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Obstetric outcome of immigrants from mainland China in Hong Kong
International Journal of Gynecology & Obstetrics 62 Ž1998. 223]227
Article
Obstetric outcome of immigrants from mainland China in Hong Kong T.N. Leung a,U , T.K. Lau a , V.J. Roacha , D. Wilsonb , M.S. Rogersa , A.M.Z. Chang a a
Department of Obstetrics and Gynaecology, Prince of Wales Hospital, The Chinese Uni¨ ersity of Hong Kong, Hong Kong b Faculty of Medicine, Uni¨ ersity of Sydney, Australia Received 13 February 1998; received in revised form 22 April 1998; accepted 8 May 1998
Abstract Objecti¨ e: To compare obstetric outcomes in two socio-economically distinct populations; illegal immigrants, who travelled across the Chinese border near term to deliver in Hong Kong between 1994 and 1996, and local Hong Kong residents. Methods: We identified two obstetric populations in our hospital with distinct social characteristics and patterns of antenatal care. A retrospective study of pregnancy outcome was conducted in these women. Results: When compared with Hong Kong residents, the illegal immigrants had a significantly lower incidence of antenatal complications, a lower requirement for obstetric intervention, and comparable obstetric outcome with the exception of a higher rate of delivery before arrival at hospital. Conclusion: Our findings were in contrast to previous reports, and contrary to our expectations. Obstetric outcome is multifactorial and previous assumptions about unbooked or socially disadvantaged patients should be re-evaluated. Q 1998 International Federation of Gynecology and Obstetrics Keywords: Obstetrics; Outcome; Socio-economic status
1. Introduction Hong Kong is located on the southern coast of
U
Corresponding author. Tel.: q852 2632 2810; fax: q852 2636 0008; e-mail: [email protected]
China and has a population of 6 million people, predominantly ethnic Chinese. The region has a relatively high per capita income, a low birth rate w1x, and enjoys a low maternal and perinatal mortality and morbidity by international standards w2x. The Prince of Wales Hospital is a university teaching hospital, located in Shatin in the New
0020-7292r98r$19.00 Q 1998 International Federation of Gynecology and Obstetrics PII S0020-7292Ž98.00100-3
224
T.N. Leung et al. r International Journal of Gynecology & Obstetrics 62 (1998) 223]227
Territories of Hong Kong. The rate of delivery at this center is approx. 7800 per year, the highest of any public hospital in Hong Kong. The hospital is also the closest obstetric unit to mainland China, approx. 30 km from the border. In recent years, an increasing number of women from the southern provinces of mainland China have crossed the border illegally near term, or in labor, with the intention of delivering their babies in Hong Kong. Late attendance, lack of antenatal care, and low social status are all recognized obstetric risk factors w3]5x. These women have received little, if any, antenatal care in Hong Kong, and difficulties associated with their illegal status presumably put them at greater risk of poor obstetric outcome. We therefore conducted a retrospective audit of the deliveries in our hospital between 1994 and 1996 to compare the obstetric outcome between illegal immigrants from China and local Hong Kong Chinese residents. 