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Military pregnancies and adverse perinatal outcome
Iuefut&ulJsaulol
GYNECOLOGY &OB!8TETKlCS International Journal of Gynecology & Obstetrics 52 (1996) 19-24
Article
Military
pregnancies and adverse perinatal outcome *
E.F. Maganna, M.I. Winchesterb, D.P. Carterb, J.N. J.C. Morrison*a aDepartments
of Obstetrics
Martin
and Gynecology, University of Mississippi Medical Center, bNaval Hospilal, Pensacola, FL, USA ‘Louisiana Slate Universiry. New Orleans, LA, USA
Jra, T.E.
Nolanc,
Jackson,
(ISA
MS,
Received 22 May 1995; revision received 20 July 1995; accepted 27 July 1995
Abstract Objective: To identify significant risk factors for an adverse outcome in active-duty military women. Method: A prospective study of 105 pregnancies and their outcome. Results: The data revealed that: (1) single women more than married personnel had cesarean births when compared with forceps and vacuum (P < 0.03) or spontaneous vaginal delivery (P < 0.04); and (2) active-duty women who gained < 25 pounds during pregnancy developed pretenn labor more often (P < 0.05). Conclusion: Risk factors for these adverse outcomes remain unknown. Keywords: Risk factors; Military
pregnancy
1. Introduction Active-duty women will continue to be an integral part of the all-volunteer military force in spite of the current downsizing of the armed services. The percentage of women entering the military remains at an all-time high with 13% of active-duty service personnel being female. These women are in the reproductive age group and do *The opinions expressed herein are those of the authors and not necessarily those of the United States Navy or the Department of Defense. *Corresponding author, Fax: +l 601 9845301.
not delay childbearing because of service obligation [l-3]. The diagnosis of pregnancy no longer mandates release of women from active duty. Pregnancies in active-duty personnel are at high risk for both maternal and neonatal complications [l-3]. Cesarean birth, operative vaginal delivery, intrauterine growth retardation (IUGR) and pregnancy-induced hypertension are significantly increased in active-duty women [3]. Factors which have been suggested to affect non-military pregnancy outcome include: maternal height, maternal weight gain during pregnancy, education, socioeconomic status, race, age, cigarette smoking and the consumption of alcohol during pregnancy
0020-729296LS15.00 0 1996 International Federation of Gynecology and Obstetrics SSDI 0020-7292(95)02530-P
20
E.F. Magann
et al. /International
Journal
[4-81. Are the components which contribute to make military pregnancies high risk the same or different than the recognized factors which are associated with adverse pregnancy outcomes in non-service-connected gestations? The purpose of this study was to evaluate our original findings of an adverse pregnancy outcome in an active-duty population [3] and to identify the risk factors which place an active-duty servicewoman’s pregnancy at high risk. 2. Materials
and methods
This prospective study was conducted from September 1991 through April 1992 with 105 consecutive deliveries of active-duty women at the Naval Hospital, Pensacola, Florida. An activeduty pregnancy is defined as a gestation in a woman who is on active duty in the Armed Forces of the United States and remains on active duty throughout her entire pregnancy. The pregnancies were evaluated for the incidence of cesarean birth, spontaneous or operative vaginal delivery, preeclampsia-eclampsia, preterm labor, maternal transport for fetal indications, term infant weight ~2500 g, intrauterine fetal demise, abruptio placenta, postpartum hemorrhage and placenta previa. All 105 women were categorized by age, parity, race, rank (three groups: enlisted ranks E-l to E-4, enlisted ranks E-5 to E-8, and officers), marital status, highest educational level obtained (high school graduate, attended college, and college graduate), smoking during pregnancy (> 20 cigarette/day), any alcohol use during pregnancy, maternal height, and weight gain during pregnancy (~25 pounds, 25-35 pounds and > 35 pounds). The rank breakdown was designated for two reasons. All families of E-4 and below with either a single parent or only the service person employed would have gross annual incomes below $16 5 10 and would qualify for food stamps according to the U.S. Department of Agriculture regulations. Supervisory-type roles in the military begin at the rank of E-5. Additionally, at this rank, enlisted women have the opportunity to structure a personal work environment in which to function. One hundred of the 105 women were employed in ad-
of Gynecology
& Obstetrics
52 (1996)
19-24
