- Email: [email protected]
Teenage Maternity: A Study from Seven City Hospitals in Taipei
■ ORIGINAL ARTICLE ■
C.L. Lin, et al
TEENAGE MATERNITY: A STUDY FROM SEVEN CITY HOSPITALS IN TAIPEI 1
1,2
Chen-Li Lin *, Hui-Na Wu , Chien-Dai Chiang
1
1 2
Department of Obstetrics and Gynecology, Taipei City Hospital, and Institute of Health Policy and Management, College of Public Health, National Taiwan University, Taipei, Taiwan.
SUMMARY Objective: To assess adolescent pregnancy for demographic characteristics, obstetric morbidity, and birth outcome in Taipei City Hospitals. Materials and Methods: Registry data for 9,630 singleton births at 20 weeks or more of gestation at seven city hospitals in Taipei between January 2002 and June 2003 were studied. Mothers were divided into three groups by age: under 20 (n = 133 births; 1.4%); 20–34 (n = 8,035; 83.4%), and over 34 (n = 1,462; 15.2%). The overall registration rate was about 95%. Data were analyzed by Chi-squared, logistic regression, and ANOVA tests. Results: Education attainment in the teenage group was lower and the proportion who were single, had first parity, sought prenatal care after first trimester, and smoked were significantly higher. Obstetric complications were more common in this group in terms of antenatal anemia and precipitate labor, with adjusted odds ratios (ORs) of 2.2 (1.2–4.0) and 3.0 (1.5–6.2), but not in the frequency of prolonged labor, postpartum hemorrhage, abruptio placenta, or hypertensive disorder. However, rates were higher for stillbirth (adjusted OR, 2.8; 1.0–8.2) and small for gestational age (crude OR, 1.9; 1.2–3.2), resulting in the lowest mean birth weight of infants. No significant differences were demonstrated in frequency of prematurity, Apgar score, congenital anomalies, intensive care unit admission, or neonatal death. Conclusion: Teenage maternity is associated with general characteristics of social disadvantage and suboptimal outcome. We recommend education classes, focusing on the nutritional aspects of anemia correction, smoking cessation, and adequate preparation for birth. In addition, an integrated program is required, with social workers recruited to enhance family support. [Taiwanese J Obstet Gynecol 2005;44(3):258–263] Key Words: adolescent, birth outcome, pregnancy, teenage
Introduction Teenage pregnancy has long been associated with elevated risks of adverse reproductive outcome. In Taiwan, the fertility rate for women aged 15–19 years is 13 per 1,000 [1], which is higher than that in other
*Correspondence to: Dr. Chen-Li Lin, Department of Obstetrics and Gynecology, Taipei City Hospital, Women and Children’s Center, 12 Fujhou Street, Jhongjheng District, Taipei 100, Taiwan. E-mail: [email protected] Received: March 21, 2005 Revised: April 20, 2005 Accepted: April 26, 2005
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developed countries in Asia [2]. In addition, our teenage mothers have a lower reduction in the rate of delivering low birth weight (LBW) newborns compared with adult mothers in the last 20 years [3]. A report from the US Population Reference Bureau has shown that maternal mortality among women in this age group is twice as high as among their counterparts in their twenties [4]. As adolescent females are not yet completely grown, they are at greater risk of obstructed labor, which can lead to permanent injury or death for both the mother and infant. In a number of countries, the risk of death during the first year of life is 1.5 times higher for infants born to mothers under 20 years of age than for those born to mothers aged between 20 and 29 years [4].
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Teenage Maternity in Taipei
The literature shows that adolescent pregnancies, particularly in younger teens, have long been associated with increased rates of obstetric complications, including sexually transmitted infections, dystocia, premature delivery, LBW babies, and stillbirth [4–7]. Many of the complications are attributed to delay in prenatal care, poverty, and smoking. [5,6,8,9]. Teenage maternity is associated with a low education level and unmarried status, and such mothers tend to be more compromised by lower socioeconomic status in adult life (e.g. unemployment and unskilled occupation) [10,11], with serious consequences for family and offspring. Birth outcome varies by region [10] and depends on accessibility to education and health services. Some researchers suggest that pregnant teenagers are not a high-risk group if good prenatal care is provided [11]. Pregnancy under 16 years of age has extremely poor birth outcome [7,10]. In Taiwan, teenage mothers have higher rates of alcohol and nicotine consumption and inadequate prenatal care compared with their adult counterparts [12,13]. To effectively decrease our national infant mortality rate, we need to understand the current status of domestic teenage maternity, including maternal characteristics, obstetric complications, and birth outcome.
Materials and Methods Data collection Data were derived from the Pregnancy Risk Assessment Monitoring System Program, conducted by the Department of Health of the Taipei City Government and implemented in seven municipal hospitals. Pregnant women undergo a general health examination at the first prenatal visit and their records are entered into the database of this registration program. Relevant information at different stages of pregnancy are carefully collected and recorded by registered nurses and case managers in each hospital. This registration program is evaluated by the Department of Health annually, and registration rates reach 95% according to reported birth certificates. Complete information for 9,630 singleton births with gestational ages of at least 20 weeks was derived from the registration database of 10,067 reported deliveries from January 2002 to June 2003 (excluding 330 incomplete data sets and 107 multiple births).