2. Methods The medical records of women delivered at the Prince of Wales Hospital, Hong Kong between 1994 and 1996 were retrieved from the obstetric database of the hospital and analyzed retrospectively. As Hong Kong law requires everyone to carry identification documents, the population can be classified into Hong Kong residents, those who entered Hong Kong legally on temporary permits, and those without proper documents who are classified as illegal immigrants. Only ethnic patients identified as Chinese on the database and classified as either Hong Kong residents or illegal immigrants were included in this study. Information retrieved included maternal factors Žage, height, weight at delivery, parity, antenatal complications including medical illness .; details of the labor Ždelivery before arrival of hospital, induction, cesarean section, instrumental or vaginal delivery and blood loss.; and fetal outcomes Žgestation at delivery, birth weight, sex, Apgar scores at 1 and 5 min, admission to the neonatal nursery, stillbirth and neonatal death.. Post-partum hemorrhage was defined as an estimated blood loss at delivery of ) 500 ml. All statistical analysis were performed by the
Statistical Package for the Social Sciences Version 7.0 ŽSPSS Inc, Illinois, USA.. Between group comparison was performed by independent t-test for continuous variables or by x 2 test for categorical data. A value of P- 0.05 was considered statistically significant. 3. Results There were 22 806 deliveries at the Prince of Wales Hospital between January 1994 and December 1996. Of the 22 806 women, 16 933 Ž74.2%. were Hong Kong residents, 2170 Ž9.5%. were illegal immigrants from mainland China, 1228 Ž5.4%. had a valid tourist visa, 866 Ž3.8%. had overstayed the period specified on their temporary visas, 798 Ž3.5%. were Vietnamese refugees from a detention center in Hong Kong and 811 Ž3.6%. were of non-Chinese ethnic origin. Among the 2170 illegal immigrants, 541 were delivered in 1994, 801 in 1995 and 828 in 1996. Illegal immigrants were significantly younger and of lower parity, but their height and weight were not different from those of the Hong Kong residents ŽTable 1.. Illegal immigrants had significantly lower incidence of all recorded complications including anemia, cardiac and thyroid disTable 1 Maternal characteristics, n Ž%. or n " S.D. P
Hong Kong residents n s 16933
Illegal immigrants n s 2170
744 Ž4.4%. 13 387 Ž79.1%. 280 Ž16.5%.
36 Ž1.7%. 2031 Ž93.6%. 101 Ž4.7%.
7403 Ž43.7%. 6321 Ž37.3%. 2355 Ž13.9%. 624 Ž3.7%. 230 Ž1.4%.
1086 Ž50.0%. 766 Ž35.3%. 208 Ž9.6%. 76 Ž3.5%. 34 Ž1.6%.
Height Žcm.
157.2" 5.5
157.4 " 4.9
0.08
Weight Žkg.
63.2" 9.9
63.4" 8.1
0.21
Age (years) F 20 21]34 G 35 Parity 0 1 2 3 G4
- 0.001
- 0.001
T.N. Leung et al. r International Journal of Gynecology & Obstetrics 62 (1998) 223]227
225
Table 2 Antenatal complications and characteristics of labor and delivery P
Hong Kong residents Ž n s 16 933.
Illegal immigrants Ž n s 2170.
Antenatal complications Anemia Cardiac disease Thyroid disease Antepartum hemorrhage Preeclampsia Gestational diabetes
n Ž%. 701 Ž4.1%. 239 Ž1.4%. 236 Ž1.4%. 311 Ž1.8%. 358 Ž2.1%. 1161 Ž6.9%.
n Ž%. 38 Ž1.75%. 3 Ž0.14%. 7 Ž0.32%. 12 Ž0.55%. 17 Ž0.78%. 16 Ž0.74%.
- 0.001 - 0.001 - 0.001 - 0.001 - 0.001 - 0.001
Labor Induction of labor Normal vaginal delivery Instrumental delivery Cesarean section Postpartum hemorrhage
n Ž%. 2276 Ž13.4%. 11 737 Ž69.3%. 2228 Ž13.2%. 2968 Ž17.5%. 948 Ž5.6%.
n Ž%. 219 Ž10.1%. 1714 Ž79%. 234 Ž10.8%. 222 Ž10.2%. 90 Ž4.2%.
