When a patient who has a preexisting medical illness seeks prenatal care, the obstetrician asks herself (himself) 2 questions:
• What impact will the illness have on the pregnancy?
• What impact will the pregnancy have on the illness?
Depression is both a pregnancy-associated and pregnancy-independent illness, which, in the setting of a pregnant woman who has a depressive disorder, makes these questions particularly difficult to answer. In such a case, coordination of care with a mental health provider is essential.
Awareness of the obstetrical complications associated with depression during pregnancy, as well as their implications for the future health of the mother–infant dyad, is important for the entire care team. This article reviews the associations and interconnectedness of depression with complications of pregnancy, childbirth, and the neonatal period.
Diagnosis of depression during prenatal care
The American College of Obstetricians and Gynecologists (ACOG) states that evidence is insufficient to support a recommendation for universal screening for depression among prenatal patients, although such screening should be considered.1 There is considerable variability among obstetrical providers regarding the practice of depression screening; tools to be used if such screening is done; and screening frequency through the pregnancy.
Discernment of depression is difficult. Many somatic symptoms of depression overlap with common prenatal complaints and, consequentially, can be overlooked. Among a sample of 700 pregnant women, for example, 56% complained of lack of energy; 19%, of insomnia; and 19%, of appetite changes.2 Weight change, of course, is universal.
The 10-question self-rating Edinburgh Postnatal Depression Scale has been validated for use during pregnancy and postnatally. This screening instrument can be helpful for differentiating purely physical complaints from mental distress due to depressive symptoms.2,3
When an obstetrical provider suspects a depressive disorder, or one has been diagnosed, she (he) faces the problem of what to do with that information. Women of low socioeconomic status and victims of domestic violence are at increased risk of depression during pregnancy, but barriers to appropriate referral can seem nearly insurmountable because they lack insurance and social support.4-9
In addition, within the setting of numerous tasks that need attending during the relatively short prenatal period, it is common for women newly given a diagnosis of depression to fail to follow up on a referral to a mental health provider.
Although most providers will “check in” with a depressed or at-risk patient at each prenatal visit about her mood, any effort at follow-up can be overshadowed by tangible physical concerns, such as preterm contractions, fetal growth restriction, and coordination of routine testing that has been delayed because of scant prenatal care. All these physical concerns and circumstances of care are associated with maternal depression, as we will discuss.
Preterm labor and birth
Preterm labor is defined as uterine contractions that lead to cervical change before 37 weeks gestational age. Preterm labor increases the risk of preterm birth; preterm labor precedes 50% of preterm births. Preterm birth is the leading cause of neonatal mortality in the United States, and rates of morbidity and mortality increase as gestational age decreases.10 Common neonatal complications related to prematurity are shown in the Figure.11
Women who suffer from depression have an increased risk of preterm labor and preterm birth, as many studies of treated and untreated depressed pregnant women have shown.12-20 The causative mechanism is unknown; it has been proposed that the increase in maternal cortisol production associated with depression and distress triggers overproduction of placental cortisol releasing hormone, which is thought to be involved in initiation of parturition.21,22 Depression also is associated with other risk factors for preterm birth, such as low socioeconomic status, substance use, and smoking.
Intrauterine growth restriction
Women who have depression during pregnancy have an increased risk of intrauterine growth restriction (IUGR), which leads to delivery of an infant who is small for gestational age (SGA) or of low birth weight (LBW) (weighing <2,500 g at birth), or both.23 Again, the basis of the association between depression and IUGR and SGA is unknown; it is theorized that increased levels of cortisol and catecholamines associated with maternal distress might, by increasing blood pressure and inducing vasoconstriction, cause placental hypoperfusion.24,25
It also is possible that the association of depression with other risk factors for IUGR, such as smoking, substance use, obesity, and poor prenatal care, puts the infants of depressed women at risk of growth restriction.26 Several large-scale studies showed that the association between LBW and depression is lost when smoking and substance use are accounted for; other studies, however, found a persistent association in untreated depressed women when smokers, substance users, and drinkers were excluded.17,26,27