Definitions Maternal age was defined as the age in complete years at the time of delivery. Antenatal anemia was defined as a hemoglobin of less than 12 mg/dL. Hypertensive
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disorder during pregnancy was diagnosed when systolic or diastolic blood pressure was more than 140 or 90 mmHg, respectively. Prolonged labor was defined by a latent phase of more than 20 hours for primigravida or more than 14 hours for multigravida, respectively. Precipitate labor was defined when delivery took place within 3 hours of the commencement of regular labor pains. Postpartum hemorrhage was diagnosed when total blood loss during labor (until postpartum) was more than 500 mL for normal spontaneous delivery (NSD) or more than 1 L for cesarean section. Stillbirth was defined as a fetus with no vital signs at birth or feeble signs that were extinguished within 1 hour of birth. Premature delivery was defined as birth at less than 37 weeks of gestation. Neonates with a weight of less than 2,500 g were considered LBW. Small for gestational age (SGA) was defined as a birth weight of less than the tenth percentile based on the Birth Weight Standards of Taiwan [14]. Congenital birth defects were diagnosed by the criteria of the Taiwanese Birth Defects Registration system.
Statistical analysis All registered data were analyzed using SPSS 10.0 software (SPSS Inc, Chicago, IL, USA). We used Chisquared and ANOVA tests to analyze differences in demographic characteristics, and logistic regression to calculate odds ratios (ORs) for pregnancy complications and birth outcomes, with a probability of 5% or less being considered statistically significant. Confounding factors including marital status, smoking and parity were adjusted for if the crude OR showed significance.
Results Demographic characteristics Demographic characteristics are presented in Table 1. Mothers aged under 20 years (n = 133) were compared to their adult counterparts aged 20–34 years (n = 8,035) and over 34 years (n = 1,462). A higher proportion of the teenage mothers were single (41.2%) than mothers in the other two groups (3.7% and 3.4%, respectively; p < 0.001) and were in their first pregnancy (85% vs 56.6% and 30.5%; p < 0.001). Mothers aged under 20 had higher rates of education to middle school or less (40.9%) than the other two groups (10.2% and 8.2%; p < 0.001). They also had lower rates of commencing antenatal care in the first trimester (55.5% vs 86.4% and 87.0%; p < 0.001). Furthermore, the smoking rate was 16.5% among this age group, significantly higher than among adult mothers (2.1% and 1.5%; p < 0.001).
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Table 1. Demographic characteristics of 9,630 singleton births among three maternal age groups* < 20 yr
20–34 yr
* 35 yr
Total
Distribution
01.4
83.4
15.2
100
Marital status Married Single
58.8 41.2
96.2 03.7
96.5 03.4
95.8 04.2
Parity 1 *2
85.0 15.0
56.6 43.4
30.5 69.5
53.0 47.0
Education Middle school or below High school College or above
40.9 59.1 0.
10.2 64.9 24.9
08.2 61.8 30.0
10.3 64.6 25.3
Prenatal care commencing in first trimester Yes 55.5 No 44.5
86.4 13.6
87.0 13.0
86.1 13.9
Smoking habit‡ Smoker Ex-smoker Non-smoker
02.1 04.3 93.6
01.5 02.7 95.8
02.2 04.2 93.6
p†
< 0.001
< 0.001
< 0.001
< 0.001
< 0.001 16.5 13.5 69.9
*All values are in %; †Chi-squared test; ‡smoking habit self-reported at first prenatal visit.
Table 2. Obstetric complications Total, n (%)
< 20 yr, %
20–34 yr, %
Delivery method NSD Cesarean section
5,979 (73.2) 2,185 (26.8)
82.0 18.0
Antenatal anemia Yes No
,406 (5.0) 7,762 (95.0)
Preterm labor (< 37 wk) Yes No
OR (95% CI)* Crude OR
Adjusted OR
73.1 26.9
0.6† (0.4–0.9)0
0.7 (0.4–1.0)
09.8 90.2
04.9 95.1
2.2† (1.2–3.9)0
2.2† (1.2–4.0)0
,394 (4.9) 7,700 (95.1)
04.7 95.3
04.9 95.1
0.9 (0.4–2.2)
Prolonged labor Yes No
,404 (4.9) 7,764 (95.1)
03.0 97.0
05.0 95.0
0.3 (0.2–1.6)
Precipitate labor Yes No
,283 (3.5) 7,885 (96.5)
07.5 92.5
03.4 96.6
2.4† (1.2–4.6)0
Postpartum hemorrhage Yes No
0,70 (0.9) 8,098 (99.1)
01.5 98.5
00.8 99.2
1.9 (0.5–7.8)
Abruptio placenta Yes No
0,45 (0.6) 8,123 (99.4)
01.5 98.5
00.5 99.5
03.1 (0.7–13.1)
Hypertension Yes No
,154 (1.9) 8,014 (98.1)
03.0 97.0
01.9 98.1
1.7 (0.6–4.7)
3.0‡ (1.5–6.2)0
*OR calculated by logistic regression analysis with age group 20–34 as reference followed by adjustment, if significant, with confounding factors including marital status, smoking, and parity; †p < 0.05; ‡p < 0.01. OR = odds ratio; CI = confidence interval; NSD = normal spontaneous delivery. Overall missing data less than 1%.