- 0.001 - 0.001 - 0.001 - 0.001 0.0025
eases, pre-eclampsia, gestational diabetes, and antepartum hemorrhage ŽTable 2.. Significantly more illegal immigrants delivered before arrival at the obstetric unit, and they had significantly lower rates of induction of labor, instrumental delivery and cesarean section. Similar results were obtained when the analysis was repeated after excluding preterm deliveries. Gestation at delivery and neonatal outcome are summarized in Table 3. There were significantly more post-term pregnancies Ž) 42 weeks. amongst illegal immigrants and preterm deliveries Ž- 37 weeks. in Hong Kong residents. Babies from illegal immigrants were also significantly
heavier, but this difference disappeared when premature deliveries were excluded. There was no difference in the sex ratio between the two groups. No significant difference was found in Apgar scores or the incidence of stillbirth or neonatal death. However, significantly more infants born to Hong Kong residents required admission to the neonatal nursery for either observation or treatment. This difference remained after exclusion of preterm deliveries. As the higher rate of antenatal complications amongst Hong Kong residents might have contributed to poorer obstetric performance and
Table 3 Gestation at delivery and neonatal outcome
Gestation at delivery Žweeks. Delivery at - 37 weeks Delivery at ) 42 week Mean birth weight Žg. Apgar score at 1 min - 7 Apgar score at 5 min - 7 Admissions to neonatal unit Neonatal deaths Stillbirths
Hong Kong residents Ž n s 16 933.
Illegal immigrants Ž n s 2170.
P
38.9" 2.2 1307 Ž7.7%. 802 Ž4.7%. 3184 " 524 870 Ž5.1%. 80 Ž0.47%. 1853 Ž10.9%. 60 Ž0.35%. 66 Ž0.39%.
39.6" 1.7 78 Ž3.6%. 215 Ž9.9%. 3257 " 434 106 Ž4.8%. 5 Ž0.23%. 155 Ž7.1%. 4 Ž0.18%. 7 Ž0.32%.
- 0.001 - 0.001 - 0.001 - 0.001 0.504 0.055 - 0.001 0.099 0.316
226
T.N. Leung et al. r International Journal of Gynecology & Obstetrics 62 (1998) 223]227
neonatal outcomes, comparisons were repeated limiting the control group to those with no antenatal complications prior to term and the results remained the same. 4. Discussion The number of Chinese illegal immigrants attending for delivery in Hong Kong has increased in recent years. Most of these women are married to Hong Kong men. Although it may take years for these women to obtain a legal permit to immigrate to Hong Kong, their children, if delivered in the territory, are, by law, entitled to permanent residency. There are implications for the whole family as this may provide an alternate way for these women and their children to obtain permanent residency in Hong Kong. While some Chinese women are able to apply for tourist visas to deliver in Hong Kong, the women that we studied crossed the border illegally and were therefore classified as illegal immigrants. We are unable to comment on the amount or quality of antenatal care, if any, that these women had received in China. Our experience suggests that this is highly variable. However, it is reasonable to consider these patients at high risk of poor obstetric outcome in light of previous reports w3]5x. Relative to Hong Kong, these patients have low socio-economic status, are separated from their families, have poor social supports in Hong Kong and have limited antenatal care. Furthermore, the stress of crossing the border illegally near term presents an unfavorable risk factor for these women. Even if they choose to come to the territory before term, their status as illegal immigrants precludes them from regular antenatal care. Finally, they arrive for delivery unbooked, a factor reported previously as associated with unfavorable obstetric outcome w6x. Our results are contrary to those previously reported. Apart from a higher rate of delivery before arrival at hospital, all pregnancy and fetal outcome measures amongst the illegal immigrants were found to be similar or better than that of the local Hong Kong population. The illegal immigrants in our study were younger, with a higher percentage of nulliparous women, than the
