doi:10.1111/jog.12662
J. Obstet. Gynaecol. Res. Vol. 41, No. 7: 1003–1008, July 2015
Adverse pregnancy outcome in patients with low pregnancy-associated plasma protein-A: The Indian Experience Sangeeta Gupta1, Manisha Goyal2, Deepti Verma3, Anjana Sharma2, Namita Bharadwaj2, Madhulika Kabra4 and Seema Kapoor2 1
Division of Fetal Medicine, Department of Obstetrics & Gynecology, 3Department of Obstetrics & Gynecology, 2Division of Genetics & Metabolism, Department of Pediatrics, Maulana Azad Medical College, 4Division of Genetics, Department Of Pediatrics, All India Institute Of Medical Sciences, New Delhi, India
Abstract Aim: The aim of our study was to examine the association of low pregnancy-associated plasma protein-A (PAPP-A) with adverse pregnancy outcome. Material and Methods: A total of 1640 consecutive pregnant women between 9+5 and 13+6 weeks of pregnancy were recruited. One hundred and thirty women with PAPP-A levels < 0.4 multiple of median were followed till delivery and the outcome information was obtained for fetal loss, birthweight, growth restriction, preterm birth, reduced liquor and development of pre-eclampsia. Results: During the study period, 130 (7.92%) women had low PAPP-A and were considered as cases and 200 women with normal PAPP-A were controls. Intrauterine growth restriction was observed in 28 (21.54%) cases as compared to 10 (5%) controls. Pre-eclampsia presented in 24 (18.46%) cases and in 18 (9%) controls. Twenty (15.38%) cases had preterm delivery compared to 12 (6%) controls. Fifty-six (43.08%) cases delivered lowbirthweight babies compared to 22 (11%) controls. Thus, the incidence of intrauterine growth restriction, preterm birth and low birthweight was significantly more in the cases as compared to the control group. Conclusions: PAPP-A is a valuable analyte for predicting risk of adverse pregnancy outcome and women with low serum PAPP-A levels would benefit from closer surveillance. Key words: fetal loss, intrauterine growth restriction, pregnancy outcome, pre-eclampsia, preterm birth.
Introduction Maternal serum pregnancy-associated plasma protein-A (PAPP-A) has been widely used in conjunction with free β-human chorionic gonadotrophin (hCG) level and nuchal translucency on ultrasound in firsttrimester screening to calculate the risk for trisomy 21
and other fetal aneuploidies. This robust marker physiologically is highly expressed in the syncytiotrophoblast of the placenta, which is the main source of circulating PAPP-A in pregnancy.1 It is basically akin to insulin-like growth factor binding protein-4 (IGFBP-4), which facilitates the breakdown of this protein resulting in a release of free insulin-like growth factor (IGF).2
Received: July 3 2014. Accepted: November 5 2014. Reprint request to: Dr Seema Kapoor, Division of Genetics & Metabolism, Department of Pediatrics, Maulana Azad Medical College, New Delhi, India. Email: [email protected] S.K. and S.G. conceived the idea of the project, D.V. recruited the patients, N.B. and A.S. applied the tests. M.G. helped in analysis of data and writing the manuscript. M.K. critically reviewed the manuscript. S.K. finally critically reviewed the manuscript and will actas guarantor for the paper.
© 2015 The Authors Journal of Obstetrics and Gynaecology Research © 2015 Japan Society of Obstetrics and Gynecology
1003
S. Gupta et al.
Locally synthesized IGF play an important role in promoting cellular mitosis and differentiation and in the control of trophoblastic invasion of the deciduas.3 Their role in the control of fetal growth is important as they regulate the uptake of amino acids and glucose in the trophoblast.4 Low levels of maternal serum PAPP-A are thought to be representative of decreased levels of PAPP-A at a local level and this translates to low levels of active IGF. Thus, impaired level of free IGF affecting the fetal growth may reflect other adverse pregnancy complications, such as stillbirth, intrauterine growth restriction (IUGR), preeclampsia (PE) and preterm labour.3,5 The predictably early detection of low first-trimester PAPP-A levels might identify women at high risk, help to triage the efforts of obstetricians in a busy outdoor clinic and augment efforts in planning of prenatal care. Thus we propose that in a country where insurance does not pay for a child with intellectual disability, preventive strategies may be the only option of preventing births of children with trisomies. Furthermore, if a serum marker can direct attention to a cohort who require strict surveillance, it would add significant value in its implementation. We present our experience with utility of low PAPP-A as an important marker in a north Indian cohort and discuss its utility in a resource-poor country.