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Obstetric complications Teenage mothers, compared with mothers aged 20–34, had significantly higher rates of antenatal anemia (9.8% vs 4.9%; adjusted OR, 2.2) and precipitate labor (7.5% vs 3.4%) (Table 2). However, rates of cesarean section were lower than in those aged 20–34 (18.0% vs 26.9%; crude OR, 0.6; adjusted OR, 0.7). The frequency of prolonged labor, postpartum hemorrhage, abruptio placenta, and hypertensive disorder during pregnancy were not different between these two groups.
Birth outcomes Table 3 shows the birth outcomes. The stillbirth rate was significantly higher in teenage mothers than in those aged 20–34 (3.0% vs 0.9%; adjusted OR, 2.8). Among live births, teenage mothers had higher rates of SGA infants than mothers aged 20–34 (14.8% vs 8.3%; crude OR, 1.9; adjusted OR, 1.3). In terms of LBW, prematurity, low Apgar score, intensive care unit admission, birth defects, and neonatal death, there were no significant differences.
Mean birth weight among live births is shown in Table 4. Mothers aged under 20 delivered infants whose mean birth weight was the lowest of any group (3,031.8 g; p < 0.001); when compared with mean birth weight in mothers aged 25–29, this was 139 g lower.
Discussion In Taipei, the fertility rate among women aged 15–19 is 5 per 1,000 [1]. About 400 infants are born to adolescent mothers annually, with 10% of their infants having LBW [1,14]. Compared with Taipei’s maternal population, our study found similar prevalence rates of teenage birth, but with a lower rate of LBW infants [15], probably because it was conducted in community hospitals with few referral cases. Several reports recognize that younger teenage mothers have insufficient cognitive ability, lack family support, have immature psychosocial status, and have adverse habits such as tobacco or drug addiction [9,
Table 3. Birth outcomes Total, n (%)
< 20 yr, %
20–34 yr, %
Birth status Stillbirth Live birth
,074 (0.9) 8,094 (99.1)
03.0 97.0
Birth weight < 2,500 g Yes No
,397 (4.9) 7,696 (95.1)
SGA Yes No
OR (95% CI)* Crude OR
Adjusted OR
00.9 99.1
3.5† (1.3–9.8)0
2.8† (1.0–8.2)0
06.3 90.2
04.9 95.1
1.3 (0.6–2.7)
,667 (8.4) 7,408 (91.6)
14.8 85.2
08.3 91.7
1.9† (1.2–3.2)0
1-min Apgar score < 7 Yes No
,156 (1.9) 7,937 (98.1)
01.6 98.5
00.8 99.2
0.8 (0.2–3.3)
5-min Apgar score < 7 Yes No
,034 (0.4) 8,058 (99.6)
.0 100.0
00.4 99.6
—
ICU admission Yes No
,164 (2.0) 7,912 (98.0)
01.6 98.4
02.0 98.0
0.8 (0.2–3.1)
Birth defect Yes No
,114 (1.4) 7,980 (98.6)
02.3 97.7
01.4 98.6
1.6 (0.5–5.0)
Newborn death‡ Yes No
,009 (0.1) 8,085 (99.9)
.0 100.0
00.1 99.9
—
1.3 (0.8–2.2)
—
—
*OR calculated by logistic regression analysis with age group 20–34 as reference followed by adjustment, if significant, with confounding factors including marital status, smoking, and parity; †p < 0.05; ‡newborn infants died during hospitalization after birth. OR = odds ratio; CI = confidence interval; SGA = small for gestational age; ICU = intensive care unit. Overall missing data less than 1%.
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Table 4. Mean birth weight (BW) of newborns by maternal age group* Maternal age, yr ) 19 20–24 25–29 30–34 35–39 * 40 Missing data
n
Mean BW (g)
95% CI
Mean difference (g)
0,129 1,181 3,200 3,596 1,235 0,210 00,79
3,031.9 3,116.5 3,171.1 3,194.3 3,189.3 3,239.9
2,965.3–3,098.3 3,092.8–3,140.1 3,155.9–3,186.2 3,179.8–3,208.7 3,161.8–3,216.7 3,175.4–3,304.4
–139.3† 0–54.6† Reference 0023.2‡ 0018.2 0068.9‡
*Data analyzed by one way ANOVA and LSD post-hoc test; †p < 0.001; ‡p < 0.05. CI = confidence interval; LSD = least significant difference.