ministrative occupations. All patients registered for prenatal care in the first trimester of pregnancy. Information was obtained by individual patient interviews, prenatal charts, hospital records and the delivery room log book. During the study all patients received their obstetric care from six obstetricians and two obstetrics-gynecology nurse practitioners. Obstetric care was continuously available 24 h a day by an in-house physician. Obstetric pain management during labor was by intravenous sedation with only a limited epidural service available mainly for cesarean delivery. Statistical analysis was done using the chisquared test, Fisher’s exact test and multivariate analysis. A P-value of co.05 was considered significant. 3. Results Maternal age, marital status, alcohol consumption, cigarette smoking during pregnancy, race, parity, maternal height, weight gain during pregnancy and rank were determined in all 105 activeduty pregnant women (Table 1). Forty-seven had adverse pregnancy outcomes as defined by cesarean birth, IUGR (fetal weight < 2500 g at term), 5-min Apgar score < 7, preterm labor, intrauterine fetal demise, abruptio placenta, placenta previa or postpartum hemorrhage. When this group of 47 patients was compared with the 58 pregnancies without complications, there were no Table 1 Demographic characteristics of the study subjects No. of pregnant active-duty women evaluated: 105 Mean maternal age: 25.22 f 4.65 years (range 19-40) Marital status: 61 married, 44 single Alcohol consumption while pregnant: 8 yes, 97 no Smoking while pregnant: 21 yes, 84 no Race: 75 Caucasian, 27 Black, 3 Hispanic Education: 77 completed high school, 24 some college, 4 college graduates Parity (O/1/2/3): 61/33/8/3 Maternal height ( < 60“/60-65“/ > 65”): 5/60/40 Weight gain during pregnancy (<25 lb/25-35 lb/>35 18144143 Rank (E-l to E-4/E-4 to E-LVofftcer): 70/27/8
lb):
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et al. /International
Journal
significant differences in age, gravidity, race, rank, marital status, education level obtained, smoking > 20 cigarettes/day, any alcohol consumption during pregnancy, maternal height, or weight gain during pregnancy between the two groups (P = NS).
Each category of pregnancy complication was then assessed individually. An evaluation of the route of delivery showed that 23 patients delivered abdominally, 13 by operative vaginal delivery and 69 by spontaneous vaginal delivery. Significantly more single (14/44) than married personnel (8161) underwent abdominal delivery rather than operative vaginal delivery or spontaneous vaginal delivery (O.R. 0.3, 95% C.I. 0.11-0.95, P C 0.04). The indications for cesarean delivery were not significantly different between single and married servicewomen. Maternal age and gravidity were not significantly different between the married and single women within any of the three groups or among the three groups when mode of delivery was assessed. The incidences of smoking, alcohol consumption during pregnancy, race, educational level obtained, gravidity, parity, maternal height, maternal weight gain during pregnancy and military rank were not significantly different when mode of delivery was analyzed. Twelve patients experienced preterm labor. This was defined as repetitive, regular uterine contractions productive of cervical dilatation, effacement and/or descent prior to the 37th week of pregnancy. Preterm labor in women whose pregnancy weight gain was < 25 pounds (5/l 8) demonstrated a significant association relative to other preterm labor patients who gained >25 pounds (7187) (O.R. 4.39, 95% C.I. 1-18.9, P < 0.05). Marital status, race, rank, educational attainment, parity, cigarette smoking during pregnancy, alcohol consumption during pregnancy and maternal height were not significantly different between the patients with preterm labor and the other active-duty women. Three pregnancies had an infant born at term but with a birth weight <2500 g. Eight subjects delivered a newborn with 5-min Apgar scores < 7. Sixteen gestations were complicated by preeclampsia and three patients were transferred antenatally to a tertiary care facility. Abruptio placenta oc-
of Gynecology
& Obstetrics
52 (1996)
19-24
21