Methods We enrolled all consecutive pregnant women presenting to the antenatal clinic of the Department of Obstetrics and Gynecology between 9+5 and 13+6 weeks of pregnancy. The aim of our study was to determine the association of low PAPP-A levels with adverse pregnancy outcome. The objective of the study was to correlate low PAPP-A with stillbirth, IUGR, PE and preterm labor. The gestational age at the time of blood sampling was calculated by crown–rump length in case a first trimester ultrasound was available and by date of last menstrual period if ultrasound was not available and the cycles were regular. Patient’s exact age, weight, gestation age by last menstrual period, presence of diabetes mellitus, hypertension or cardiovascular disease and history of any child with Down syndrome or any other genetic disease were determined. Smoking status was also determined, even though it is uncommon in India. Upon recruitment, the demographic characteristics were noted. Patients were given an informed consent form and a patient information sheet in the vernacular
1004
language of both Hindi and Urdu about the risk of fetal aneuploidies. The informed consent was directed to her spouse if she was illiterate or failed to conceive the concept of risk. Three to four milliliters of venous sample was collected. Serum was stored in batches of 80 at −20°C till analysis was done and this was always completed within the timeframe of action, which was usually 1.5–2 weeks. Testing was done by timeresolved fluorometry using kits manufactured by M/S Perkin Elmer. Coefficient of variation of less than 5% of the test was taken as acceptable. The markers evaluated in the first trimester were PAPP-A and free β-hCG. Nuchal translucency and crown–rump length were assessed by a single trained sonographer blinded to the results of the biochemical testing. The risk for trisomy 21,18,13 was calculated by in-house Lifecycle software version 3.2 based risk, which was generated for fetal aneuploidies from the pregnant woman’s ‘a priori age risk’ and the likelihood rates of the distribution of biochemical markers and/or nuchal translucency. The report contained both individual values of the analytes and their values modified as multiples of median (MoM). An MoM value of 1 meant that the marker level was equal to the median level for an unaffected pregnancy with the specified gestational age, maternal weight, ethnicity and smoking status while a value of 2 meant that the marker level was twice as high as the median level for an unaffected pregnancy with the specified gestational age, maternal weight, ethnicity and smoking status. All women with PAPP-A levels less than 0.4 MoM of first-trimester biochemical screening were selected as cases and women with similar gestational age and with normal serum PAPP-A levels were taken as control. Values of 0.4 MoM were taken as this value had previously reported with adverse pregnancy outcome.6 The Down syndrome risk was calculated and the cut-off value taken in the first trimester for offering invasive testing was 1:50. Genetic counseling was provided and those with a positive result were offered chorionic villous sampling or amniocentesis depending upon the patient’s choice and the gestational age at which she returned after counseling. Each participant received a study protocol and was instructed to bring it to every appointment during pregnancy, including the stay at the delivery ward. The subjects in the whole study group were followed as per the hospital protocols. Monthly follow-up was done for outdoor clinic patients and daily follow-up was done for admitted patients. Clinical management of the individual pregnancies, including the use of steroids,
© 2015 The Authors Journal of Obstetrics and Gynaecology Research © 2015 Japan Society of Obstetrics and Gynecology
Pregnancy outcome with low PAPP-A
tocolysis, additional ultrasounds or iatrogenic premature delivery, was left to independent attending physicians. Outcome information was obtained by antenatal records of recruited patients for spontaneous fetal loss, termination of pregnancy, small-for-gestational-age (SGA) birth, preterm birth, IUGR, reduced liquor on ultrasonography and development of PE. All the participants detected with major ultrasonic or chromosomal abnormality, women with insulin-dependent diabetes mellitus, chronic hypertension, cardiac disorders, renal disorders, multiple gestation or who had a self-motivated pregnancy termination were excluded. All of these pregnancies were followed till delivery and the results were obtained. The gestational age at delivery, neonatal birthweight, Apgar score, malformations and Ballard’s score were assessed at the delivery. The outcome variables were assessed in terms of miscarriage, SGA, low birthweight, PE and oligohydramnios. The standard definitions used included: miscarriage as fetal loss before 20 weeks of gestation; SGA as birthweight of less than the 10th centile for the gestational age;7 low birthweight as birthweight less than 2500 g;7 PE as the presence of systolic blood pressure ≥ 140 mmHg and/or diastolic blood pressure ≥ 90 mmHg after 20 weeks of pregnancy detected on two or more occasions separated by 6 h with the presence of proteinuria ≥1 + on dipstick or >0.3 g/ 24 h;8 spontaneous preterm delivery as