16]. But is this true in Taiwan? Our study indicates that, in general, it is: teenage mothers in Taipei had a higher incidence of single status, low educational attainment, delayed prenatal care, and smoking. These factors not only contribute to great difficulties in self-care and taking care of their offspring, but also increase the risk of adverse pregnancy outcomes [8]. Obviously, teenage mothers make greater demands on medical care, but lack of early or appropriate management is common. Tobacco is also an important risk factor during pregnancy, affecting both mother and fetus and resulting in a high rate of LBW infants [17,18]. In this study, our teenage mothers had a higher rate of tobacco exposure than their adult counterparts, so an anti-tobacco program aimed at pregnant teenagers should be instigated. Anemia, identified as a risk factor in recent national surveys in the USA and many developing countries, also affected adolescent pregnancy in our population. Pregnant teenagers have a higher iron requirement due to the concomitant impacts of growth, onset of menses, and the metabolic costs of pregnancy. However, the opportunities to acquire sufficient iron to buffer storage and to meet the demands of pregnancy are limited [19]. Thus, one of the recommendations from our study is iron supplementation for teenage mothers to prevent deficiency during pregnancy. There are some reports that pregnant teenagers have increased rates of maternal morbidity, including sexually transmitted disease, reduced maternal weight gain, dystocia, and prematurity [9,16]. However, in this study, we did not find a significant increase in maternal morbidity in prolonged labor, postpartum hemorrhage, abruptio placenta, or hypertensive disorder, possibly because this study was conducted in community hospitals with few referred cases. We also noted that teenage mothers had a higher chance of having precipitate labor. Though the cause was not clear, some physical factors and insufficient cognitive ability to prepare for delivery were thought to be involved, which deserve more attention by care
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providers. Based on these results, education classes emphasizing awareness of and preparations for delivery should be given to this population in the prenatal stage. Our results disagreed with those of some studies [5, 15,20]: there was no evidence supporting that adolescent pregnancy was associated with a higher incidence of adverse birth outcomes such as LBW, low Apgar score, ICU admission, birth defect, or neonatal death. However, we encountered more stillbirths and SGA infants in this age group, as previously reported [6]. Although there was no significant difference in LBW infants, we found that the incidence of SGA infants was higher, and that this age group had significantly the lowest mean infant birth weight. Research focused on younger teenagers, i.e. less than 16 years of age, found even worse obstetric outcomes than in those aged 16–19, probably due to biological immaturity and its effect on preterm labor [21]. To see if this holds true in our population, further studies are needed. In conclusion, teenage maternity is associated with general characteristics of social disadvantage and more pregnancy-related morbidity. Therefore, we recommend education programs focusing on the nutritional aspects of anemia correction, smoking cessation, and adequate preparation for birth. In addition, an integrated delivery system of care is required, with social workers recruited to enhance family support.
Acknowledgments We gratefully acknowledge support from the Department of Health, Taipei City Government, in Research Funding No. 910017-4-017, and all participating staff at Taipei City Hospitals.
References 1. The Ministry of the Interior, Republic of China, Taiwan and Fuchien Demographic Fact Book, Republic of China, 2003. Taiwan,
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R.O.C.: The Ministry of the Interior, Republic of China, 2003. 2. Population Division of the Department of Economic and Social Affairs of the United Nations Secretariat. World Population Prospects: The 2002 Revision and World Urbanization Prospects: The 2001 Revision. As found at http://esa.un.org/ unpp. 3. Lu TH, Sung FC, Li CY. Demographic characteristics and trends in the prevalence of low birth weight from singleton pregnancies in Taiwan. J Formos Med Assoc 2003;102:313–8. 4. Population Reference Bureau. The World’s Youth 2000. Washington, DC: Population Reference Bureau, 2001. 5. Smith GCS, Pell JP. Teenage pregnancy and risk of adverse perinatal outcomes associated with first and second births: population based retrospective cohort study. BMJ 2001;323: 476–80. 6. Yoder BA, Young MK. Neonatal outcomes of teenage pregnancy in a military population. Obstet Gynecol 1997;90:500–6. 7. Chandra PC, Schiavello HJ, Ravi B, Weinstein AG, Hook FB. Pregnancy outcomes in urban teenagers. Int J Gynecol Obstet 2002;79:117–22. 8. Olausson PM, Cnattingius S, Goldenberg RL. Determinants of poor pregnancy outcomes among teenagers in Sweden. Obstet Genecol 1997;89:451–7. 9. Elfenbein DS, Felice ME. Adolescent pregnancy. Pediatr Clin North Am 2003;50:781–800. 10. Olausson PO, Cnattingius S, Haglund B. Does the increased risk of preterm delivery in teenagers persist in pregnancies after the teenage period? Br J Obstet Gynaecol 2001;108: 721–5. 11. Wang RH, Wang HH, Hsu MT. Factors associated with
