September 11, 2001, initiated the longest period of armed conflict for the United States, during which, over the past decade, more than 2 million members of the U.S. Armed Forces have been deployed to combat.1 Military deployments have significant effects on the physical and mental health of American service members. However, the effects of military deployment on the family of American service members, frequently called the “overlooked causalities of war,” have been poorly investigated.2
Pregnant women whose spouses are deployed during pregnancy have reported higher levels of stress compared with women in a control group.3 Increased levels of stress and anxiety during pregnancy may increase the risk for preterm delivery, low birth weight, and preeclampsia.4–6 4–6 4–6
We were unable to identify any previous studies in the English literature examining the effects of spouse military deployment on perinatal outcomes by performing a PubMed search for the period from September 2011 to January 2015 using key words “military deployment” and “perinatal outcomes.” The effects of military deployment on women's health and pregnancy have been identified as an area needing further research by the American College of Obstetricians and Gynecologists.7 This topic is important not only to military obstetricians but also to civilian-practice obstetricians, because 52% of military dependents receive their obstetric care at civilian institutions.8
The primary objective of this study was to estimate whether spousal deployment during pregnancy increases the risk for adverse pregnancy outcomes. Further objectives were to evaluate whether group prenatal care may help improve adverse perinatal outcomes.
MATERIALS AND METHODS
We performed a prospective cohort study of primigravid women who delivered at Womack Army Medical Center located in Fort Bragg, North Carolina, between January 2013 and January 2014. To obtain a random sample of primigravid women receiving care at Womack Army Medical Center, a computer-generated randomization method was used to select patients for participation. Patients were approached at the time of their initial obstetric visit at the end of the first trimester. This study was approved by the Womack Army Medical Center institutional review board.
In 2012, there were a total of 2,843 births, of which 1,280 (45%) were to primigravid women. At the conclusion of 2012, a survey given at our institution showed 21.4% of women whose spouses were deployed during pregnancy delivered before 37 weeks of gestation in comparison with only 8.9% of women whose spouses were not deployed during their pregnancy.9 Based on this information, it was determined that a sample size of 138 women was needed in each group to obtain 80% power to test the difference in proportions of 9% and 21% for the rate of preterm delivery for the two groups. We anticipated that 40% of patients enrolled would be lost to follow-up, transfer care to another facility, or have incomplete charts that would preclude us from using their information; therefore, we planned on consenting 500 women for this study. Written informed consent was obtained from all women who agreed to participate in this study.
All women enrolled in the study were active-duty soldiers, spouses of active-duty soldiers, or dependents of active-duty soldiers. For the purpose of this study, spouse is defined as being married to the patient. Patients who reported their spouses were physically present with them for the entire pregnancy were designated as the nondeployed group; patients who reported their spouses were deployed to a combat zone during the entire pregnancy were designated the as deployed group.
Women excluded from the study were those whose spouses were not physically present with the patient during the entire pregnancy (eg, couple was separated or divorced or the spouse was participating in noncombat-related training) or spouses who were deployed to a combat zone during only portions of the pregnancy were excluded from this study. Lastly, women who consented to participate but did not have a complete prenatal and intrapartum records, transferred care to another facility, or did not follow-up at their postpartum visit were also excluded.
The electronic medical records of enrolled patients were reviewed by a study investigator who was blinded to whether the patient's spouse was deployed during the pregnancy. Demographic data obtained included age, prepregnancy body mass index, and participation in group prenatal care compared with traditional prenatal care. Comorbidities such as smoking, alcohol use, drug abuse, physical abuse during pregnancy, and pertinent medical history were also obtained. Patients were asked to complete a questionnaire at their postpartum visit to address the following information: whether the patient's spouse was deployed during their pregnancy and, if so, which trimester(s), the total household income, and the highest level of education the patient had completed.