J. Obstet. Gynaecol. Res. Vol. 41, No. 7: 1003–1008, July 2015
Adverse pregnancy outcome in patients with low pregnancy-associated plasma protein-A: The Indian Experience Sangeeta Gupta1, Manisha Goyal2, Deepti Verma3, Anjana Sharma2, Namita Bharadwaj2, Madhulika Kabra4 and Seema Kapoor2 1
Division of Fetal Medicine, Department of Obstetrics & Gynecology, 3Department of Obstetrics & Gynecology, 2Division of Genetics & Metabolism, Department of Pediatrics, Maulana Azad Medical College, 4Division of Genetics, Department Of Pediatrics, All India Institute Of Medical Sciences, New Delhi, India
Abstract Aim: The aim of our study was to examine the association of low pregnancy-associated plasma protein-A (PAPP-A) with adverse pregnancy outcome. Material and Methods: A total of 1640 consecutive pregnant women between 9+5 and 13+6 weeks of pregnancy were recruited. One hundred and thirty women with PAPP-A levels < 0.4 multiple of median were followed till delivery and the outcome information was obtained for fetal loss, birthweight, growth restriction, preterm birth, reduced liquor and development of pre-eclampsia. Results: During the study period, 130 (7.92%) women had low PAPP-A and were considered as cases and 200 women with normal PAPP-A were controls. Intrauterine growth restriction was observed in 28 (21.54%) cases as compared to 10 (5%) controls. Pre-eclampsia presented in 24 (18.46%) cases and in 18 (9%) controls. Twenty (15.38%) cases had preterm delivery compared to 12 (6%) controls. Fifty-six (43.08%) cases delivered lowbirthweight babies compared to 22 (11%) controls. Thus, the incidence of intrauterine growth restriction, preterm birth and low birthweight was significantly more in the cases as compared to the control group. Conclusions: PAPP-A is a valuable analyte for predicting risk of adverse pregnancy outcome and women with low serum PAPP-A levels would benefit from closer surveillance. Key words: fetal loss, intrauterine growth restriction, pregnancy outcome, pre-eclampsia, preterm birth.
Introduction Maternal serum pregnancy-associated plasma protein-A (PAPP-A) has been widely used in conjunction with free β-human chorionic gonadotrophin (hCG) level and nuchal translucency on ultrasound in firsttrimester screening to calculate the risk for trisomy 21
and other fetal aneuploidies. This robust marker physiologically is highly expressed in the syncytiotrophoblast of the placenta, which is the main source of circulating PAPP-A in pregnancy.1 It is basically akin to insulin-like growth factor binding protein-4 (IGFBP-4), which facilitates the breakdown of this protein resulting in a release of free insulin-like growth factor (IGF).2
Received: July 3 2014. Accepted: November 5 2014. Reprint request to: Dr Seema Kapoor, Division of Genetics & Metabolism, Department of Pediatrics, Maulana Azad Medical College, New Delhi, India. Email: [email protected] S.K. and S.G. conceived the idea of the project, D.V. recruited the patients, N.B. and A.S. applied the tests. M.G. helped in analysis of data and writing the manuscript. M.K. critically reviewed the manuscript. S.K. finally critically reviewed the manuscript and will actas guarantor for the paper.
© 2015 The Authors Journal of Obstetrics and Gynaecology Research © 2015 Japan Society of Obstetrics and Gynecology
1003
S. Gupta et al.
Locally synthesized IGF play an important role in promoting cellular mitosis and differentiation and in the control of trophoblastic invasion of the deciduas.3 Their role in the control of fetal growth is important as they regulate the uptake of amino acids and glucose in the trophoblast.4 Low levels of maternal serum PAPP-A are thought to be representative of decreased levels of PAPP-A at a local level and this translates to low levels of active IGF. Thus, impaired level of free IGF affecting the fetal growth may reflect other adverse pregnancy complications, such as stillbirth, intrauterine growth restriction (IUGR), preeclampsia (PE) and preterm labour.3,5 The predictably early detection of low first-trimester PAPP-A levels might identify women at high risk, help to triage the efforts of obstetricians in a busy outdoor clinic and augment efforts in planning of prenatal care. Thus we propose that in a country where insurance does not pay for a child with intellectual disability, preventive strategies may be the only option of preventing births of children with trisomies. Furthermore, if a serum marker can direct attention to a cohort who require strict surveillance, it would add significant value in its implementation. We present our experience with utility of low PAPP-A as an important marker in a north Indian cohort and discuss its utility in a resource-poor country.