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adolescent pregnancy: a sample of Taiwanese female adolescents. Public Health Nurs 2003,20:33–41. 12. Wang CS, Chou P. Characteristics and outcomes of adolescent pregnancies in Kaohsiung county, Taiwan. J Formos Med Assoc 1999;6:415–21. 13. Li YT, Yin CS, Chan CC. Psychosocial risk factors of teenage pregnancy in eastern Taiwan. Chin Med J (Taipei) 1999;62: 425–30. 14. Department of OB/GYN, Chang Gung Memorial Hospital. Birth Weight Standards in Taiwan, 1990. Taipei: Chang Gung Memorial Hospital, 1990. 15. Lin CL, Wu HN, Chu JH, Chu CH. Preterm birth in Taipei City, 2001–2003. 14th Taiwan–Japan Symposium on Obstetric/ Gynecological Ultrasound and Perinatology, 2004. 16. Tsai TS, Chen JY, Lee MC. Reproductive outcomes and infant health in adolescent pregnancy in Taichung City. Acta Paediatr Taiwan 2001;42:151–7. 17. Samet JM, Yoon SY. Women and the Tobacco Epidemic: Challenges for the 21st Century. Geneva: World Health Organization, 2001. 18. Chen PC, Li CY, Lin RS, Sung FC. Maternal smoking, environmental tobacco smoking and low birth weight. Taiwan J Public Health 2002;21:321–8. 19. Bread JL. Iron requirements in adolescent females. J Nutr 2000;130:440S–2S. 20. Li YM, Fu CC. Maternal age and adverse pregnancy outcomes: analysis of birth records from 1997 to 1999 in Hualien County. Tzu Chi Med J 2001;13:95–103. 21. Births: final data for 2002. Natl Vit Stat Rep 2003;52:1–114. Available at: http://www.cdc.gov/nchs/data/nvsr/nvsr52/ nvsr52_10.pdf.
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C.L. Lin, et al
TEENAGE MATERNITY: A STUDY FROM SEVEN CITY HOSPITALS IN TAIPEI 1
1,2
Chen-Li Lin *, Hui-Na Wu , Chien-Dai Chiang
1
1 2
Department of Obstetrics and Gynecology, Taipei City Hospital, and Institute of Health Policy and Management, College of Public Health, National Taiwan University, Taipei, Taiwan.
SUMMARY Objective: To assess adolescent pregnancy for demographic characteristics, obstetric morbidity, and birth outcome in Taipei City Hospitals. Materials and Methods: Registry data for 9,630 singleton births at 20 weeks or more of gestation at seven city hospitals in Taipei between January 2002 and June 2003 were studied. Mothers were divided into three groups by age: under 20 (n = 133 births; 1.4%); 20–34 (n = 8,035; 83.4%), and over 34 (n = 1,462; 15.2%). The overall registration rate was about 95%. Data were analyzed by Chi-squared, logistic regression, and ANOVA tests. Results: Education attainment in the teenage group was lower and the proportion who were single, had first parity, sought prenatal care after first trimester, and smoked were significantly higher. Obstetric complications were more common in this group in terms of antenatal anemia and precipitate labor, with adjusted odds ratios (ORs) of 2.2 (1.2–4.0) and 3.0 (1.5–6.2), but not in the frequency of prolonged labor, postpartum hemorrhage, abruptio placenta, or hypertensive disorder. However, rates were higher for stillbirth (adjusted OR, 2.8; 1.0–8.2) and small for gestational age (crude OR, 1.9; 1.2–3.2), resulting in the lowest mean birth weight of infants. No significant differences were demonstrated in frequency of prematurity, Apgar score, congenital anomalies, intensive care unit admission, or neonatal death. Conclusion: Teenage maternity is associated with general characteristics of social disadvantage and suboptimal outcome. We recommend education classes, focusing on the nutritional aspects of anemia correction, smoking cessation, and adequate preparation for birth. In addition, an integrated program is required, with social workers recruited to enhance family support. [Taiwanese J Obstet Gynecol 2005;44(3):258–263] Key Words: adolescent, birth outcome, pregnancy, teenage
Introduction Teenage pregnancy has long been associated with elevated risks of adverse reproductive outcome. In Taiwan, the fertility rate for women aged 15–19 years is 13 per 1,000 [1], which is higher than that in other
*Correspondence to: Dr. Chen-Li Lin, Department of Obstetrics and Gynecology, Taipei City Hospital, Women and Children’s Center, 12 Fujhou Street, Jhongjheng District, Taipei 100, Taiwan. E-mail: [email protected] Received: March 21, 2005 Revised: April 20, 2005 Accepted: April 26, 2005
258
developed countries in Asia [2]. In addition, our teenage mothers have a lower reduction in the rate of delivering low birth weight (LBW) newborns compared with adult mothers in the last 20 years [3]. A report from the US Population Reference Bureau has shown that maternal mortality among women in this age group is twice as high as among their counterparts in their twenties [4]. As adolescent females are not yet completely grown, they are at greater risk of obstructed labor, which can lead to permanent injury or death for both the mother and infant. In a number of countries, the risk of death during the first year of life is 1.5 times higher for infants born to mothers under 20 years of age than for those born to mothers aged between 20 and 29 years [4].