curred in one pregnancy and postpartum hemorrhage occurred in two pregnancies. There was no intrauterine fetal demise or placenta previa encountered in this series. Comparisons of these complications of pregnancy with the other women who had normal gestations showed no significant differences in marital status, race, rank, educational attainment, parity, cigarette smoking, alcohol consumption while pregnant, maternal height, and maternal weight gain during pregnancy. 4. Discussion Active-duty military pregnancies have been shown to be frequently associated with poor pregnancy outcome [l]. The incidence of cesarean delivery, transfer for preterm complications, and complications of pregnancy such as pregnancyinduced hypertension and IUGR are more common in active-duty women [3]. The reasons for these findings have not been elucidated. Upon application for entrance. into the military, all of the inductees have a thorough evaluation of their past medical and family history. Each one also has a complete physical examination, complete blood count, urinalysis, SMA-18, VDRL, HIV, chest Xray and electrocardiogram. An abnormality of any of these laboratory tests, the physical examination, or the medical history can be used to disqualify an applicant for induction into the armed forces. In order to carry out the mission of the military, the candidate must be in good health, free of disease and have no chronic medical problems. Therefore these women have mandatory annual physical examinations, Pap smears and HIV tests. The active-duty woman’s health care is not only global and compulsory, but also without expense to her. The servicewoman should then, by superficial analysis, enter the service in a healthy state. The current evidence presented reveals that these healthy women then are exposed to an unknown risk factor or factors when they become pregnant and the outcome of their pregnancy is adversely affected. Our previous study evaluated pregnancy outcome in 331 active-duty women and compared them with 1218 dependent wives cared for by the same physicians in the same hospital and over the
22
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et al. /International
Journal
Table 2 Comparison of the Camp Lejeune and Pensacola military studies Pregnancy outcome study
Cesarean section (%) Operative vaginal delivery (%) S-min Apgar score < 7 (%) Preterm labor (%) Maternal transfer (%) Preeclampsia (%) IUGR (birth weight ~2500 g, %)
Camp Lejeune
Pensacola
23.0 10.3 1.5 2.1 3.3 6.7 2.4
22.0 12.4 7.5 II.4 2.9 15.2 2.9
same time span [3]. Since they are prohibited by law to engage in direct combat, these active-duty marines provided support services to the largest marine corps training facility on the East Coast. In contrast, the present investigation evaluated servicewomen who provide support services for the training of jet pilots. Although our present study is focused on a different branch of the service, its members provide administrative support (i.e. clerical, communications, radar, etc) to a naval air station (no field/strenuous work). All medical care in both locations was provided in naval treatment facilities by Navy physicians and midwives. The pregnancy outcomes and complications found in that study are comparable to the findings in our present study (Table 2). Both of these investigations support the conclusion that the risks associated with a military pregnancy persist despite the branch of service. What remains unclear are the reasonswhy these pregnancies are high risk. In another investigation, the factor of maternal height has been suggestedas a useful tool to predict which patient would require operative delivery (forceps, vacuum or cesareanbirth) becauseof a smaller pelvis in relation to fetal size in shorter women [7]. The current data did not show any difference in the operative delivery rate relative to short stature in military women. Two possibleexplanations include the minimum military height requirement and the minimum age of 19 years, which eliminate the immature pelvis as a causeof increased operative deliveries.
of Gynecology
& Obstetrics
52 (1996)
19-24
Cigarette smoking has been associatednot only with low birth weight and increasedfetal death but also with placenta previa [5,6]. No association between smoking and any complication of pregnancy was demonstrated in our study, however. The rigorous anti-smoking campaign by the military and the fact that only two of the 22 patients who acknowledged smoking during pregnancy smoked more than 20 cigarettes per day may have contributed to the apparent lack of any significant impact of smoking on adverse pregnancy outcome in this population. Alcohol consumption and the fetal alcohol syndrome is well recognized. A low birth weight infant is the most reliably observed consequenceof alcohol consumption during pregnancy [8]. Only sevenwomen acknowledged alcohol consumption during pregnancy. There was no significant difference for any of the adverse pregnancy outcome categories evaluated. Education by health care providers specifically and the Navy in general may be instrumental in making alcohol consumption a non-factor in the studied population. Marital status and a low socioeconomic status have been associated with preterm birth [4]. Twelve of the women experienced preterm labor, but neither marital status (44 of the women were single) nor socioeconomicstatus (63 of the women were of rank E-4 and below) were significantly associatedwith preterm labor or early delivery in this investigation. Correlation of formal maternal education and pregnancy outcome have been related to low birth weight, increased perinatal death rate and neonatal neurologic abnormalities [9]. Education level by itself does not alter the hazards of pregnancy but probably reflects the socioeconomic status of the patient. Seventy-five percent of the women had achieved a high school education. However there was no apparent difference between the maternalperinatal outcome of these patients and the 25% who had somecollege education. Our population, however, would be considered educated because all were high school graduates in contrast to other populations where many women would not be high school graduates. The number of single women compared with married women who underwent a cesarean delivery was significantly greater than those delivering
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by forceps, vacuum or spontaneous delivery. Even though cesarean birth occurred more frequently in single women, the indications for cesarean delivery were not significantly different between the two groups. Parity, race and age were also equivalent between the groups. The reason for the increased number of single women undergoing a cesarean section remains elusive. The number of pregnancies complicated by preterm labor (12%) was much higher than that seen in a recent military study [3]. The only correlation was found in those women whose maternal weight gain during pregnancy was <25 pounds (P < 0.05). Low maternal weight gain in pregnancy, particularly when extreme (defined as < 18 pounds), has been associated with preterm labor [3]. The other known reproducible risk factors [ 101 for preterm labor including socioeconomic status, race, age, prepregnancy weight and smoking were not significantly different between patient groups. The pretenn delivery rate among black and white enlisted women is not significant ,except in deliveries before 33 weeks and for medically indicated preterm deliveries [ 111. The common elements for these women are their active-duty status and full-time work. Physical activity has been suggested as a risk factor for preterm labor in U.S. Army primigravidas [12]. Moderate to strenuous physical activity in wellconditioned athletes, however, did not appear to cause adverse outcomes in pregnancy in other studies [ 13,141. Alternatives to regular exercise are available to active-duty women but the impact of exercise on pregnant servicewomen has not been assessed. Adverse effects of low birth weight and preterm delivery have been found to be significantly more common in manual workers requested to do strenuous activity in Scotland [ 151. Previous studies have found no alteration in birth weight and the incidence of preterm labor in women who exercise during pregnancy or engage in heavy work [ 131. Working long hours in a stressful environment was also not associated with an adverse pregnancy outcome in a national survey of resident physicians [16]. Psychosocial stresses in the workplace have been associated with preterm labor and low birth weight, particularly in those women not motivated to remain in the workplace [ 171. The relationship between work and preg-
of Gynecology
& Obstetrics
52 (1996)
19-24
23
nancy outcome has not been investigated in an active-duty population. Socioeconomically, active-duty women were in the low group because of education and rank and, because of these factors, had little control over their workplace. Seventy of 105 patients were of the rank E-4 or below and of those enlisted women over the rank of E-4 (27), only two would have qualified for managerial positions. The military occupations of the majority of these women are characterized by high levels of psychologic demand with little control over the pace and style of response to those demands. In addition these jobs involve moderate physical exercise and are at an income which places the majority of these women at or below the poverty level - common factors which are present in the majority of these military pregnancies. Are these the factors which render the military pregnancy at high risk? Identification of military pregnancies as high risk has important implications not only for the military physicians providing health care but also for obstetricians in general. As the number of health care providers in the military is reduced, more servicewomen will receive their obstetric care from obstetricians in the private sector. These practitioners should be aware of the high-risk status of servicewomen in order to provide adequate care. Analysis of the data from this study did not allow us to identify known risk factors for an adverse pregnancy outcome as those responsible for the poor pregnancy outcome in active-duty military pregnancies. Socioeconomic factors and a stressful work environment over which the women have little control is consistently identified in these pregnancies and would appear to be a logical area for future investigation. Acknowledgment