Methods We enrolled all consecutive pregnant women presenting to the antenatal clinic of the Department of Obstetrics and Gynecology between 9+5 and 13+6 weeks of pregnancy. The aim of our study was to determine the association of low PAPP-A levels with adverse pregnancy outcome. The objective of the study was to correlate low PAPP-A with stillbirth, IUGR, PE and preterm labor. The gestational age at the time of blood sampling was calculated by crown–rump length in case a first trimester ultrasound was available and by date of last menstrual period if ultrasound was not available and the cycles were regular. Patient’s exact age, weight, gestation age by last menstrual period, presence of diabetes mellitus, hypertension or cardiovascular disease and history of any child with Down syndrome or any other genetic disease were determined. Smoking status was also determined, even though it is uncommon in India. Upon recruitment, the demographic characteristics were noted. Patients were given an informed consent form and a patient information sheet in the vernacular
1004
language of both Hindi and Urdu about the risk of fetal aneuploidies. The informed consent was directed to her spouse if she was illiterate or failed to conceive the concept of risk. Three to four milliliters of venous sample was collected. Serum was stored in batches of 80 at −20°C till analysis was done and this was always completed within the timeframe of action, which was usually 1.5–2 weeks. Testing was done by timeresolved fluorometry using kits manufactured by M/S Perkin Elmer. Coefficient of variation of less than 5% of the test was taken as acceptable. The markers evaluated in the first trimester were PAPP-A and free β-hCG. Nuchal translucency and crown–rump length were assessed by a single trained sonographer blinded to the results of the biochemical testing. The risk for trisomy 21,18,13 was calculated by in-house Lifecycle software version 3.2 based risk, which was generated for fetal aneuploidies from the pregnant woman’s ‘a priori age risk’ and the likelihood rates of the distribution of biochemical markers and/or nuchal translucency. The report contained both individual values of the analytes and their values modified as multiples of median (MoM). An MoM value of 1 meant that the marker level was equal to the median level for an unaffected pregnancy with the specified gestational age, maternal weight, ethnicity and smoking status while a value of 2 meant that the marker level was twice as high as the median level for an unaffected pregnancy with the specified gestational age, maternal weight, ethnicity and smoking status. All women with PAPP-A levels less than 0.4 MoM of first-trimester biochemical screening were selected as cases and women with similar gestational age and with normal serum PAPP-A levels were taken as control. Values of 0.4 MoM were taken as this value had previously reported with adverse pregnancy outcome.6 The Down syndrome risk was calculated and the cut-off value taken in the first trimester for offering invasive testing was 1:50. Genetic counseling was provided and those with a positive result were offered chorionic villous sampling or amniocentesis depending upon the patient’s choice and the gestational age at which she returned after counseling. Each participant received a study protocol and was instructed to bring it to every appointment during pregnancy, including the stay at the delivery ward. The subjects in the whole study group were followed as per the hospital protocols. Monthly follow-up was done for outdoor clinic patients and daily follow-up was done for admitted patients. Clinical management of the individual pregnancies, including the use of steroids,
© 2015 The Authors Journal of Obstetrics and Gynaecology Research © 2015 Japan Society of Obstetrics and Gynecology
Pregnancy outcome with low PAPP-A
tocolysis, additional ultrasounds or iatrogenic premature delivery, was left to independent attending physicians. Outcome information was obtained by antenatal records of recruited patients for spontaneous fetal loss, termination of pregnancy, small-for-gestational-age (SGA) birth, preterm birth, IUGR, reduced liquor on ultrasonography and development of PE. All the participants detected with major ultrasonic or chromosomal abnormality, women with insulin-dependent diabetes mellitus, chronic hypertension, cardiac disorders, renal disorders, multiple gestation or who had a self-motivated pregnancy termination were excluded. All of these pregnancies were followed till delivery and the results were obtained. The gestational age at delivery, neonatal birthweight, Apgar score, malformations and Ballard’s score were assessed at the delivery. The outcome variables were assessed in terms of miscarriage, SGA, low birthweight, PE and oligohydramnios. The standard definitions used included: miscarriage as fetal loss before 20 weeks of gestation; SGA as birthweight of less than the 10th centile for the gestational age;7 low birthweight as birthweight less than 2500 g;7 PE as the presence of systolic blood pressure ≥ 140 mmHg and/or diastolic blood pressure ≥ 90 mmHg after 20 weeks of pregnancy detected on two or more occasions separated by 6 h with the presence of proteinuria ≥1 + on dipstick or >0.3 g/ 24 h;8 spontaneous preterm delivery as
