Developed by Canadian researchers, the easily implementable PMH CAREPLAN index “creates a framework for clinically actionable risk stratification that could assist patients and providers in determining an individual’s level of risk for common postpartum mental health disorders and direct them to appropriate intervention,” wrote a group led by Simone N. Vigod, MD, MSc, head of the department of psychiatry at Women’s College Hospital, Toronto, in the British Journal of Psychiatry.
courtesy Women's College Hospital
Dr. Simone Vigod
After giving birth, women are especially vulnerable to major depression, anxiety, PTSD, and obsessive-compulsive disorder, which have a general postpartum prevalence of 7%-20%.
Common PMH disorders are to be distinguished from the more rare but severe PMH disorders such as postpartum psychosis and bipolar disorder, the researchers stressed.
“We know there are interventions that can prevent these disorders, but these seem to work best in people who are at high risk for developing the illnesses, “ Dr. Vigod said. “So, we wanted to be able to determine the level of risk that a person might actually experience them.”
In an ideal world, she continued, physicians might be able to say to a patient: “You have a 50% chance of developing postpartum depression and anxiety, so it may be worth investing your time and resources in a course of preventive psychotherapy.” Or: “You have a 90% chance of developing these disorders, so it might be worth going back on your medications even though you are breastfeeding.” Or: “You have only a 1% chance of developing them, so probably it’s not worthwhile to go back on your medication prophylactically.”
A need for a new assessment tool, akin to the Framingham Risk Score for 10-year cardiovascular events and the FRAX scoring system for 10-year fracture risk, was evident since previous indices based largely on patient self-reporting have had moderate predictive capacity, and have not been adopted in clinical practice, Dr. Vigod and associates noted.
Split-cohort design
Using population-based health administrative data and hospital birth records from Ontario during 2012-2015, Dr. Vigod’s group created and internally validated a predictive model for common PMH disorders in a cohort of 152,362 mothers. They then converted it to a risk index after validation in an additional cohort of 75,772 mothers. The women had delivered live infants during 2012-2014.
A common PMH disorder occurred in 13,608 mothers, while 214,526 were unaffected.
Independently associated PMH variables were many: prenatal care provider, mental health diagnosis history and medications during pregnancy, psychiatric hospital admissions or ED visits, conception type and complications, and apprehension of newborn by child services. Other factors were region of maternal origin, extremes of gestational age at birth, primary maternal language, lactation intention, maternal age, and number of prenatal visits.
Based on a broad span of scores from 0 to 39, 1-year common PMH disorder risk ranged from 1.5% to 40.5%, with an overall 1-year prevalence of 6%, consistent with previous studies. That included 11,262 (5%) mothers with an anxiety or related disorder, 3,392 (1.5%) with a depressive episode, and 1,046 (0.5%) with both. The best trade-off of sensitivity/specificity for risk appeared to be at a screening threshold score of 17 or above.
Risk drivers
PMH-affected mothers were slightly younger than unaffected women (mean age, 29.9 years vs. 30.6 years), more likely to be primiparous (45.2% vs. 42%), and less likely to be recent immigrants (16.7% vs. 27.2%).
They were also more likely to have previously experienced postpartum depression (4.4% vs. 1.4%), any depression (15.3% vs. 4.4%), and any anxiety disorder (13.8% vs. 4.3%).
As to lifestyle, smoking was more common in women with PMH (15.0% vs. 10.2%), as were the use of nonprescribed substances (3% vs. 1.4%) and intimate partner violence in pregnancy (2.7% vs. 1.5%).
In addition, the affected group experienced more pregnancy complications than their unaffected peers (16% vs. 13.9%), preterm birth (8.2% vs. 6.8%), and Apgar scores below 7 at 1 or 5 minutes (10.5% vs. 7.6%).
Low income did not appear to have an impact since just over 20% in either group fell into the lowest neighborhood income quintile.
courtesy Northwestern Medicine
Dr. LaTasha D. Nelson
Commenting on the index but not involved in developing it, LaTasha D. Nelson, MD, an associate professor or medicine and a maternal-fetal medicine specialist at Northwestern Medicine in Chicago, doubted the Canadian model would work as well in the more fragmented U.S. health care system, compared with Canada’s universal model with its large provincial health databases.
She also found the large number of variables and broad score range potentially problematic, especially if the risk threshold is set at less than half the maximum score at 17, at which some low-risk mothers might get screening and perhaps intervention. “Are we going to use up the resources we have for those who might not need help, or are we going to treat someone who really needs it?” she asked.
Another concern is the postpartum timing of assessment. At Dr. Nelson’s center, mothers are checked for mental health at two points during pregnancy and those with higher scores are triaged for further care.
Dr. Nelson was also puzzled by the score-lowering impact of prenatal care given by a nurse practitioner and “other” provider : –5 and –2, respectively, versus +3 for a midwife and +1 for a family doctor. “This may capture more relaxed, easy-going multiparous mothers who felt comfortable turning to an NP,” she said.
It may indeed reflect that the risk level of a person who sees those providers is overall lower, Dr. Vigod agreed. “This is one reason why we would want to see replication of these results in other jurisdictions and by other ways of diagnosis before putting it out into clinical practice.”
As to the score-lowering effect of not speaking English as the primary tongue, Dr. Nelson wondered, “is that because we’re taking better care of mothers who speak the main language and missing those who speak other languages? Are they not getting the same level of interrogation?”
It may be that individuals in these groups were less likely to access mental health care, Dr. Vigod agreed, or it might reflect the so-called healthy immigrant effect or culturally different levels of postpartum support. “It might mean that there are more people who benefit from community-level protective factors in these groups. We know that social support is an important protective factor.”
Despite her reservations about the index, Dr. Nelson said that increasing attention to the pre- and postnatal mental health of mothers is an important part of maternal care. “This is an issue that needs to be recognized.”
The next step, Dr. Vigod said, is to determine whether the index holds up in other populations. “Then, we would want to test it out to see if recommending interventions based on a certain level of risk improves outcomes. At what percentage risk would starting an antidepressant medication result in a reduced risk for postpartum depression or anxiety – 90%, 80%, 70%, or less?”
The study received funding from the Canadian Institutes of Health Research. Data were analyzed by ICES, an independent nonprofit research organization that holds population-based data. Dr. Vigod reported royalties from UpToDate for materials related to depression and pregnancy. Dr. Nelson disclosed no relevant competing interests.