This study was supported in part Vicksburg Hospital Medical Foundation.
by the
References [I]
[2]
Fox ME, Harris RE, Brekken AL. The active-duty military pregnancy: a new high risk category. Am J Obstet Gynecol 1977; 129: 707-709. Hauth JC, Gilstrap LC, Brekken AL, Hauth JM. The effect of 17a-hydroxyprogesterone caproate on preg-
24
[3] [4] (51 [6] [7] IS] [9] [lo] [ll]
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Journal
nancy outcome in an active-duty military population. Am J Obstet Gynecol 1983; 146: 187-190. Magann EF, Nolan TE. Pregnancy outcome in an activeduty population. Obstet Gynecol 1991; 78: 391-393. Creasy RK, Gummer BA, Liggins GC. System for predicting spontaneous preterm birth. Obstet Gynecol 1980; 55: 692-695. Kleinman JC, Pierre MB Jr, Madans JH et al. The effects of maternal smoking on fetal and infant mortality. Am J Epidemiol 1988; 127: 274-282. Meyer MB, Jonas BS, Tonascia JA. Perinatal events associated with maternal smoking during pregnancy. Am J Epidemiol 1976; 103: 464-476. Roosmalen J, Brand R. Maternal height and the outcome of labor in rural Tanzania. Br J Gynaecol Obstet 1992; 37: 169-177. Sokol RJ, Miller SI, Reed J. Alcohol abuse during pregnancy. An epidemiologic study. Alcohol Clin Exp Res 1980; 4: 135-145. Aumann GM, Bairn MM. Screening for the high-risk pregnancy. In: Knuppel RA, Drukker JE, editors. High risk pregnancy. Philadelphia, PA: Saunders, 1986: 3-23. Main DM. The epidemiology of preterm birth. Clin Obstet Gynecol 1988; 31: 521-532. Adams MM, Read JA, Rawlings JS, Harless FB, Sanno
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& Obstetrics
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AP, Rhodes PH. Preterm delivery among black and white enlisted women in the United States Anny. Obstet Gynecol 1993; 81: 65-71. [12] Ramirez G, Grimes RM, Annegers JF, Davis BR, Slater CH. Occupational physical activity and other risk factors for preterm birth among US Army primigavidas. Am J Public Health 1990, 80: 728-729. 1131 Klebanoff MA, Shiono PH, Carey JC. The effect of physical activity during pregnancy on preterm delivery and birth weight. Am J Obstet Gynecol 1990, 163: 1450- 1456. [I41 Rose NC, Haddow JE, Palomaki BS, Knight GJ. Selfrated physical activity level during the second trimester and pregnancy outcome. Obstet Gynecol 1991; 78: 1078-1080. [I51 Sanjose S, Koman E, Beral V. Low birthweight and preterm delivery, Scotland 1981-1984. Effect of patients’ occupation. Lancet 1991; 338: 428-431. [16] Klebanoff MA, Shiono PH, Rhoads GG. Outcomes of pregnancy in a national sample of resident physicians. N Engl J Med 1990, 323: 1040-1045. 1171 Homer CJ, James SA, Siegel E. Work-related psychosocial stressand risks of preterm, low birthweight delivery. Am J Public Health 1990; 80: 173-717.
GYNECOLOGY &OB!8TETKlCS International Journal of Gynecology & Obstetrics 52 (1996) 19-24
Article
Military
pregnancies and adverse perinatal outcome *
E.F. Maganna, M.I. Winchesterb, D.P. Carterb, J.N. J.C. Morrison*a aDepartments
of Obstetrics
Martin
and Gynecology, University of Mississippi Medical Center, bNaval Hospilal, Pensacola, FL, USA ‘Louisiana Slate Universiry. New Orleans, LA, USA
Jra, T.E.
Nolanc,
Jackson,
(ISA
MS,
Received 22 May 1995; revision received 20 July 1995; accepted 27 July 1995
Abstract Objective: To identify significant risk factors for an adverse outcome in active-duty military women. Method: A prospective study of 105 pregnancies and their outcome. Results: The data revealed that: (1) single women more than married personnel had cesarean births when compared with forceps and vacuum (P < 0.03) or spontaneous vaginal delivery (P < 0.04); and (2) active-duty women who gained < 25 pounds during pregnancy developed pretenn labor more often (P < 0.05). Conclusion: Risk factors for these adverse outcomes remain unknown. Keywords: Risk factors; Military
pregnancy
1. Introduction Active-duty women will continue to be an integral part of the all-volunteer military force in spite of the current downsizing of the armed services. The percentage of women entering the military remains at an all-time high with 13% of active-duty service personnel being female. These women are in the reproductive age group and do *The opinions expressed herein are those of the authors and not necessarily those of the United States Navy or the Department of Defense. *Corresponding author, Fax: +l 601 9845301.
