-35%. Women with a history of HELLP (hemolysis, elevated liver enzymes, and low platelet count) syndrome have a rate of preeclampsia in subsequent pregnancies of 16%-52% and, according to the most reliable data, a rate of recurrent HELLP syndrome of less than 5%.

Management for this patient ideally begins before conception, with an extensive evaluation and an in-depth history to uncover preexisting risk factors and/or medical conditions associated with the disorder.

This will allow proper counseling about the magnitude of risk for preeclampsia recurrence, and will guide you as you manage the pregnancy. (See box, bottom left.)

Knowing when she developed preeclampsia is important, as are details about maternal complications such as HELLP (hemolysis, elevated liver enzymes, and low platelet count) syndrome, pulmonary edema, or renal failure, for instance; about fetal complications, such as fetal growth restriction; and about previous laboratory test results, as well as placental pathology.