Hong Kong residents. A higher rate of nulliparity could be partly explained by a younger population. The illegal immigrant group had a significantly lower incidence of antenatal complications, possibly related to the unusual characteristics of this group, who only came for delivery at term. Those who were medically unfit may have encountered difficulty crossing the border. Under-reporting of medical illness should also be considered. While data from Hong Kong Chinese were collected from their antenatal records, information from the illegal immigrants was restricted to the patient’s own report. The lower incidence of preterm delivery could be explained by the fact that most of these patients would only attempt to enter Hong Kong at or near to term, leading to a selection bias. The higher incidence of antenatal complications and preterm deliveries amongst the Hong Kong Chinese may partly explain the increased rate of medical intervention, with a higher incidence of labor induction, instrumental delivery and cesarean section. The high incidence of postterm delivery of 9.9% among the illegal immigrants is most likely a result of inaccurate dating of pregnancy and could be related to the desire of these women to deliver in Hong Kong. The diagnosis of post-term pregnancy, being an indication for induction of labor, would prevent deportation prior to delivery. Therefore some of the date errors may be deliberate falsification. Desire to avoid detection by the authorities may also account for the finding that illegal immigrants had a significantly higher rate of babies born before arrival at the hospital. Although there was no evidence that fetal outcome was worse in this group, the number of cases was too few to draw any conclusions. Previous studies, which have examined the relationship between obstetric outcome and social disadvantage, have also reported findings contrary to their expectations. Versi et al. w7x reviewed the obstetric outcome of Bangladeshi women in East London. They found that the Bangladeshis, though relatively poor and, therefore, classified as high-risk, had outcomes that were at least as good, if not better, than the overall British figure.
T.N. Leung et al. r International Journal of Gynecology & Obstetrics 62 (1998) 223]227
Positive birth outcomes were also reported from a study in New Mexico w8x, where Hispanic women, who were assumed to be at high risk for poor pregnancy outcome, had rates of low birth weight and infant mortality below the average for Northern Americans. The presentation to the labor ward of an unbooked, illegal immigrant mother places great stress on the staff. Because of limited information regarding their antenatal history, these patients are classified as high-risk, possibly influencing the care that they receive. This may have contributed to their good obstetric outcome. Our aim is to report the obstetric outcome of two socially distinct populations. We are aware of certain limitations and selection bias in this study. As the study is retrospective and data retrieval is limited, information on issues, such as nutritional status, family income, exact amount of antenatal care and the rigor of the illegal immigration process is lacking. With these limitations in mind, we found that, in contrast to previous reports and contrary to our expectations, the unbooked and socially-disadvantaged illegal immigrants from China have maternal and neonatal outcomes comparable to that of socially-advantaged Hong Kong residents, apart from a higher incidence of delivery before arrival at hospital. The results of this study may be useful for those obstetric units who are catering to a large number of illegal immigrants who just come for delivery without prior antenatal booking or care.
227
Acknowledgements The participation of Miss Diana Wilson in this study was supported by a scholarship from the Sydney Tapping Bequest, Postgraduate Committee in Medicine, The University of Sydney. References w1x Department of Health. Annual Departmental report ŽFinancial year 1993]94.. Government printer, Hong Kong, table 12, page 41. w2x Duthie SJ, Lee CP, Ma HK. Maternal mortality in Hong Kong. Br J Obstet Gynaecol 1994;101:906]907. w3x Ryan GM, Sweeney PJ, Solola AS. Prenatal care and pregnancy outcome. Am J Obstet Gynecol 1980;137: 876]881. w4x Blondel B, Dutilh P, Delour M, Uzan S. Poor antenatal care and pregnancy outcome. Eur J Obstet Gynaecol 1993;50:191]196. w5x Kaunitz AM, Spence C, Danielson TS, Rochat RW, Grimes DA. Perinatal and maternal mortality in a religious group avoiding obstetric care. Am J Obstet Gynecol 1984;150:826]831. w6x Keeping JD, Chang A, Morrison J, Esler EJ. Poor antenatal attendance and obstetric performance. Aust N Z J Obstet Gynaecol 1980;20:139]143. w7x Versi E, Ka LL, Chia P, Seddon G. Obstetric outcome of Bangladeshi women in East London. Br J Obstet Gynaecol 1995;102:630]637. w8x Albers LL. Clues to positive birth outcomes in New Mexico. J Nurse Midwifery 1994;39:273]277.