not delay childbearing because of service obligation [l-3]. The diagnosis of pregnancy no longer mandates release of women from active duty. Pregnancies in active-duty personnel are at high risk for both maternal and neonatal complications [l-3]. Cesarean birth, operative vaginal delivery, intrauterine growth retardation (IUGR) and pregnancy-induced hypertension are significantly increased in active-duty women [3]. Factors which have been suggested to affect non-military pregnancy outcome include: maternal height, maternal weight gain during pregnancy, education, socioeconomic status, race, age, cigarette smoking and the consumption of alcohol during pregnancy
0020-729296LS15.00 0 1996 International Federation of Gynecology and Obstetrics SSDI 0020-7292(95)02530-P
20
E.F. Magann
et al. /International
Journal
[4-81. Are the components which contribute to make military pregnancies high risk the same or different than the recognized factors which are associated with adverse pregnancy outcomes in non-service-connected gestations? The purpose of this study was to evaluate our original findings of an adverse pregnancy outcome in an active-duty population [3] and to identify the risk factors which place an active-duty servicewoman’s pregnancy at high risk. 2. Materials
and methods
This prospective study was conducted from September 1991 through April 1992 with 105 consecutive deliveries of active-duty women at the Naval Hospital, Pensacola, Florida. An activeduty pregnancy is defined as a gestation in a woman who is on active duty in the Armed Forces of the United States and remains on active duty throughout her entire pregnancy. The pregnancies were evaluated for the incidence of cesarean birth, spontaneous or operative vaginal delivery, preeclampsia-eclampsia, preterm labor, maternal transport for fetal indications, term infant weight ~2500 g, intrauterine fetal demise, abruptio placenta, postpartum hemorrhage and placenta previa. All 105 women were categorized by age, parity, race, rank (three groups: enlisted ranks E-l to E-4, enlisted ranks E-5 to E-8, and officers), marital status, highest educational level obtained (high school graduate, attended college, and college graduate), smoking during pregnancy (> 20 cigarette/day), any alcohol use during pregnancy, maternal height, and weight gain during pregnancy (~25 pounds, 25-35 pounds and > 35 pounds). The rank breakdown was designated for two reasons. All families of E-4 and below with either a single parent or only the service person employed would have gross annual incomes below $16 5 10 and would qualify for food stamps according to the U.S. Department of Agriculture regulations. Supervisory-type roles in the military begin at the rank of E-5. Additionally, at this rank, enlisted women have the opportunity to structure a personal work environment in which to function. One hundred of the 105 women were employed in ad-
of Gynecology
& Obstetrics
52 (1996)
19-24
ministrative occupations. All patients registered for prenatal care in the first trimester of pregnancy. Information was obtained by individual patient interviews, prenatal charts, hospital records and the delivery room log book. During the study all patients received their obstetric care from six obstetricians and two obstetrics-gynecology nurse practitioners. Obstetric care was continuously available 24 h a day by an in-house physician. Obstetric pain management during labor was by intravenous sedation with only a limited epidural service available mainly for cesarean delivery. Statistical analysis was done using the chisquared test, Fisher’s exact test and multivariate analysis. A P-value of co.05 was considered significant. 3. Results Maternal age, marital status, alcohol consumption, cigarette smoking during pregnancy, race, parity, maternal height, weight gain during pregnancy and rank were determined in all 105 activeduty pregnant women (Table 1). Forty-seven had adverse pregnancy outcomes as defined by cesarean birth, IUGR (fetal weight < 2500 g at term), 5-min Apgar score < 7, preterm labor, intrauterine fetal demise, abruptio placenta, placenta previa or postpartum hemorrhage. When this group of 47 patients was compared with the 58 pregnancies without complications, there were no Table 1 Demographic characteristics of the study subjects No. of pregnant active-duty women evaluated: 105 Mean maternal age: 25.22 f 4.65 years (range 19-40) Marital status: 61 married, 44 single Alcohol consumption while pregnant: 8 yes, 97 no Smoking while pregnant: 21 yes, 84 no Race: 75 Caucasian, 27 Black, 3 Hispanic Education: 77 completed high school, 24 some college, 4 college graduates Parity (O/1/2/3): 61/33/8/3 Maternal height ( < 60“/60-65“/ > 65”): 5/60/40 Weight gain during pregnancy (<25 lb/25-35 lb/>35 18144143 Rank (E-l to E-4/E-4 to E-LVofftcer): 70/27/8
lb):
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et al. /International
Journal
significant differences in age, gravidity, race, rank, marital status, education level obtained, smoking > 20 cigarettes/day, any alcohol consumption during pregnancy, maternal height, or weight gain during pregnancy between the two groups (P = NS).
