Maternal use of selective serotonin reuptake inhibitors (SSRI) during pregnancy-neonatal outcomes in correlation with placental histopathology

Common mental disorders and perinatal outcomes in Victoria, Australia: A population-based retrospective cohort study

PURPOSE

Common mental disorders (non-psychotic mental health conditions which impact on day-to-day functioning) are increasingly common in childbearing women and may impact significantly on both maternal and neonatal outcomes. Our study examines the associations between common mental disorders and perinatal outcomes.

METHODS

We used routinely collected perinatal data (2009-2016) for this population-based retrospective cohort study (n = 597,522 singleton births). We undertook multiple logistic regression adjusting for key maternal medical conditions and sociodemographic factors to determine associations between maternal common mental disorders and adverse perinatal outcomes with confidence intervals set at 95%.

RESULTS

Women with common mental disorders were more likely to have an induction of labour and caesarean birth, have a postpartum haemorrhage (PPH), and be admitted to the Intensive Care Unit (ICU) than women without common mental disorders. Neonates of women with common mental disorders were more likely to have an Apgar score at five minutes of less than seven (a measure of neonatal wellbeing at birth), be born preterm and low birthweight, be admitted to the Special Care Nursery or Neonatal Intensive Care Unit (SCN/NICU) and have a congenital anomaly than neonates of women without common mental disorders.

CONCLUSION

Common mental disorders during the perinatal period were associated with poorer perinatal outcomes for mothers and their neonates. Strategies that enable early recognition and response to maternal common mental disorders should be developed to mitigate the consequential impact on maternal and infant wellbeing.

Maternal serotonin: implications for the use of selective serotonin reuptake inhibitors during gestation†

Maternal use of antidepressants has increased throughout the last decades; selective serotonin reuptake inhibitors (SSRI) are the most prescribed antidepressants. Despite the widespread use of SSRI by women during reproductive age and pregnant women, an increasing amount of research warns of possible detrimental effects of maternal use of SSRI during pregnancy including low birthweight/small for gestational age and preterm birth. In this review, we revisited the impact of maternal use of SSRI during pregnancy, its impact on serotonin homeostasis in the maternal and fetal circulation and the placenta, and its impact on pregnancy outcomes-particularly intrauterine growth restriction and preterm birth. Maternal use of SSRI increases maternal and fetal serotonin. The increase in maternal circulating serotonin and serotonin signaling likely promotes vasoconstriction of the uterine and placental vascular beds decreasing blood perfusion to the uterus and consequently to the placenta and fetus with potential impact on placental function and fetal development. Several adverse pregnancy outcomes are similar between women, sheep, and rodents (decreased placental size, decreased birthweight, shorter gestation length/preterm birth, neonatal morbidity, and mortality) highlighting the importance of animal studies to assess the impacts of SSRI. Herein, we address the complex interactions between maternal SSRI use during gestation, circulating serotonin, and the regulation of blood perfusion to the uterus and fetoplacental unit, fetal growth, and pregnancy complications.

Profiling placental DNA methylation associated with maternal SSRI treatment during pregnancy

Selective serotonin reuptake inhibitors (SSRIs) for treatment of prenatal maternal depression have been associated with neonatal neurobehavioral disturbances, though the molecular mechanisms remain poorly understood.  In utero exposure to SSRIs may affect DNA methylation (DNAme) in the human placenta, an epigenetic mark that is established during development and is associated with gene expression. Chorionic villus samples from 64 human placentas were profiled with the Illumina MethylationEPIC BeadChip; clinical assessments of maternal mood and SSRI treatment records were collected at multiple time points during pregnancy. Case distribution was 20 SSRI-exposed cases and 44 SSRI non-exposed cases. Maternal depression was defined using a mean maternal Hamilton Depression score > 8 to indicate symptomatic depressed mood ("maternally-depressed"), and we further classified cases into SSRI-exposed, maternally-depressed (n = 14); SSRI-exposed, not maternally-depressed (n = 6); SSRI non-exposed, maternally-depressed (n = 20); and SSRI non-exposed, not maternally-depressed (n = 24). For replication, Illumina 450K DNAme profiles were obtained from 34 additional cases from an independent cohort (n = 17 SSRI-exposed, n = 17 SSRI non-exposed). No CpGs were differentially methylated at FDR < 0.05 comparing SSRI-exposed to non-exposed placentas, in a model adjusted for mean maternal Hamilton Depression score, or in a model restricted to maternally-depressed cases with and without SSRI exposure. However, at a relaxed threshold of FDR < 0.25, five CpGs were differentially methylated (|Δβ| > 0.03) by SSRI exposure status. Four were covered by the replication cohort measured by the 450K array, but none replicated. No CpGs were differentially methylated (FDR < 0.25) comparing maternally depressed to not depressed cases. In sex-stratified analyses for SSRI-exposed versus non-exposed cases (females n = 31; males n = 33), three additional CpGs in females, but none in males, were differentially methylated at the relaxed FDR < 0.25 cut-off. We did not observe large-scale alterations of DNAme in placentas exposed to maternal SSRI treatment, as compared to placentas with no SSRI exposure. We also found no evidence for altered DNAme in maternal depression-exposed versus depression non-exposed placentas. This novel work in a prospectively-recruited cohort with clinician-ascertained SSRI exposure and mood assessments would benefit from future replication.

