EXPERT ANALYSIS FROM DPSG-NA 2017
WASHINGTON (FRONTLINE MEDICAL NEWS) – George R. Saade, MD, wants to see a Time magazine cover story like the 2010 feature titled, “How the first 9 months shape the rest of your life” – except this new story would read “How the first 9 months shape the rest of the mother’s life.”
It’s time, he says, that pregnancy truly be appreciated as a “window to future health” for the mother as well as for the baby, and that the term “maternal care” replaces prenatal care. “How many of your [primary care] providers have asked you if you’ve had any pregnancies and if any of your pregnancies were complicated by hypertension, preterm delivery, growth restriction, or gestational diabetes?” Dr. Saade asked at the biennial meeting of the Diabetes in Pregnancy Study Group of North America.
“It’s better than before, but not good enough … Checking with patients 6 weeks postpartum is not enough” to prevent long-term metabolic and cardiovascular disorders, he said. “We need regular screening of women.”
The relationship between gestational diabetes (GDM) and subsequent type 2 diabetes, demonstrated several decades ago, offered the “first evidence that pregnancy is a window to future health,” and evidence of the relationship continues to grow. “We know today that there is no other predictive marker of type 2 diabetes that is better and stronger than gestational diabetes,” said Dr. Saade, chief of obstetrics and maternal-fetal medicine at the University of Texas Medical Branch, Galveston.
GDM has also recently been shown to elevate cardiovascular risk independent of its association with type 2 diabetes and metabolic disease.
And similarly, there is now an incontrovertible body of evidence that women who have had preeclampsia are at significantly higher risk of developing hypertension, stroke, and ischemic heart disease later in life than are women who have not have preeclampsia, Dr. Saade said.
Layered evidence
The study that first caught Dr. Saade’s attention was a large Norwegian population-based study published in 2001 that looked at maternal mortality up to 25 years after pregnancy. Women who had preeclampsia had a 1.2-fold higher long-term risk of death from cardiovascular diseases, cancer, and stroke – and women with a history of both preeclampsia and a preterm delivery had a 2.71-fold higher risk – than that of women without such history.
Looking at cardiovascular causes of death specifically, the risk among women with both preeclampsia and preterm delivery was 8.12-fold higher than in women who did not have preeclampsia.
Since then, studies and reviews conducted in the United States and Europe have shown that a history of preeclampsia doubles the risk of developing cardiovascular disease, more than triples the risk of later hypertension, and also increases the risk of stroke, though more moderately.
Recently, Dr. Saade said, researchers have also begun reporting subclinical cardiac abnormalities in women with a history of preeclampsia. A study of 107 women with preeclampsia and 41 women with uneventful pregnancies found that the prevalence of subclinical heart failure (heart failure Stage B) was approximately 3.5% higher in the short term in the preeclampsia group. The women underwent regular cardiac ultrasound and other cardiovascular risk assessment tests 4-10 years postpartum ( Ultrasound Obstet Gynecol. 2017;49[1]:143-9 ).
Preterm delivery and small for gestational age have also been associated with increased risk of ischemic heart disease and other cardiovascular events later in life. And gestational hypertension, research has shown, is a clear risk factor for later hypertension. “We always think of preeclampsia as a different disease, but as far as long-term health is concerned, it doesn’t matter if a woman had preeclampsia or gestational hypertension; she’s still at [greater] risk for hypertension later,” Dr. Saade said.
“And we don’t have to wait 30 years to see evidence” of the association between pregnancy complications and adverse cardiovascular outcomes, he emphasized. A recent retrospective cohort study of more than 300,000 women in Florida showed that women who experienced a maternal placental syndrome during their first pregnancy were at higher risk of subsequent cardiovascular disease during just 5 years of follow-up ( Am J Obstet Gynecol. 2016;215[4]:484.e1-14 ).
Into practice
Regular screening of women whose pregnancies were complicated by conditions associated with long-term health risks “need not be that sophisticated,” Dr. Saade said. Measurement of blood pressure, waist circumference, fasting lipid profile, and fasting glucose is often enough for basic maternal health surveillance, he said.
Dr. Saade said he and some other experts in the field are recommending yearly follow-up for patients who’ve had preeclampsia and other complications. Among the other experts urging early heart disease risk screening is Graeme N. Smith, MD, PhD, an ob.gyn in Ontario who has developed surveillance protocols, follow-up forms, and risk prediction tools for use in a maternal health clinic he established at Kingston General Hospital, Queens University. At the meeting, Dr. Saade encouraged the audience to access Dr. Smith’s resources.
The American Heart Association, in its 2011 guidelines for cardiovascular disease prevention in women, includes pregnancy risks factors (specifically a history of preeclampsia, gestational diabetes, or pregnancy-induced hypertension) as part of its list of major factors for use in risk assessment ( Circulation. 2011;123:1243-62 ).
But as Erica P. Gunderson, PhD, MPH, of Kaiser Permanente Northern California’s division of research, pointed out during another presentation at the meeting, there is more work to be done. Reproductive history is not included in existing disease prediction or risk stratification models for atherosclerotic cardiovascular disease, making it hard at this point to devise specific screening protocols and schedules, especially when it comes to a history of GDM, she said.
“We need more coordinated systems, surveillance in younger women, and some prediction models so that we can know who is at highest risk and needs more surveillance,” she said.
The AHA’s inclusion of GDM history is based on its strong link to overt diabetes, but recent evidence has shown that a history of GDM can independently elevate cardiovascular risk, she noted. Research from the Nurses Health Study II cohort, for instance, found a 30% higher relative risk of cardiovascular events (myocardial infarction and stroke) in women with a history of GDM without progression to diabetes, compared with women who did not have GDM or diabetes ( JAMA Intern Med. 2017;177[12]:1735-42 ).
Dr. Gunderson has also found through analyses of the Coronary Artery Risk Development in Young Adults study data that women who had GDM but did not go on to develop overt diabetes or impaired glycemia had greater carotid intima media thickness many years post delivery than did women without a history of gestational diabetes ( J Am Heart Assoc. 2014;3[2]:e000490 ).
In some models, she has written, this difference in carotid intima media thickness could represent 3-5 years of greater vascular aging for women with previous gestational diabetes and no apparent metabolic dysfunction outside of pregnancy ( JAMA Intern Med. 2017;177[12]:1742-4 ).
There’s a question, she and Dr. Saade both noted, of whether pregnancies unmask previous dispositions to cardiovascular disease or whether pregnancy complications more directly drive adverse long-term outcomes. There is evidence that disorders such as GDM, Dr. Gunderson said, are superimposed on already altered metabolism. But at this time, Dr. Saade said, it appears that “the answer is both.”
According to Dr. Saade, at least three studies are currently following women prospectively to learn more about pregnancy as a window to future cardiovascular health. One of them is the National Institute of Child Health and Human Development’s Nulliparous Pregnancy Outcomes Study–Monitoring Mothers-to-Be Heart Health Study; some data from this study will be presented soon, he said.
Both Dr. Saade and Dr. Gunderson reported in their presentations that they had no disclosures.