Each category of pregnancy complication was then assessed individually. An evaluation of the route of delivery showed that 23 patients delivered abdominally, 13 by operative vaginal delivery and 69 by spontaneous vaginal delivery. Significantly more single (14/44) than married personnel (8161) underwent abdominal delivery rather than operative vaginal delivery or spontaneous vaginal delivery (O.R. 0.3, 95% C.I. 0.11-0.95, P C 0.04). The indications for cesarean delivery were not significantly different between single and married servicewomen. Maternal age and gravidity were not significantly different between the married and single women within any of the three groups or among the three groups when mode of delivery was assessed. The incidences of smoking, alcohol consumption during pregnancy, race, educational level obtained, gravidity, parity, maternal height, maternal weight gain during pregnancy and military rank were not significantly different when mode of delivery was analyzed. Twelve patients experienced preterm labor. This was defined as repetitive, regular uterine contractions productive of cervical dilatation, effacement and/or descent prior to the 37th week of pregnancy. Preterm labor in women whose pregnancy weight gain was < 25 pounds (5/l 8) demonstrated a significant association relative to other preterm labor patients who gained >25 pounds (7187) (O.R. 4.39, 95% C.I. 1-18.9, P < 0.05). Marital status, race, rank, educational attainment, parity, cigarette smoking during pregnancy, alcohol consumption during pregnancy and maternal height were not significantly different between the patients with preterm labor and the other active-duty women. Three pregnancies had an infant born at term but with a birth weight <2500 g. Eight subjects delivered a newborn with 5-min Apgar scores < 7. Sixteen gestations were complicated by preeclampsia and three patients were transferred antenatally to a tertiary care facility. Abruptio placenta oc-
of Gynecology
& Obstetrics
52 (1996)
19-24
21
curred in one pregnancy and postpartum hemorrhage occurred in two pregnancies. There was no intrauterine fetal demise or placenta previa encountered in this series. Comparisons of these complications of pregnancy with the other women who had normal gestations showed no significant differences in marital status, race, rank, educational attainment, parity, cigarette smoking, alcohol consumption while pregnant, maternal height, and maternal weight gain during pregnancy. 4. Discussion Active-duty military pregnancies have been shown to be frequently associated with poor pregnancy outcome [l]. The incidence of cesarean delivery, transfer for preterm complications, and complications of pregnancy such as pregnancyinduced hypertension and IUGR are more common in active-duty women [3]. The reasons for these findings have not been elucidated. Upon application for entrance. into the military, all of the inductees have a thorough evaluation of their past medical and family history. Each one also has a complete physical examination, complete blood count, urinalysis, SMA-18, VDRL, HIV, chest Xray and electrocardiogram. An abnormality of any of these laboratory tests, the physical examination, or the medical history can be used to disqualify an applicant for induction into the armed forces. In order to carry out the mission of the military, the candidate must be in good health, free of disease and have no chronic medical problems. Therefore these women have mandatory annual physical examinations, Pap smears and HIV tests. The active-duty woman’s health care is not only global and compulsory, but also without expense to her. The servicewoman should then, by superficial analysis, enter the service in a healthy state. The current evidence presented reveals that these healthy women then are exposed to an unknown risk factor or factors when they become pregnant and the outcome of their pregnancy is adversely affected. Our previous study evaluated pregnancy outcome in 331 active-duty women and compared them with 1218 dependent wives cared for by the same physicians in the same hospital and over the
22
E.F. Magann
et al. /International
Journal
Table 2 Comparison of the Camp Lejeune and Pensacola military studies Pregnancy outcome study
Cesarean section (%) Operative vaginal delivery (%) S-min Apgar score < 7 (%) Preterm labor (%) Maternal transfer (%) Preeclampsia (%) IUGR (birth weight ~2500 g, %)
Camp Lejeune
Pensacola
23.0 10.3 1.5 2.1 3.3 6.7 2.4
22.0 12.4 7.5 II.4 2.9 15.2 2.9
same time span [3]. Since they are prohibited by law to engage in direct combat, these active-duty marines provided support services to the largest marine corps training facility on the East Coast. In contrast, the present investigation evaluated servicewomen who provide support services for the training of jet pilots. Although our present study is focused on a different branch of the service, its members provide administrative support (i.e. clerical, communications, radar, etc) to a naval air station (no field/strenuous work). All medical care in both locations was provided in naval treatment facilities by Navy physicians and midwives. The pregnancy outcomes and complications found in that study are comparable to the findings in our present study (Table 2). Both of these investigations support the conclusion that the risks associated with a military pregnancy persist despite the branch of service. What remains unclear are the reasonswhy these pregnancies are high risk. In another investigation, the factor of maternal height has been suggestedas a useful tool to predict which patient would require operative delivery (forceps, vacuum or cesareanbirth) becauseof a smaller pelvis in relation to fetal size in shorter women [7]. The current data did not show any difference in the operative delivery rate relative to short stature in military women. Two possibleexplanations include the minimum military height requirement and the minimum age of 19 years, which eliminate the immature pelvis as a causeof increased operative deliveries.