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The literature shows that adolescent pregnancies, particularly in younger teens, have long been associated with increased rates of obstetric complications, including sexually transmitted infections, dystocia, premature delivery, LBW babies, and stillbirth [4–7]. Many of the complications are attributed to delay in prenatal care, poverty, and smoking. [5,6,8,9]. Teenage maternity is associated with a low education level and unmarried status, and such mothers tend to be more compromised by lower socioeconomic status in adult life (e.g. unemployment and unskilled occupation) [10,11], with serious consequences for family and offspring. Birth outcome varies by region [10] and depends on accessibility to education and health services. Some researchers suggest that pregnant teenagers are not a high-risk group if good prenatal care is provided [11]. Pregnancy under 16 years of age has extremely poor birth outcome [7,10]. In Taiwan, teenage mothers have higher rates of alcohol and nicotine consumption and inadequate prenatal care compared with their adult counterparts [12,13]. To effectively decrease our national infant mortality rate, we need to understand the current status of domestic teenage maternity, including maternal characteristics, obstetric complications, and birth outcome.
Materials and Methods Data collection Data were derived from the Pregnancy Risk Assessment Monitoring System Program, conducted by the Department of Health of the Taipei City Government and implemented in seven municipal hospitals. Pregnant women undergo a general health examination at the first prenatal visit and their records are entered into the database of this registration program. Relevant information at different stages of pregnancy are carefully collected and recorded by registered nurses and case managers in each hospital. This registration program is evaluated by the Department of Health annually, and registration rates reach 95% according to reported birth certificates. Complete information for 9,630 singleton births with gestational ages of at least 20 weeks was derived from the registration database of 10,067 reported deliveries from January 2002 to June 2003 (excluding 330 incomplete data sets and 107 multiple births).
Definitions Maternal age was defined as the age in complete years at the time of delivery. Antenatal anemia was defined as a hemoglobin of less than 12 mg/dL. Hypertensive
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disorder during pregnancy was diagnosed when systolic or diastolic blood pressure was more than 140 or 90 mmHg, respectively. Prolonged labor was defined by a latent phase of more than 20 hours for primigravida or more than 14 hours for multigravida, respectively. Precipitate labor was defined when delivery took place within 3 hours of the commencement of regular labor pains. Postpartum hemorrhage was diagnosed when total blood loss during labor (until postpartum) was more than 500 mL for normal spontaneous delivery (NSD) or more than 1 L for cesarean section. Stillbirth was defined as a fetus with no vital signs at birth or feeble signs that were extinguished within 1 hour of birth. Premature delivery was defined as birth at less than 37 weeks of gestation. Neonates with a weight of less than 2,500 g were considered LBW. Small for gestational age (SGA) was defined as a birth weight of less than the tenth percentile based on the Birth Weight Standards of Taiwan [14]. Congenital birth defects were diagnosed by the criteria of the Taiwanese Birth Defects Registration system.
Statistical analysis All registered data were analyzed using SPSS 10.0 software (SPSS Inc, Chicago, IL, USA). We used Chisquared and ANOVA tests to analyze differences in demographic characteristics, and logistic regression to calculate odds ratios (ORs) for pregnancy complications and birth outcomes, with a probability of 5% or less being considered statistically significant. Confounding factors including marital status, smoking and parity were adjusted for if the crude OR showed significance.
Results Demographic characteristics Demographic characteristics are presented in Table 1. Mothers aged under 20 years (n = 133) were compared to their adult counterparts aged 20–34 years (n = 8,035) and over 34 years (n = 1,462). A higher proportion of the teenage mothers were single (41.2%) than mothers in the other two groups (3.7% and 3.4%, respectively; p < 0.001) and were in their first pregnancy (85% vs 56.6% and 30.5%; p < 0.001). Mothers aged under 20 had higher rates of education to middle school or less (40.9%) than the other two groups (10.2% and 8.2%; p < 0.001). They also had lower rates of commencing antenatal care in the first trimester (55.5% vs 86.4% and 87.0%; p < 0.001). Furthermore, the smoking rate was 16.5% among this age group, significantly higher than among adult mothers (2.1% and 1.5%; p < 0.001).
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Table 1. Demographic characteristics of 9,630 singleton births among three maternal age groups* < 20 yr
20–34 yr
* 35 yr
Total
Distribution
01.4
83.4
15.2
100
Marital status Married Single
58.8 41.2
96.2 03.7
96.5 03.4
95.8 04.2
Parity 1 *2
85.0 15.0
56.6 43.4
30.5 69.5
53.0 47.0
Education Middle school or below High school College or above
40.9 59.1 0.
