Findings
Using these criteria, 51% of patients were found to be in the ideal blood pressure category, 85% had ideal total cholesterol, and 56% had ideal BMI.
Blood pressure
“We found that when we analyzed gestational age as a continuous variable, patients with intermediate or poor blood pressure delivered earlier,” says Dr. Eudy. “Having poor blood pressure meant a patient delivered about a week earlier than patients who did not meet the ideal blood pressure marker” (β –0.96, 95% confidence interval [CI] –1.62 to –0.29). Blood pressure did not appear to have an impact on the risk of having a small-for-gestational-age infant. Dr. Eudy notes that increased blood pressure is associated with an increased risk of preterm birth in the general population, “so that was similar in our study as well.”
Cholesterol
The team also found an association between cholesterol and preterm births, although not a link with small-for-gestational-age infants. “Patients who had intermediate or poor total cholesterol preconceptionally had an increased risk of preterm birth,” explains Dr. Eudy (odds ratio [OR] 2.21, 95% CI 1.06–4.62). She adds, “Among general population women with or without lupus, we’ve also seen that association.” Previous limited research suggests this link with spontaneous preterm birth may be potentially mediated via maternal inflammation.1
BMI
The group’s findings surrounding BMI were perhaps the most surprising. No real association was seen for patients who were overweight in terms of preterm birth. Explains Dr. Eudy, “We did see almost a decreased risk for patients who were obese, which was inverse from what we were expecting.” She and her team speculate that one potential mechanism may have been increased care and more targeted interventions provided to such patients.
The team lacked the data to identify whether preterm births were spontaneous or medically indicated, situations with different risk factors. As Dr. Eudy explains, “Indicated preterm birth could be due to such factors as preeclampsia, which goes along with high blood pressure, whereas spontaneous preterm birth can be caused by other risk factors. Unfortunately, we weren’t able to stratify by the indication for preterm birth, which I think could be insightful in understanding this outcome.”
Having an intermediate (overweight) BMI was associated with decreased odds of having a small-for-gestational-age infant (OR 0.26, 95% CI 0.11–0.63, adjusted for race and prednisone use).
Dr. Eudy notes the risk of having a small-for-gestational-age infant may decrease with increasing BMI, because large-for-gestational-age infants are more common with increasing BMI. “I think more work is needed in that particular aspect to see if that association is seen in other cohorts,” she says.
Other potential metrics
In the future, Dr. Eudy would like to see a composite risk score that includes the other four factors highlighted by the AHA: smoking status, fasting glucose, physical activity level and dietary information.5 Dr. Eudy notes that having a poor metric on any of these variables may also increase the risk of preterm birth or small-for-gestational-age infants, given existing data gathered from the general population.
Preconception Counseling
The bottom line is that these cardiovascular factors are worth bringing up with lupus patients considering pregnancy. Rheumatologists can play an important role checking in with patients who may intentionally or accidentally become pregnant to ensure they are as healthy as possible before conception. Although a rheumatologist is unlikely to have primary management of these specific cardiac risk factors, they can play an important role in co-management. Consider introducing a preconception exercise program or other intervention that may improve pregnancy and overall health outcomes.
“When you are counseling a lupus patient prior to becoming pregnant, in addition to thinking about their lupus activity—Is it well controlled? Has it been controlled for the past six months? What medications are they taking?—we also need to think outside lupus for a little bit as well,” says Dr. Eudy. “We need to take into consideration these more traditional risk factors of poor pregnancy outcomes and cardiovascular health to help give a complete idea of their risk factors during pregnancy.”