Article
Obstetric outcome of immigrants from mainland China in Hong Kong T.N. Leung a,U , T.K. Lau a , V.J. Roacha , D. Wilsonb , M.S. Rogersa , A.M.Z. Chang a a
Department of Obstetrics and Gynaecology, Prince of Wales Hospital, The Chinese Uni¨ ersity of Hong Kong, Hong Kong b Faculty of Medicine, Uni¨ ersity of Sydney, Australia Received 13 February 1998; received in revised form 22 April 1998; accepted 8 May 1998
Abstract Objecti¨ e: To compare obstetric outcomes in two socio-economically distinct populations; illegal immigrants, who travelled across the Chinese border near term to deliver in Hong Kong between 1994 and 1996, and local Hong Kong residents. Methods: We identified two obstetric populations in our hospital with distinct social characteristics and patterns of antenatal care. A retrospective study of pregnancy outcome was conducted in these women. Results: When compared with Hong Kong residents, the illegal immigrants had a significantly lower incidence of antenatal complications, a lower requirement for obstetric intervention, and comparable obstetric outcome with the exception of a higher rate of delivery before arrival at hospital. Conclusion: Our findings were in contrast to previous reports, and contrary to our expectations. Obstetric outcome is multifactorial and previous assumptions about unbooked or socially disadvantaged patients should be re-evaluated. Q 1998 International Federation of Gynecology and Obstetrics Keywords: Obstetrics; Outcome; Socio-economic status
1. Introduction Hong Kong is located on the southern coast of
U
Corresponding author. Tel.: q852 2632 2810; fax: q852 2636 0008; e-mail: [email protected]
China and has a population of 6 million people, predominantly ethnic Chinese. The region has a relatively high per capita income, a low birth rate w1x, and enjoys a low maternal and perinatal mortality and morbidity by international standards w2x. The Prince of Wales Hospital is a university teaching hospital, located in Shatin in the New
0020-7292r98r$19.00 Q 1998 International Federation of Gynecology and Obstetrics PII S0020-7292Ž98.00100-3
224
T.N. Leung et al. r International Journal of Gynecology & Obstetrics 62 (1998) 223]227
Territories of Hong Kong. The rate of delivery at this center is approx. 7800 per year, the highest of any public hospital in Hong Kong. The hospital is also the closest obstetric unit to mainland China, approx. 30 km from the border. In recent years, an increasing number of women from the southern provinces of mainland China have crossed the border illegally near term, or in labor, with the intention of delivering their babies in Hong Kong. Late attendance, lack of antenatal care, and low social status are all recognized obstetric risk factors w3]5x. These women have received little, if any, antenatal care in Hong Kong, and difficulties associated with their illegal status presumably put them at greater risk of poor obstetric outcome. We therefore conducted a retrospective audit of the deliveries in our hospital between 1994 and 1996 to compare the obstetric outcome between illegal immigrants from China and local Hong Kong Chinese residents. 