10.2 64.9 24.9
08.2 61.8 30.0
10.3 64.6 25.3
Prenatal care commencing in first trimester Yes 55.5 No 44.5
86.4 13.6
87.0 13.0
86.1 13.9
Smoking habit‡ Smoker Ex-smoker Non-smoker
02.1 04.3 93.6
01.5 02.7 95.8
02.2 04.2 93.6
p†
< 0.001
< 0.001
< 0.001
< 0.001
< 0.001 16.5 13.5 69.9
*All values are in %; †Chi-squared test; ‡smoking habit self-reported at first prenatal visit.
Table 2. Obstetric complications Total, n (%)
< 20 yr, %
20–34 yr, %
Delivery method NSD Cesarean section
5,979 (73.2) 2,185 (26.8)
82.0 18.0
Antenatal anemia Yes No
,406 (5.0) 7,762 (95.0)
Preterm labor (< 37 wk) Yes No
OR (95% CI)* Crude OR
Adjusted OR
73.1 26.9
0.6† (0.4–0.9)0
0.7 (0.4–1.0)
09.8 90.2
04.9 95.1
2.2† (1.2–3.9)0
2.2† (1.2–4.0)0
,394 (4.9) 7,700 (95.1)
04.7 95.3
04.9 95.1
0.9 (0.4–2.2)
Prolonged labor Yes No
,404 (4.9) 7,764 (95.1)
03.0 97.0
05.0 95.0
0.3 (0.2–1.6)
Precipitate labor Yes No
,283 (3.5) 7,885 (96.5)
07.5 92.5
03.4 96.6
2.4† (1.2–4.6)0
Postpartum hemorrhage Yes No
0,70 (0.9) 8,098 (99.1)
01.5 98.5
00.8 99.2
1.9 (0.5–7.8)
Abruptio placenta Yes No
0,45 (0.6) 8,123 (99.4)
01.5 98.5
00.5 99.5
03.1 (0.7–13.1)
Hypertension Yes No
,154 (1.9) 8,014 (98.1)
03.0 97.0
01.9 98.1
1.7 (0.6–4.7)
3.0‡ (1.5–6.2)0
*OR calculated by logistic regression analysis with age group 20–34 as reference followed by adjustment, if significant, with confounding factors including marital status, smoking, and parity; †p < 0.05; ‡p < 0.01. OR = odds ratio; CI = confidence interval; NSD = normal spontaneous delivery. Overall missing data less than 1%.
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Obstetric complications Teenage mothers, compared with mothers aged 20–34, had significantly higher rates of antenatal anemia (9.8% vs 4.9%; adjusted OR, 2.2) and precipitate labor (7.5% vs 3.4%) (Table 2). However, rates of cesarean section were lower than in those aged 20–34 (18.0% vs 26.9%; crude OR, 0.6; adjusted OR, 0.7). The frequency of prolonged labor, postpartum hemorrhage, abruptio placenta, and hypertensive disorder during pregnancy were not different between these two groups.
Birth outcomes Table 3 shows the birth outcomes. The stillbirth rate was significantly higher in teenage mothers than in those aged 20–34 (3.0% vs 0.9%; adjusted OR, 2.8). Among live births, teenage mothers had higher rates of SGA infants than mothers aged 20–34 (14.8% vs 8.3%; crude OR, 1.9; adjusted OR, 1.3). In terms of LBW, prematurity, low Apgar score, intensive care unit admission, birth defects, and neonatal death, there were no significant differences.
Mean birth weight among live births is shown in Table 4. Mothers aged under 20 delivered infants whose mean birth weight was the lowest of any group (3,031.8 g; p < 0.001); when compared with mean birth weight in mothers aged 25–29, this was 139 g lower.
Discussion In Taipei, the fertility rate among women aged 15–19 is 5 per 1,000 [1]. About 400 infants are born to adolescent mothers annually, with 10% of their infants having LBW [1,14]. Compared with Taipei’s maternal population, our study found similar prevalence rates of teenage birth, but with a lower rate of LBW infants [15], probably because it was conducted in community hospitals with few referral cases. Several reports recognize that younger teenage mothers have insufficient cognitive ability, lack family support, have immature psychosocial status, and have adverse habits such as tobacco or drug addiction [9,
Table 3. Birth outcomes Total, n (%)
< 20 yr, %
20–34 yr, %
Birth status Stillbirth Live birth
,074 (0.9) 8,094 (99.1)
03.0 97.0
Birth weight < 2,500 g Yes No
,397 (4.9) 7,696 (95.1)
SGA Yes No
OR (95% CI)* Crude OR
Adjusted OR
00.9 99.1
3.5† (1.3–9.8)0
2.8† (1.0–8.2)0
06.3 90.2
04.9 95.1
1.3 (0.6–2.7)
,667 (8.4) 7,408 (91.6)
14.8 85.2
08.3 91.7
1.9† (1.2–3.2)0
1-min Apgar score < 7 Yes No
,156 (1.9) 7,937 (98.1)
01.6 98.5
00.8 99.2
0.8 (0.2–3.3)
5-min Apgar score < 7 Yes No
,034 (0.4) 8,058 (99.6)
.0 100.0
00.4 99.6
—
ICU admission Yes No
,164 (2.0) 7,912 (98.0)
01.6 98.4
02.0 98.0
0.8 (0.2–3.1)
Birth defect Yes No
,114 (1.4) 7,980 (98.6)
02.3 97.7
01.4 98.6
1.6 (0.5–5.0)
Newborn death‡ Yes No
,009 (0.1) 8,085 (99.9)
.0 100.0
00.1 99.9
—
1.3 (0.8–2.2)
—
—
*OR calculated by logistic regression analysis with age group 20–34 as reference followed by adjustment, if significant, with confounding factors including marital status, smoking, and parity; †p < 0.05; ‡newborn infants died during hospitalization after birth. OR = odds ratio; CI = confidence interval; SGA = small for gestational age; ICU = intensive care unit. Overall missing data less than 1%.
