Research paperProlactin, a potential mediator of reduced social interactive behavior in newborn infants following maternal perinatal depressive symptoms
Introduction
Pregnant women exposed to stressful life events, such as domestic affairs, financial or relational problems, and serious illness, are particularly vulnerable to depressive symptoms. Prenatal maternal depression has been a significant public health concern, affecting about 10–25% of women (Teixeira et al., 2009). The symptoms of prenatal maternal depression can continue into the postpartum period (Vesga-Lopez et al., 2008). The newborn period is one that is particularly vulnerable for both mothers and their infants, as maternal perinatal depressive symptoms can impair a mother's ability to respond timely to her infant's cues and to engage in sensitive and passionate interactions with her infant that are associated with optimal newborn neurobehavioral development. Increasing evidence suggests that maternal depression results in newborn behavior disorders, such as attentional, emotional and behavioral problems, which would later be noted in adolescence and adulthood (Feldman et al., 2009). For example, maternal depression has also been related to less responsiveness to stimulation in the neonate (Smith et al., 2011). However, the mechanism underlying newborn behavior disorders resulting from maternal perinatal depressive symptoms remains unclear.
It is generally believed that impaired maternal behavior is responsible for newborn behavioral disorders. While maternal depression may be a proximal cause of impaired maternal behavior (Murgatroyd and Nephew, 2013, Smith et al., 2004), neuroendocrine hormone may exert distal influences on maternal behavior and parenting capacity. The neuropeptide prolactin (PRL) plays a crucial role in the initiation and maintenance of maternal behavior (Larsen and Grattan, 2012), whereas blocking PRL secretion with bromocriptine significantly delays the onset of maternal behavior and impairs parenting capability. Administration of prolactin to nulliparous rats significantly promotes the rapid onset of maternal behavior (Bridges and Ronsheim, 1990). In addition, PRL is implicated in the etiology of mood disorders in women, especially for symptoms of depression (Sjoeholm et al., 2011). Compared to non-depressed controls, the depressed patients showed lower levels of plasma and salivary PRL (Faron-Gorecka et al., 2013; Lykouras et al., 2011). Serum PRL concentration is related to severity of depressive symptoms in women (Slopien et al., 2015). Therefore, prenatal maternal depression results in decreased maternal peripheral PRL accompanied by impaired maternal parenting capability and mother-infant relationship (Grattan and Kokay, 2008).
Moreover, increased maternal peripheral PRL concentration during pregnancy may help attenuate the potentially harmful effects of overexpression of maternal cortisol due to prenatal depression on fetal development. Prenatal maternal depression is associated with hyperactivity of the HPA axis and increased cortisol is a product of this alteration of the HPA axis. Field et al. (2006) found that depressed pregnant women had elevated prenatal cortisol levels mediating the effects of depression on fetal brain development, activity, and growth delays. PRL is often regarded as a ‘‘stress hormone’’ because various stressors stimulate its secretion from the adenohypophysis into peripheral circulation (Torner et al., 2002). The increased PRL is referred to as an adaptation to stress (Torner et al., 2004) and attenuates neuronal stress circuitries (Donner et al., 2007). Thus, PRL mediates the suppression of HPA axis hyperactivity following stress exposure (Torner et al., 2002), implying that PRL inhibits the overexpression of cortisol. Otherwise, the decreased maternal peripheral PRL following prenatal depression is associated with increased maternal and neonatal cortisol concentrations linked with newborn behavioral disorders. Furthermore, peripheral PRL concentration may be implicated in impaired social behavior following chronic social stress. For example, an animal study reported that the offspring of dams exposed to chronic social stress exhibited impaired social behavior accompanied by decreased basal concentrations of plasma prolactin (Babb et al., 2014). However, the above study demonstrated that impaired social behavior in the offspring was associated with their own decreased peripheral prolactin levels. Additionally, there are few clinical studies on the subject. Less is known whether maternal peripheral prolactin concentration is associated with newborn behavioral disorders following maternal perinatal depressive symptoms.
There is a need to develop an effective, easily implemented intervention to ameliorate newborn behavior disorder resulting from maternal perinatal depressive symptoms. The Newborn Behavioral Observations (NBO) system, designed to enhance positive interactions between mothers and their infants and help improve mothers’ parenting capacities and perceived confidence (McManus and Nugent, 2014), provides clinicians a short, flexible, and cost-effective intervention. It has been successfully used to reduce symptoms of postpartum maternal depression. Considering NBO as an infant-centered relationship-based tool, NBO has the potential to be an intervention target for moderating newborn social behavior disorder following maternal perinatal depressive symptoms.
The present study aimed to determine whether maternal peripheral prolactin concentration is associated with newborn behavioral disorders following maternal perinatal depressive symptoms, and further to explore the efficacy of the NBO system in enhancing positive interactions between mothers and their infants and thus improving newborn social interactive behavior.
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Sample
The subjects were recruited from the hospitalized pregnant women waiting for delivery from the department of gynecology and obstetrics of the first affiliated hospital, medical school of Xi'an Jiao tong university between January 2014 and August 2015. In order to be eligible for this study, pregnant women had to be 18 years of age or older, within 37–42 weeks of gestation, and expecting to deliver a single infant. An additional inclusion criterion was the ability to respond to questionnaires in
Demographic characteristics in pregnant women
The characteristics of pregnant women in the depression group did not differ from that in the control group in terms of demographic variables at baseline (p>0.05) (Table 1).
The impact of maternal perinatal depressive symptoms on maternal care
Within 2 weeks postpartum, mothers were asked to fill out the MAI to measure mother-newborn relationship and maternal care. The MAI scores for mothers in the depression group were lower than that of mothers in the normal group (p<0.05) (Table 2).
The impact of maternal perinatal depressive symptoms on neonatal neurobehavioral development
Within 2 weeks postpartum, the NBAS was used to measure neonatal neurobehavioral
Discussion
The present study addressed the neurobehavioral effects of maternal perinatal depressive symptoms on newborns. The results of the current study indicated that newborns of mothers exposed to maternal perinatal depressive symptoms displayed decreases in social interactive items of the NBAS, and there was no association between prenatal maternal depression and the other newborn behavioral items of the NBAS, such as habituation items, reflexes and motor items, state changes and so on. Among the
Declaration of interest
The authors declared no potential conflicts of interest.
Acknowledgments
We would like to thank Aristide Black of the Western Washington University in Bellingham for his help in polishing this manuscript. The work was funded by the science and technology overall planning and innovation project of Shaanxi Province in China (No. 2013KTCQ03-03).
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