2. Methods The medical records of women delivered at the Prince of Wales Hospital, Hong Kong between 1994 and 1996 were retrieved from the obstetric database of the hospital and analyzed retrospectively. As Hong Kong law requires everyone to carry identification documents, the population can be classified into Hong Kong residents, those who entered Hong Kong legally on temporary permits, and those without proper documents who are classified as illegal immigrants. Only ethnic patients identified as Chinese on the database and classified as either Hong Kong residents or illegal immigrants were included in this study. Information retrieved included maternal factors Žage, height, weight at delivery, parity, antenatal complications including medical illness .; details of the labor Ždelivery before arrival of hospital, induction, cesarean section, instrumental or vaginal delivery and blood loss.; and fetal outcomes Žgestation at delivery, birth weight, sex, Apgar scores at 1 and 5 min, admission to the neonatal nursery, stillbirth and neonatal death.. Post-partum hemorrhage was defined as an estimated blood loss at delivery of ) 500 ml. All statistical analysis were performed by the
Statistical Package for the Social Sciences Version 7.0 ŽSPSS Inc, Illinois, USA.. Between group comparison was performed by independent t-test for continuous variables or by x 2 test for categorical data. A value of P- 0.05 was considered statistically significant. 3. Results There were 22 806 deliveries at the Prince of Wales Hospital between January 1994 and December 1996. Of the 22 806 women, 16 933 Ž74.2%. were Hong Kong residents, 2170 Ž9.5%. were illegal immigrants from mainland China, 1228 Ž5.4%. had a valid tourist visa, 866 Ž3.8%. had overstayed the period specified on their temporary visas, 798 Ž3.5%. were Vietnamese refugees from a detention center in Hong Kong and 811 Ž3.6%. were of non-Chinese ethnic origin. Among the 2170 illegal immigrants, 541 were delivered in 1994, 801 in 1995 and 828 in 1996. Illegal immigrants were significantly younger and of lower parity, but their height and weight were not different from those of the Hong Kong residents ŽTable 1.. Illegal immigrants had significantly lower incidence of all recorded complications including anemia, cardiac and thyroid disTable 1 Maternal characteristics, n Ž%. or n " S.D. P
Hong Kong residents n s 16933
Illegal immigrants n s 2170
744 Ž4.4%. 13 387 Ž79.1%. 280 Ž16.5%.
36 Ž1.7%. 2031 Ž93.6%. 101 Ž4.7%.
7403 Ž43.7%. 6321 Ž37.3%. 2355 Ž13.9%. 624 Ž3.7%. 230 Ž1.4%.
1086 Ž50.0%. 766 Ž35.3%. 208 Ž9.6%. 76 Ž3.5%. 34 Ž1.6%.
Height Žcm.
157.2" 5.5
157.4 " 4.9
0.08
Weight Žkg.
63.2" 9.9
63.4" 8.1
0.21
Age (years) F 20 21]34 G 35 Parity 0 1 2 3 G4
- 0.001
- 0.001
T.N. Leung et al. r International Journal of Gynecology & Obstetrics 62 (1998) 223]227
225
Table 2 Antenatal complications and characteristics of labor and delivery P
Hong Kong residents Ž n s 16 933.
Illegal immigrants Ž n s 2170.
Antenatal complications Anemia Cardiac disease Thyroid disease Antepartum hemorrhage Preeclampsia Gestational diabetes
n Ž%. 701 Ž4.1%. 239 Ž1.4%. 236 Ž1.4%. 311 Ž1.8%. 358 Ž2.1%. 1161 Ž6.9%.
n Ž%. 38 Ž1.75%. 3 Ž0.14%. 7 Ž0.32%. 12 Ž0.55%. 17 Ž0.78%. 16 Ž0.74%.
- 0.001 - 0.001 - 0.001 - 0.001 - 0.001 - 0.001
Labor Induction of labor Normal vaginal delivery Instrumental delivery Cesarean section Postpartum hemorrhage
n Ž%. 2276 Ž13.4%. 11 737 Ž69.3%. 2228 Ž13.2%. 2968 Ž17.5%. 948 Ž5.6%.
n Ž%. 219 Ž10.1%. 1714 Ž79%. 234 Ž10.8%. 222 Ž10.2%. 90 Ž4.2%.