Fluoxetine-induced perinatal morbidity in a sheep model

Selective serotonin reuptake inhibitors (SSRI) are the most common antidepressants used by pregnant women. However, adverse pregnancy outcomes have been described in women taking SSRI during pregnancy—placental lesions, premature birth, poor neonatal adaptation. We aimed to investigate the effects of fluoxetine (Prozac® most commonly used SSRI) treatment during the last month of gestation on pregnancy complications, placental and neonatal health in a non-depressed sheep model. On day 119 ± 1 postbreeding (experimental day 0; E0) of a 151-day expected gestation, Hampshire ewes were randomly assigned to receive fluoxetine (n = 9 ewes, 15 lambs; daily intravenously treatment with 10 mg/kg on E0 and E1 and 5 mg/kg daily thereafter until parturition) or to a control group (n = 10; 14 lambs; vehicle only). Blood samples from ewes were collected throughout the experimental period and postpartum; blood from lambs were collected postpartum. Analysis of variance was used for statistical analysis. Fluoxetine treatment reduced placentome growth during the last month of pregnancy. Gestation length was decreased by 4.5 days in fluoxetine-treated ewes. Birthweight was reduced in lambs exposed to fluoxetine in utero; weights remained decreased until postnatal day 3. Placentome diameter by birthweight ratio was not different between groups suggesting that the decreased placentome diameter was accompanied by decreased lamb birthweight. During the first week postnatal, lambs exposed to fluoxetine in utero had decreased blood pH and decreased total carbon dioxide, bicarbonate, and base excess and increased lactate (days 3–6), collectively indicative of metabolic acidemia. Additionally, ionized calcium was decreased between postnatal days 0 to 4 in lambs exposed to fluoxetine in utero. Using a non-depressed animal model clearly defines a role for SSRI on the occurrence of perinatal complications and neonatal morbidity. The decreased placentome diameter, shortened gestation, decreased birthweight, decreased calcium levels, and neonatal acidemia suggest the occurrence of intrauterine growth restriction. The persistence of neonatal acidemia for several days postpartum suggests poor neonatal adaptation to extrauterine environment.

Pregnancy Complications and Neonatal Mortality in a Serotonin Transporter Null Mouse Model: Insight Into the Use of Selective Serotonin Reuptake Inhibitor During Pregnancy

Selective serotonin reuptake inhibitors (SSRI) are widely prescribed to pregnant woman. Although some SSRI compounds are known to cause pregnancy loss and fetal malformations, other SSRI continue to be used by pregnant women. However, several studies have associated the use of SSRI with adverse pregnancy outcomes: intrauterine growth restriction, preterm birth, and neonatal morbidity. Nonetheless, interpretation of studies in humans are typically complicated by the adverse pregnancy outcomes caused by depression itself. Therefore, we used a mutant mouse model with genetic ablation of the serotonin transporter, the target site for SSRI, to unravel the role of the serotonin transporter on pregnancy outcomes. The serotonin transporter null mice had increased pregnancy loss (17.5 vs. 0%), decreased number of pups born (6.6 ± 0.2 vs. 7.5 ± 0.2), and increased neonatal mortality (2.3-fold). Furthermore, preterm birth, dystocia, and fetal malformations were only observed in serotonin transporter null mice. This genetically ablated serotonin transporter mouse recapitulates several adverse pregnancy outcomes similar to those in women undergoing SSRI treatment during gestation. Additionally, neonatal loss in the present study reproduced a sudden infant death phenotype as in humans and mice with altered serotonergic signaling. In conclusion, findings from this study demonstrate a role for serotonin transporter in pregnancy maintenance and neonatal health. Additionally, it suggests that the adverse pregnancy outcomes in women taking SSRI during gestation might be due to altered serotonin transporter function caused by SSRI independent of underlying depression. This is a critical finding, given the number of women prescribed SSRI during pregnancy, and provides the framework for critical research in this area.

Effect of Low and High Doses of Two Selective Serotonin Reuptake Inhibitors on Pregnancy Outcomes and Neonatal Mortality

Selective serotonin reuptake inhibitors (SSRI) are the most common antidepressant used by pregnant women; however, they have been associated with adverse pregnancy outcomes and perinatal morbidity in pregnant women and animal models. We investigated the effects of two SSRI, fluoxetine and sertraline, on pregnancy and neonatal outcomes in mice. Wild-type mice were treated daily with low and high doses of fluoxetine (2 and 20 mg/kg) and sertraline (10 and 20 mg/kg) from the day of detection of a vaginal plug until the end of lactation (21 days postpartum). Pregnancy rate was decreased only in the high dose of fluoxetine group. Maternal weight gain was reduced in the groups receiving the high dose of each drug. Number of pups born was decreased in the high dose of fluoxetine and low and high doses of sertraline while the number of pups weaned was decreased in all SSRI-treated groups corresponding to increased neonatal mortality in all SSRI-treated groups. In conclusion, there was a dose-dependent effect of SSRI on pregnancy and neonatal outcomes in a non-depressed mouse model. However, the distinct placental transfer of each drug suggests that the effects of SSRI on pup mortality may be mediated by SSRI-induced placental insufficiency rather than a direct toxic effect on neonatal development and mortality.

