Letters to the Editor: Letter to the Editor
We thank Chaput and Vinturache for their interest in our study concerning the association between the use of epidural labor analgesia and the risk of postpartum depression.1,2
In our study, parturients with a history of antenatal depression were not excluded, nor were they screened for antenatal depression before study enrollment.2 This is an important limitation of the study design. Chaput and Vinturache stated that “depressed women are less likely to advocate for pain control” but did not provide a source for this statement. On the contrary, Andersson et al.3 found that epidural labor analgesia was used more commonly in women with antenatal depression and/or anxiety.
In a recent prospective cohort study of our group (unpublished data), 342 nulliparas with term singleton cephalic pregnancy who were preparing to deliver vaginally were enrolled, and 326 of them completed the final follow-up. The antenatal depression score was assessed in this study, and the percentage of parturients with antenatal depression (Edinburgh Postnatal Depression Scale score ≥10) was similar between those who received epidural analgesia and those who did not (16.6% [37 of 223] vs 13.6% [14 of 103], P = 0.488). Therefore, it seems that the antenatal depression mood may not decrease the acceptance of labor analgesia. Of course, further studies are needed to clarify this problem.
During the period of our study,2 morbid obesity (body mass index ≥35 kg/m2) was a relative contraindication of epidural analgesia in our hospital because we worried about the complications of the epidural procedure. To simplify the work of anesthesiologists, we adopted the exclusion criteria using body weight (body weight ≥100 kg). It was reported that women who are overweight or obese during pregnancy are more likely to develop postpartum depression.4 However, the same exclusion criteria that were applied for parturients of both groups decreased the risk of bias. Furthermore, we did not find any correlation between the presence of being overweight or obese and the occurrence of postpartum depression at 6 weeks (odds ratio, 0.94; 95% confidence interval, 0.44–2.01, P = 0.87).
We admit that the relative high loss to follow-up rate (17.4% [45 of 259]) is another important limitation of our study, especially when the rate was unequal between the 2 groups (21.9% [30 of 137] in parturients who received analgesia vs 12.3% [15 of 122] in those who did not).2 Patients with depression are less likely to follow medical recommendations,5 and some of the cited reasons leading to refusing follow-up in our study also indicated the possibility of depression development.6,7 It is possible that more depressive mothers were lost to follow-up in the epidural group than the mothers in the nonepidural group, thus directing our results toward the protective effects. However, it should be pointed out that at least 1 other observational trial, which was noted in our article, also supports a negative association between labor analgesia and postpartum depression.8
To address the concern of Chaput and Vinturache about the direction of the elimination process used during multivariate logistic regression, we performed analyses with either a forward or backward elimination method. The results were the same.
Considering the significant harmful effects of postpartum depression on both parents and children, the effects of epidural labor analgesia on the development of postpartum depression deserve further study.9 Chaput and Vinturache1 gave us some good suggestions for future study design, i.e., large sample size, depression-free participants, inclusion of obese parturients, low loss to follow-up rate, and appropriate methods of analysis.
Ting Ding, MD
Chun-Mei Deng, MD
Dong-Xin Wang, MD, PhD
Department of Anesthesiology
and Critical Care Medicine
Peking University First Hospital
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3. Andersson L, Sundström-Poromaa I, Wulff M, Aström M, Bixo M. Implications of antenatal depression and anxiety for obstetric outcome. Obstet Gynecol. 2004;104:467–76
4. Molyneaux E, Poston L, Ashurst-Williams S, Howard LM. Obesity and mental disorders during pregnancy and postpartum: a systematic review and meta-analysis. Obstet Gynecol. 2014;123:857–67
5. Ziegelstein RC, Fauerbach JA, Stevens SS, Romanelli J, Richter DP, Bush DE. Patients with depression are less likely to follow recommendations to reduce cardiac risk during recovery from a myocardial infarction. Arch Intern Med. 2000;160:1818–23
6. The Boston Women’s Health Book Collective: Our Bodies Ourselves.. 2005 New York, NY Touchstone Book:489–91
7. Alkozei A, McMahon E, Lahav A. Stress levels and depressive symptoms in NICU mothers in the early postpartum period. J Matern Fetal Neonatal Med. 2014;27:1738–43
8. Hiltunen P, Raudaskoski T, Ebeling H, Moilanen I. Does pain relief during delivery decrease the risk of postnatal depression? Acta Obstet Gynecol Scand. 2004;83:257–61
9. Lim G, Chelly JE. More research is required to demonstrate a relationship between intrapartum pain management and postpartum mood disorders. Anesth Analg. 2015;121:575