Selected maternal characteristics, obstetric outcomes, and neonatal outcomes were compared between the two groups. Obstetric variables that were compared included maternal weight gain, mode of delivery, pregnancy complications, gestational age at the time of delivery (determined by a last menstrual period that was consistent with an ultrasonogram at less than 20 0/7 weeks of gestation, or, if the last menstrual period was unsure, an ultrasonogram at less than 20 0/7 weeks of gestation), and postpartum depression (defined as either a score of 14 or higher on the Edinburgh Postnatal Depression Scale or an International Classification of Diseases, 9th Revision diagnosis code for postpartum depression of 648.40 at the postpartum visit). The Edinburgh Postnatal Depression Scale was used as a proxy for the diagnosis of postpartum depression because it is routinely performed at our institution to screen for postpartum depression and a threshold of 14 was used because previous studies have demonstrated a score of 14 or higher to be a predictor for diagnosing depression.10 Women with an International Classification of Diseases, 9th Revision diagnosis code for postpartum depression or an Edinburgh Postnatal Depression Scale score of 14 or higher were subsequently referred to a behavioral health specialist for further evaluation and treatment.
Neonatal outcomes evaluated were neonatal birth weight, 5-minute Apgar score, neonatal intensive care unit admission, intubation of the neonate within 24 hours of birth, and neonatal death.
Pearson's χ2, Student's t test, and Fisher's exact test were used for univariate two-group comparison. Multivariable logistic regression analysis was used to obtain adjusted odds ratios (ORs) for postpartum depression. Adjustments were made for known risk factors and group differences. Fisher's exact test was used for all other obstetric and neonatal outcomes. Statistical computations were performed with SAS 9.4. Two-sided P values <.05 were judged statistically significant.
We arrived at our analytical sample size of 397 after a series of exclusions (Fig. 1). To achieve our goal of consenting 500 women, we randomly approached 1,643 women who presented for their initial prenatal visit at the conclusion of the first trimester. Once exclusion criteria were applied and the consenting process was completed, there were 500 patients. Once we reached this number, enrollment was closed. The final cohort of 397 resulted after 103 women were lost to follow-up or had incomplete records. This sample was then divided into two cohorts based on spouse deployment; the deployed group consisted of 183 women (46.1%) and the nondeployed group consisted of 214 women (53.9%).
Maternal demographic characteristics were not significantly different between groups (Table 1). The mean gestational age at delivery was 38.0±2.1 weeks for women in the deployed group, which was less than women in the nondeployed group who demonstrated a mean gestational age of 38.7±2.1 weeks (P=.01). There was no difference in the mean birth weight for the deployed group (3,218.8±609.9 g) compared with the nondeployed group (3,291.8±600.6 g, P=.23). Maternal weight gain in the deployed group was 29.8±11.5 lb compared with 29.8 ±13.5 lb for the nondeployed group (P=.99).
The rate of preterm delivery at less than 37 weeks of gestation was 20.8% for women in the deployed group and 7.5% for women in the nondeployed group (Table 2). Women in the deployed group were 3.24 times the odds to deliver less than 37 weeks of gestation as compared with women in the nondeployed group (OR 3.24 [1.74–6.04], P<.001). There were no statistically significant differences in the rates of preterm delivery at less than 34 weeks of gestation between the two groups (Table 2).
Maternal outcomes were compared between the deployed group and the nondeployed group (Table 3). Women in the deployed group were more likely to have a postpartum Edinburgh Postnatal Depression Scale of 14 or diagnosis of postpartum depression (16.4% compared with 6.1%). After adjusting for multiple confounders, the deployed group was at a significantly higher risk for postpartum depression by these criteria (adjusted OR 3.01 [1.53–6.03], P=.001). There were no other significant differences in maternal outcomes between the two groups. Regarding route of delivery, there were no differences in the frequency for cesarean delivery between the deployed and nondeployed groups (62 [33.9%] compared with 66 [30.8%], P=.24). Additionally, there were no statistically significant differences observed between the two groups with respect to neonatal outcomes (Table 4).