- 0.001 - 0.001 - 0.001 - 0.001 0.0025
eases, pre-eclampsia, gestational diabetes, and antepartum hemorrhage ŽTable 2.. Significantly more illegal immigrants delivered before arrival at the obstetric unit, and they had significantly lower rates of induction of labor, instrumental delivery and cesarean section. Similar results were obtained when the analysis was repeated after excluding preterm deliveries. Gestation at delivery and neonatal outcome are summarized in Table 3. There were significantly more post-term pregnancies Ž) 42 weeks. amongst illegal immigrants and preterm deliveries Ž- 37 weeks. in Hong Kong residents. Babies from illegal immigrants were also significantly
heavier, but this difference disappeared when premature deliveries were excluded. There was no difference in the sex ratio between the two groups. No significant difference was found in Apgar scores or the incidence of stillbirth or neonatal death. However, significantly more infants born to Hong Kong residents required admission to the neonatal nursery for either observation or treatment. This difference remained after exclusion of preterm deliveries. As the higher rate of antenatal complications amongst Hong Kong residents might have contributed to poorer obstetric performance and
Table 3 Gestation at delivery and neonatal outcome
Gestation at delivery Žweeks. Delivery at - 37 weeks Delivery at ) 42 week Mean birth weight Žg. Apgar score at 1 min - 7 Apgar score at 5 min - 7 Admissions to neonatal unit Neonatal deaths Stillbirths
Hong Kong residents Ž n s 16 933.
Illegal immigrants Ž n s 2170.
P
38.9" 2.2 1307 Ž7.7%. 802 Ž4.7%. 3184 " 524 870 Ž5.1%. 80 Ž0.47%. 1853 Ž10.9%. 60 Ž0.35%. 66 Ž0.39%.
39.6" 1.7 78 Ž3.6%. 215 Ž9.9%. 3257 " 434 106 Ž4.8%. 5 Ž0.23%. 155 Ž7.1%. 4 Ž0.18%. 7 Ž0.32%.
- 0.001 - 0.001 - 0.001 - 0.001 0.504 0.055 - 0.001 0.099 0.316
226
T.N. Leung et al. r International Journal of Gynecology & Obstetrics 62 (1998) 223]227
neonatal outcomes, comparisons were repeated limiting the control group to those with no antenatal complications prior to term and the results remained the same. 4. Discussion The number of Chinese illegal immigrants attending for delivery in Hong Kong has increased in recent years. Most of these women are married to Hong Kong men. Although it may take years for these women to obtain a legal permit to immigrate to Hong Kong, their children, if delivered in the territory, are, by law, entitled to permanent residency. There are implications for the whole family as this may provide an alternate way for these women and their children to obtain permanent residency in Hong Kong. While some Chinese women are able to apply for tourist visas to deliver in Hong Kong, the women that we studied crossed the border illegally and were therefore classified as illegal immigrants. We are unable to comment on the amount or quality of antenatal care, if any, that these women had received in China. Our experience suggests that this is highly variable. However, it is reasonable to consider these patients at high risk of poor obstetric outcome in light of previous reports w3]5x. Relative to Hong Kong, these patients have low socio-economic status, are separated from their families, have poor social supports in Hong Kong and have limited antenatal care. Furthermore, the stress of crossing the border illegally near term presents an unfavorable risk factor for these women. Even if they choose to come to the territory before term, their status as illegal immigrants precludes them from regular antenatal care. Finally, they arrive for delivery unbooked, a factor reported previously as associated with unfavorable obstetric outcome w6x. Our results are contrary to those previously reported. Apart from a higher rate of delivery before arrival at hospital, all pregnancy and fetal outcome measures amongst the illegal immigrants were found to be similar or better than that of the local Hong Kong population. The illegal immigrants in our study were younger, with a higher percentage of nulliparous women, than the
Hong Kong residents. A higher rate of nulliparity could be partly explained by a younger population. The illegal immigrant group had a significantly lower incidence of antenatal complications, possibly related to the unusual characteristics of this group, who only came for delivery at term. Those who were medically unfit may have encountered difficulty crossing the border. Under-reporting of medical illness should also be considered. While data from Hong Kong Chinese were collected from their antenatal records, information from the illegal immigrants was restricted to the patient’s own report. The lower incidence of preterm delivery could be explained by the fact that most of these patients would only attempt to enter Hong Kong at or near to term, leading to a selection bias. The higher incidence of antenatal complications and preterm deliveries amongst the Hong Kong Chinese may partly explain the increased rate of medical intervention, with a higher incidence of labor induction, instrumental delivery and cesarean section. The high incidence of postterm delivery of 9.9% among the illegal immigrants is most likely a result of inaccurate dating of pregnancy and could be related to the desire of these women to deliver in Hong Kong. The diagnosis of post-term pregnancy, being an indication for induction of labor, would prevent deportation prior to delivery. Therefore some of the date errors may be deliberate falsification. Desire to avoid detection by the authorities may also account for the finding that illegal immigrants had a significantly higher rate of babies born before arrival at the hospital. Although there was no evidence that fetal outcome was worse in this group, the number of cases was too few to draw any conclusions. Previous studies, which have examined the relationship between obstetric outcome and social disadvantage, have also reported findings contrary to their expectations. Versi et al. w7x reviewed the obstetric outcome of Bangladeshi women in East London. They found that the Bangladeshis, though relatively poor and, therefore, classified as high-risk, had outcomes that were at least as good, if not better, than the overall British figure.