of Gynecology
& Obstetrics
52 (1996)
19-24
Cigarette smoking has been associatednot only with low birth weight and increasedfetal death but also with placenta previa [5,6]. No association between smoking and any complication of pregnancy was demonstrated in our study, however. The rigorous anti-smoking campaign by the military and the fact that only two of the 22 patients who acknowledged smoking during pregnancy smoked more than 20 cigarettes per day may have contributed to the apparent lack of any significant impact of smoking on adverse pregnancy outcome in this population. Alcohol consumption and the fetal alcohol syndrome is well recognized. A low birth weight infant is the most reliably observed consequenceof alcohol consumption during pregnancy [8]. Only sevenwomen acknowledged alcohol consumption during pregnancy. There was no significant difference for any of the adverse pregnancy outcome categories evaluated. Education by health care providers specifically and the Navy in general may be instrumental in making alcohol consumption a non-factor in the studied population. Marital status and a low socioeconomic status have been associated with preterm birth [4]. Twelve of the women experienced preterm labor, but neither marital status (44 of the women were single) nor socioeconomicstatus (63 of the women were of rank E-4 and below) were significantly associatedwith preterm labor or early delivery in this investigation. Correlation of formal maternal education and pregnancy outcome have been related to low birth weight, increased perinatal death rate and neonatal neurologic abnormalities [9]. Education level by itself does not alter the hazards of pregnancy but probably reflects the socioeconomic status of the patient. Seventy-five percent of the women had achieved a high school education. However there was no apparent difference between the maternalperinatal outcome of these patients and the 25% who had somecollege education. Our population, however, would be considered educated because all were high school graduates in contrast to other populations where many women would not be high school graduates. The number of single women compared with married women who underwent a cesarean delivery was significantly greater than those delivering
E.F. Magann
et al. /International
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by forceps, vacuum or spontaneous delivery. Even though cesarean birth occurred more frequently in single women, the indications for cesarean delivery were not significantly different between the two groups. Parity, race and age were also equivalent between the groups. The reason for the increased number of single women undergoing a cesarean section remains elusive. The number of pregnancies complicated by preterm labor (12%) was much higher than that seen in a recent military study [3]. The only correlation was found in those women whose maternal weight gain during pregnancy was <25 pounds (P < 0.05). Low maternal weight gain in pregnancy, particularly when extreme (defined as < 18 pounds), has been associated with preterm labor [3]. The other known reproducible risk factors [ 101 for preterm labor including socioeconomic status, race, age, prepregnancy weight and smoking were not significantly different between patient groups. The pretenn delivery rate among black and white enlisted women is not significant ,except in deliveries before 33 weeks and for medically indicated preterm deliveries [ 111. The common elements for these women are their active-duty status and full-time work. Physical activity has been suggested as a risk factor for preterm labor in U.S. Army primigravidas [12]. Moderate to strenuous physical activity in wellconditioned athletes, however, did not appear to cause adverse outcomes in pregnancy in other studies [ 13,141. Alternatives to regular exercise are available to active-duty women but the impact of exercise on pregnant servicewomen has not been assessed. Adverse effects of low birth weight and preterm delivery have been found to be significantly more common in manual workers requested to do strenuous activity in Scotland [ 151. Previous studies have found no alteration in birth weight and the incidence of preterm labor in women who exercise during pregnancy or engage in heavy work [ 131. Working long hours in a stressful environment was also not associated with an adverse pregnancy outcome in a national survey of resident physicians [16]. Psychosocial stresses in the workplace have been associated with preterm labor and low birth weight, particularly in those women not motivated to remain in the workplace [ 171. The relationship between work and preg-
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23
nancy outcome has not been investigated in an active-duty population. Socioeconomically, active-duty women were in the low group because of education and rank and, because of these factors, had little control over their workplace. Seventy of 105 patients were of the rank E-4 or below and of those enlisted women over the rank of E-4 (27), only two would have qualified for managerial positions. The military occupations of the majority of these women are characterized by high levels of psychologic demand with little control over the pace and style of response to those demands. In addition these jobs involve moderate physical exercise and are at an income which places the majority of these women at or below the poverty level - common factors which are present in the majority of these military pregnancies. Are these the factors which render the military pregnancy at high risk? Identification of military pregnancies as high risk has important implications not only for the military physicians providing health care but also for obstetricians in general. As the number of health care providers in the military is reduced, more servicewomen will receive their obstetric care from obstetricians in the private sector. These practitioners should be aware of the high-risk status of servicewomen in order to provide adequate care. Analysis of the data from this study did not allow us to identify known risk factors for an adverse pregnancy outcome as those responsible for the poor pregnancy outcome in active-duty military pregnancies. Socioeconomic factors and a stressful work environment over which the women have little control is consistently identified in these pregnancies and would appear to be a logical area for future investigation. Acknowledgment
This study was supported in part Vicksburg Hospital Medical Foundation.
by the
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