Sudden Onset of Severe Pulmonary Hypertension in a Preterm Infant: A Case Report on the Role of Maternal Use of Serotonin Re-Uptake Inhibitors During Pregnancy and Concurrent Risk Factors

Persistent pulmonary hypertension of the newborn (PPHN) is a severe condition caused by failed circulatory adaptation at birth. Pulmonary hypertension is most common in full-term infants and rare in preterms, although it is increasingly diagnosed also in extremely preterm infants. Previous studies demonstrated the association between maternal use of selective serotonin re-uptake inhibitors during gestation and pulmonary hypertension. This brief report describes the complex physiopathological correlations that were identified in a case of severe pulmonary hypertension in a fetal growth restricted (FGR) preterm infant, with a history of maternal use of antidepressants during pregnancy. Perinatal factors, triggers and aggravating mechanisms caused a dramatic clinical course. Maternal history of escitalopram therapy throughout pregnancy was noted. Uteroplacental insufficiency, fetal hypoxia, FGR, preeclampsia, preterm delivery, antenatal steroids, and cesarean section were documented as concurrent risk factors. Myocardial immaturity and dysfunction, secondary to FGR and prematurity aggravated the hemodynamic compromise. The short time gap between pharmacological ductal closure and the onset of PPHN may suggest a cause-effect relationship, as observed in previous reports. Placental histopathologic findings are reported.

Placental Changes in the serotonin transporter (Slc6a4) knockout mouse suggest a role for serotonin in controlling nutrient acquisition

INTRODUCTION

The mouse placenta accumulates and possibly produces serotonin (5-hydroxytryptamine; 5-HT) in parietal trophoblast giant cells (pTGC) located at the interface between the placenta and maternal deciduum. However, the roles of 5-HT in placental function are unclear. This lack of information is unfortunate, given that selective serotonin-reuptake inhibitors are commonly used to combat depression in pregnant women. The high affinity 5-HT transporter SLC6A4 (also known as SERT) is the target of such drugs and likely controls much of 5-HT uptake into pTGC and other placental cells. We hypothesized that ablation of the Slc6a4 gene would result in morphological changes correlated with placental gene expression changes, especially for those involved in nutrient acquisition and metabolism, and thereby, provide insights into 5-HT placental function.

METHODS

Placentas were collected at embryonic age (E) 12.5 from Slc6a4 knockout (KO) and wild-type (WT) conceptuses. Histological analyses, RNAseq, qPCR, and integrative correlation analyses were performed.

RESULTS

Slc6a4 KO placentas had a considerable increased pTGC to spongiotrophoblast area ratio relative to WT placentas and significantly elevated expression of genes associated with intestinal functions, including nutrient sensing, uptake, and catabolism, and blood clotting. Integrative correlation analyses revealed upregulation of many of these genes was correlated with pTGC layer expansion. One other key gene was dopa decarboxylase (Ddc), which catalyzes conversion of L-5-hydroxytryptophan to 5-HT.

DISCUSSION

Our studies possibly suggest a new paradigm relating to how 5-HT operates in the placenta, namely as a factor regulating metabolic functions and blood coagulation. We further suggest that pTGC might be functional analogs of enterochromaffin 5-HT-positive cells of the intestinal mucosa, which regulate similar activities within the gut. Further work, including proteomics and metabolomic studies, are needed to buttress our hypothesis.

Transcriptomics and Other Omics Approaches to Investigate Effects of Xenobiotics on the Placenta

The conceptus is most vulnerable to developmental perturbation during its early stages when the events that create functional organ systems are being launched. As the placenta is in direct contact with maternal tissues, it readily encounters any xenobiotics in her bloodstream. Besides serving as a conduit for solutes and waste, the placenta possesses a tightly regulated endocrine system that is, of itself, vulnerable to pharmaceutical agents, endocrine disrupting chemicals (EDCs), and other environmental toxicants. To determine whether extrinsic factors affect placental function, transcriptomics and other omics approaches have become more widely used. In casting a wide net with such approaches, they have provided mechanistic insights into placental physiological and pathological responses and how placental responses may impact the fetus, especially the developing brain through the placenta-brain axis. This review will discuss how such omics technologies have been utilized to understand effects of EDCs, including the widely prevalent plasticizers bisphenol A (BPA), bisphenol S (BPS), and phthalates, other environmental toxicants, pharmaceutical agents, maternal smoking, and air pollution on placental gene expression, DNA methylation, and metabolomic profiles. It is also increasingly becoming clear that miRNA (miR) are important epigenetic regulators of placental function. Thus, the evidence to date that xenobiotics affect placental miR expression patterns will also be explored. Such omics approaches with mouse and human placenta will assuredly provide key biomarkers that may be used as barometers of exposure and can be targeted by early mitigation approaches to prevent later diseases, in particular neurobehavioral disorders, originating due to placental dysfunction.