T.N. Leung et al. r International Journal of Gynecology & Obstetrics 62 (1998) 223]227
Positive birth outcomes were also reported from a study in New Mexico w8x, where Hispanic women, who were assumed to be at high risk for poor pregnancy outcome, had rates of low birth weight and infant mortality below the average for Northern Americans. The presentation to the labor ward of an unbooked, illegal immigrant mother places great stress on the staff. Because of limited information regarding their antenatal history, these patients are classified as high-risk, possibly influencing the care that they receive. This may have contributed to their good obstetric outcome. Our aim is to report the obstetric outcome of two socially distinct populations. We are aware of certain limitations and selection bias in this study. As the study is retrospective and data retrieval is limited, information on issues, such as nutritional status, family income, exact amount of antenatal care and the rigor of the illegal immigration process is lacking. With these limitations in mind, we found that, in contrast to previous reports and contrary to our expectations, the unbooked and socially-disadvantaged illegal immigrants from China have maternal and neonatal outcomes comparable to that of socially-advantaged Hong Kong residents, apart from a higher incidence of delivery before arrival at hospital. The results of this study may be useful for those obstetric units who are catering to a large number of illegal immigrants who just come for delivery without prior antenatal booking or care.
227
Acknowledgements The participation of Miss Diana Wilson in this study was supported by a scholarship from the Sydney Tapping Bequest, Postgraduate Committee in Medicine, The University of Sydney. References w1x Department of Health. Annual Departmental report ŽFinancial year 1993]94.. Government printer, Hong Kong, table 12, page 41. w2x Duthie SJ, Lee CP, Ma HK. Maternal mortality in Hong Kong. Br J Obstet Gynaecol 1994;101:906]907. w3x Ryan GM, Sweeney PJ, Solola AS. Prenatal care and pregnancy outcome. Am J Obstet Gynecol 1980;137: 876]881. w4x Blondel B, Dutilh P, Delour M, Uzan S. Poor antenatal care and pregnancy outcome. Eur J Obstet Gynaecol 1993;50:191]196. w5x Kaunitz AM, Spence C, Danielson TS, Rochat RW, Grimes DA. Perinatal and maternal mortality in a religious group avoiding obstetric care. Am J Obstet Gynecol 1984;150:826]831. w6x Keeping JD, Chang A, Morrison J, Esler EJ. Poor antenatal attendance and obstetric performance. Aust N Z J Obstet Gynaecol 1980;20:139]143. w7x Versi E, Ka LL, Chia P, Seddon G. Obstetric outcome of Bangladeshi women in East London. Br J Obstet Gynaecol 1995;102:630]637. w8x Albers LL. Clues to positive birth outcomes in New Mexico. J Nurse Midwifery 1994;39:273]277.