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Table 4. Mean birth weight (BW) of newborns by maternal age group* Maternal age, yr ) 19 20–24 25–29 30–34 35–39 * 40 Missing data
n
Mean BW (g)
95% CI
Mean difference (g)
0,129 1,181 3,200 3,596 1,235 0,210 00,79
3,031.9 3,116.5 3,171.1 3,194.3 3,189.3 3,239.9
2,965.3–3,098.3 3,092.8–3,140.1 3,155.9–3,186.2 3,179.8–3,208.7 3,161.8–3,216.7 3,175.4–3,304.4
–139.3† 0–54.6† Reference 0023.2‡ 0018.2 0068.9‡
*Data analyzed by one way ANOVA and LSD post-hoc test; †p < 0.001; ‡p < 0.05. CI = confidence interval; LSD = least significant difference.
16]. But is this true in Taiwan? Our study indicates that, in general, it is: teenage mothers in Taipei had a higher incidence of single status, low educational attainment, delayed prenatal care, and smoking. These factors not only contribute to great difficulties in self-care and taking care of their offspring, but also increase the risk of adverse pregnancy outcomes [8]. Obviously, teenage mothers make greater demands on medical care, but lack of early or appropriate management is common. Tobacco is also an important risk factor during pregnancy, affecting both mother and fetus and resulting in a high rate of LBW infants [17,18]. In this study, our teenage mothers had a higher rate of tobacco exposure than their adult counterparts, so an anti-tobacco program aimed at pregnant teenagers should be instigated. Anemia, identified as a risk factor in recent national surveys in the USA and many developing countries, also affected adolescent pregnancy in our population. Pregnant teenagers have a higher iron requirement due to the concomitant impacts of growth, onset of menses, and the metabolic costs of pregnancy. However, the opportunities to acquire sufficient iron to buffer storage and to meet the demands of pregnancy are limited [19]. Thus, one of the recommendations from our study is iron supplementation for teenage mothers to prevent deficiency during pregnancy. There are some reports that pregnant teenagers have increased rates of maternal morbidity, including sexually transmitted disease, reduced maternal weight gain, dystocia, and prematurity [9,16]. However, in this study, we did not find a significant increase in maternal morbidity in prolonged labor, postpartum hemorrhage, abruptio placenta, or hypertensive disorder, possibly because this study was conducted in community hospitals with few referred cases. We also noted that teenage mothers had a higher chance of having precipitate labor. Though the cause was not clear, some physical factors and insufficient cognitive ability to prepare for delivery were thought to be involved, which deserve more attention by care
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providers. Based on these results, education classes emphasizing awareness of and preparations for delivery should be given to this population in the prenatal stage. Our results disagreed with those of some studies [5, 15,20]: there was no evidence supporting that adolescent pregnancy was associated with a higher incidence of adverse birth outcomes such as LBW, low Apgar score, ICU admission, birth defect, or neonatal death. However, we encountered more stillbirths and SGA infants in this age group, as previously reported [6]. Although there was no significant difference in LBW infants, we found that the incidence of SGA infants was higher, and that this age group had significantly the lowest mean infant birth weight. Research focused on younger teenagers, i.e. less than 16 years of age, found even worse obstetric outcomes than in those aged 16–19, probably due to biological immaturity and its effect on preterm labor [21]. To see if this holds true in our population, further studies are needed. In conclusion, teenage maternity is associated with general characteristics of social disadvantage and more pregnancy-related morbidity. Therefore, we recommend education programs focusing on the nutritional aspects of anemia correction, smoking cessation, and adequate preparation for birth. In addition, an integrated delivery system of care is required, with social workers recruited to enhance family support.
Acknowledgments We gratefully acknowledge support from the Department of Health, Taipei City Government, in Research Funding No. 910017-4-017, and all participating staff at Taipei City Hospitals.
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