Lastly, we sought to determine whether participation in group prenatal care for members of the deployed group had any effect on the rates of preterm delivery and postpartum depression. We found no significant differences in the rates of preterm delivery and postpartum depression between prenatal care compared with traditional care in the deployed group (Table 5), although the study was not powered to evaluate these outcomes.
The results of this prospective cohort study show that deployment of a spouse to a combat zone during the entire pregnancy is associated with a 3.24-fold increased risk for preterm delivery and a 3.01-fold increased risk for postpartum depression compared with women whose spouses were not deployed to combat zones during any part of the pregnancy. Results of prior studies have shown that stress levels in spouses of deployed are significantly higher when compared with women in a control group.1,3 1,3 Increased stress during pregnancy has been associated with negative pregnancy outcomes such as preterm delivery and low birth weight, possibly secondary to release of stress hormones, which have a direct effect on uterine activity.11–17 11–17 11–17 11–17 11–17 11–17 11–17
Anxiety and stress are postulated to increase the risk for postpartum depression. Our study found women in the deployed group had a threefold increased risk for postpartum depression in comparison with the nondeployed group after controlling for multiple confounders. Prior studies evaluating rates of postpartum depression in women whose spouses were deployed either at the time of the postpartum visit or during pregnancy found increased rates of postpartum depression. Smith et al18 show a postpartum depression rate of 16.2% if spouses were deployed at the time of the postpartum visit compared with 8.1% among patients whose spouses were not deployed at the postpartum visit. Additionally, Robrecht et al19 demonstrate a 2.75-fold increased risk for postpartum depression among women whose spouses were deployed at some point during the pregnancy. Although these prior studies may not have accounted for the timing of deployment or adjusted for confounders, the results of our study and the prior strengthen our findings.
This study suggests deployment of a spouse during the entire pregnancy is associated with an increased risk for preterm delivery and postpartum depression. Given continuing conflict, American soldiers will continue to deploy to global hot spots; therefore, it is incumbent on us to find solutions to mitigate these risk factors because military commanders do not have the ability to prevent the deployment of soldiers with pregnant spouses as a result of operational constraints. One possible intervention that still allows for the deployment of the solider, which may possibly reduce adverse perinatal outcomes in this population, is group prenatal care. This care model allows eight to 12 women to go through their entire prenatal care together as a group with the same health care provider. There is evidence to suggest this model may be associated with lower rates of preterm delivery when compared with a traditional model.20–23 20–23 20–23 20–23 Our study was not powered to evaluate the differences between group prenatal care and this is an area that requires further investigation.
This study has several limitations. The study includes solely an Army population, which may limit generalizability of some of the findings. Additionally, the deployed group consisted of spouses deployed during the entire pregnancy. Therefore, this study cannot comment on whether there are any perinatal effects if a spouse were deployed for only a portion of the pregnancy.
The principal strength of our study is it is a large study that prospectively examines the overall effects of spouse deployment to a combat zone throughout pregnancy on obstetric and neonatal outcomes. In addition, this study accounted for multiple confounders for postpartum depression, which may have affected these outcomes.
In conclusion, we present evidence that deployment of a spouse during pregnancy may be associated with a higher risk for preterm delivery and postpartum depression. In the setting of continuing global conflict, it is likely that the United States will continue to engage in armed conflict. By identifying risk factors that may lead to preterm delivery and postpartum depression, we can implement strategies to reduce these adverse outcomes and financial costs associated with these complications. The results of this study are important to not just the military obstetrician, but all practicing obstetric providers in the United States because 50,000 live births occur at civilian institutions each year.8 We hope this study will serve as an impetus for future research that may assist in examining the effects of military deployment on subsequent pregnancy outcomes and, more importantly, interventions that, if implemented, may reduce these negative outcomes.
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© 2015 by The American College of Obstetricians and Gynecologists. Published by Wolters Kluwer Health, Inc. All rights reserved.
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