More than 50 years of data consolidate the association between pregnancy complications and premature death, but the solutions remain elusive.
Pregnancy complications are linked to later mortality risks, and this link appears to be even stronger in black women, according to more than 50 years of follow-up data from the Collaborative Perinatal Project.
The results add to other studies that detail a connection of decades between conditions like hypertensive disorders of pregnancy, preterm birth and gestational diabetes with adverse outcomes, but the study – released in 1959 – goes a step further, highlighting entrenched racial disparities that have not budged in subsequent years.
“Our findings further convey and support the message that the promotion of healthy longevity must start early, starting with a healthy pregnancy,” commented senior author Cuilin Zhang, MD, PhD (Yong Loo Lin School of Medicine, National University of Singapore). to TCTMD. “This is particularly true given additional data implicating the intergenerational adverse health impacts of common pregnancy complications.”
Natalie Bello, MD, MPH (Smidt Heart Institute, Cedars-Sinai Medical Center, Los Angeles, CA), who was not involved in the analysis, said “it confirms everything we knew.”
Perhaps what is “most disturbing” is that even in the 1950s and 1960s, when women were enrolled in the study, “there were these stark racial disparities in maternal outcomes,” she told TCTMD. “If you look at black women’s hypertension rates, even back then chronic hypertension was twice as common in black women compared to white women. It reinforces what we already knew, and unfortunately, we haven’t made much progress on that.”
More than 50 years of data
For the study, published online last week ahead of print in Circulation, Stefanie N. Hinkle, PhD (University of Pennsylvania, Philadelphia), Zhang and colleagues included 46,551 participants, 45% of whom were black, who had an average duration of 52 years of data between pregnancy and death or censoring. Patients were enrolled in the Collaborative Perinatal Project, which enrolled pregnant women from 12 US centers between 1959 and 1966, and follow-up data were collected through 2016.
Overall, mortality was higher for black participants than for whites (41% vs 37%), as was the incidence of preterm delivery (20% vs 10%).
All-cause mortality over time was associated with the following pregnancy complications after adjusting for age, prepregnancy body mass index, smoking, race and ethnicity, previous pregnancies, marital status, income, education, previous medical conditions, location and year:
- Premature spontaneous labor: HR 1.07 (95% CI 1.03-1.1)
- Premature rupture of membranes: HR 1.23 (95% CI 1.05-1.44)
- Induced labor: HR 1.31 (95% CI 1.03-1.66)
- Antepartum cesarean section vs term delivery: HR 2.09 (95% CI 1.75-2.48)
- Gestational hypertension: HR 1.09 (95% CI 0.97-1.22)
- Pre-eclampsia or eclampsia: HR 1.14 (95% CI 0.99-1.32)
- Pre-eclampsia or superimposed eclampsia: HR 1.32 (95% CI 1.20-1.46)
- Gestational diabetes/impaired glucose tolerance: HR 1.14 (95% CI 1.00-1.30)
There was an interaction between whether patients were black or white in relation to both preterm births (P = 0.009), as well as hypertensive disorders of pregnancy (P = 0.05). In addition, preterm labor was associated with a higher risk of mortality over time for black women (adjusted HR 1.64; 95% CI 1.10-2.46) compared with white women (adjusted HR 1. 29; 95%CI 0.97-1.73).
‘We need to find out why’
O American Congress of Obstetricians and Gynecologists already supports a “warm transfer” of patients with pregnancy complications to cardiology or primary care, depending on the complexity of the case, Bello explained. But what often happens is that, over time, patients get busy, don’t keep up, and end up lost in the system. What can also complicate matters is that many patients who have a problem during pregnancy, such as gestational hypertension, see their symptoms resolve in the postpartum period and assume that the problem has also disappeared.
Bello cited another common situation, where a patient never understood the seriousness of a complication she was experiencing at the time. “They may have been told, but there’s so much going on at the time of birth that it can sometimes get lost in the immediate concerns of ‘How am I doing?’ ‘How’s my baby doing?’ pain and wound care. ,” she said.
“It’s not just cooperation between doctors, nurses, care staff, but we also need to educate patients when they leave the hospital or at the postpartum visit that this is something that requires long-term follow-up and we can modify their risk,” he emphasized. Bello.
However, this gets even more complicated when you consider the racial differences observed in this study. “It is disturbing that we are not making any impact on disparities [and] that they are persisting over time. . . . When we look at the black maternal mortality crisis in this country, obviously it has a long legacy and it’s not going to be fixed overnight, but we really need to start working to reduce it. It’s not enough to just say, ‘Look, here we found that black women are doing worse.’ We need to find out why this occurs and fix them.”
In the future, she would like to see more studies looking at modifying risk factors after adverse pregnancy outcomes, especially with regard to more aggressive lipid lowering and what role antiplatelet agents or vascular modifying drugs may play for some. “We just don’t have the data,” Bello said.
Zhang also said more research is needed in “other race/ethnicity groups, such as Asians and Hispanics, where limited data are available.”