The postpartum period is a time of major adjustment for new parents. Biological changes in mothers that occur after childbirth are often accompanied by significant changes in family roles and responsibilities as well. Generally, postpartum depression (PPD) is thought to be associated with the drastic changes in hormone levels that occur during and just after pregnancy. Couple that with the daunting challenges associated with caring for a newborn, and the estimated 7 to 13 percent prevalence rate i becomes less surprising. And likely, that number is on the low side because like many mental disorders, PPD is generally under-recognized and under-treated. Recently, disorders during the postpartum period have also been described in new fathers. ii
Congress has taken note of the seriousness of PPD as well. The Affordable Care Act of 2010 specifically mentions the need “to continue activities on postpartum [conditions]…including research to expand the understanding of the causes of, and treatments for, postpartum conditions." iii
Consistent with Congressional interest, NIMH recently convened a workshop to encourage innovative research in PPD and other mood disorders that emerge during and after pregnancy. Participants discussed ways to optimize the use of currently available treatments based on a better understanding of individual differences among women. Studies of these individual differences, based on biomarkers, personal history or clinical features, will pave the path to personalized medicine. Meeting participants also discussed how to align new PPD research approaches with broader NIMH priority areas. These include research on comparative effectiveness, cost effectiveness, and global mental health.
The current recommended treatments for women with PPD generally follow the course for any type of major depressive disorder (MDD) and include medication and psychotherapy. We now know that pregnancy is not protective against mental health disorders, and stopping antidepressants during pregnancy may lead to relapse. iv In addition, a mother’s depression can have physical effects on the fetus. But questions remain about how antidepressants affect a growing fetus or nursing baby. v Many pregnant or postpartum women choose not to take these medications. And although psychotherapy has been shown to be effective, getting access to evidence-based treatment can be difficult. So the need for alternatives, better treatments, and better delivery of services is great.
What new treatments are on the horizon? In preliminary trials, 17-beta estradiol, a form of estrogen, was shown to have a relatively rapid antidepressant effect in women with PPD, faster than typical antidepressant medications like SSRIs, which can take up to 8 weeks to start working. And unlike antidepressants, evidence suggests that the increased levels of estrogen associated with the treatment are not detected in breast milk, and therefore presumably do not pass to the nursing newborn. vi
Another NIMH study is modeling the effects of the normal hormonal changes in pregnancy and the postpartum period in non-pregnant women with a history of PPD, and comparing their progress with healthy volunteers. The study is testing whether hormonal events during the postpartum period trigger mood changes in women with PPD. It will serve as a source of information about both the biology of PPD and the factors that could put a woman at risk for developing it. Both of these studies provide evidence that the change in estrogen levels during the postpartum period may be a primary hormonal trigger for PPD.
Other studies are looking at the pathophysiology of PPD by identifying changes in the pregnant and postpartum brain that may help us better understand the neurochemical vulnerability to this disorder. vii In particular, neurosteroids, some of which are the products of progesterone, have long been suspected as mediators of anxiety and recently have been implicated in PPD. In animal studies, the normal massive increase in neurosteroids during pregnancy and precipitous decline at childbirth is usually compensated by a change in GABA receptors in the cortex of the brain. Mice without this compensatory GABA receptor change manifest many of the features of postpartum depression, including profound deficits in maternal care.
We know that women with a history of depression are at higher risk for PPD. What can we do to prevent it? Prevention is still a “work in progress." For example, current NIMH-funded research is investigating cognitive therapy and exercise programs to prevent PPD in pregnant women who are at high risk for PPD. NIMH is also funding studies to improve screening for PPD, web-based interventions and treatment models that use home visits.
These studies are a good start. But we still have a long way to go in treating and preventing PPD, and understanding its long-term impact on families.
i Gaynes BN, Gavin N, Meltzer-Brody S, Lohr KN, Swinson T, Gartlehner G, Brody S, Miller WC. Perinatal Depression: Prevalence, Screening Accuracy, and Screening Outcomes. Evidence Report/Technology Assessment No. 119. (Prepared by the RTI-University of North Carolina Evidence-based Practice Center, under Contract No. 290-02-0016.) AHRQ Publication No. 05- E006-2. Rockville, MD: Agency for Healthcare Research and Quality. February 2005.
ii Paulson JF, Bazemore SD. Prenatal and postpartum depression in fathers and its association with maternal depression. Journal of the American Medical Association. 2010;303(19):1961-1969.
iii 124 STAT. 344 PUBLIC LAW 111–148—MAR. 23, 2010 SEC. 2952.
iv Cohen LS, Altshuler LL, Harlow BL, Nonacs R, Newport DJ, Viguera AC, Suri R, Burt VK, Hendrick V, Reminick AM, Loughead A, Vitonis AF, Stowe ZN. Relapse of major depression during pregnancy in women who maintain or discontinue antidepressant treatment. Journal of the American Medical Association . 2006 ;295(5):499-507.
v Wisner KL, Sit DKY, Hanusa BH, Moses-Kolko EL, Bogen DL, Hunker DF, Perel JM, Jones-Ivy S, Bodnar LM, Singer LT. Major depression and antidepressant treatment: impact on pregnancy and neonatal outcomes. American Journal of Psychiatry. Online ahead of print March 15, 2009.
vi Perheentupa A, Ruokonen A, Tapanainen JS. Transdermal estradiol treatment suppresses serum gonadotropins during lactation without transfer into breast milk. Fertility and Sterility. 2004 Oct;82(4):903-907.
vii Maguire J, Mody I. GABAAR plasticity during pregnancy: relevance to postpartum depression. Neuron. 2008 Jul 31; 59.