- Email: [email protected]
The costs of multiple pregnancy
Inr J Gynecol Ohsrer. 1991, 36: 109-114 International Federation of Gynecology and Obstetrics
109
The costs of multiple pregnancy* L.G. Keith”,
E. Papiernikb
and B. Luke”
‘Department of Obstetrics and Gynecology, Northwestern University Medical School and Prentice Women’s Hospita1 and Maternity Center of The Northwestern Memorial Hospital, Chicago, Illinois (USA), “The University of Paris-South and the Departmenr of Obstetrics and Gynecology. Hospita1 Antoine Beclere. Clamart (F,rance) and <‘Divisionof Maternal-Fetal Medicine, Department of Gynecology and Obstetrics. Johns Hopkins University School of Medicine. Baltimore, Maryland (USA)
(Received May 9th. 1990) (Revised and accepted October 29th, 1990)
Abstract This paper reviews US vita1 statistics to describe the increase in multiple births in the United States between 1977 and 1987 and clarify the participation of differing maternal ethnic and age groups to this trend. The projected needs for NICU beds and costs of handicaps are estimated based on the distribution of low birthweights in multiple gestations. The potential methoak of changing the distribution of low birthweight infants in multiple pregnancies are discussed. Keywords: Multiple pregnancy; Costs.
Obstetricians generally are aware of the high-risk nature of multiple pregnancy. Classic matemal risks include anemia, polyhydramnios, toxemia, preterm delivery (< 37 weeks) and postpartum hemorrhage. Whereas the poor obstetrical outcome of multifetal pregnancy is wel1 known, clinicians often do not consider the magnitude of these ‘Presented in part at the 33rd Pan American Conference on Sterility and Fertility, Casa Del Campo, The Dominican Republic, February 8, 1990. 0020-1292/91/503.50 0 1991 International Federation of Gynecology and Obstetrics Published and Printed in Ireland
outcomes in terms of lives lost or diminished quality of life as a result of handicaps. They also do not consider the costs of these problems [1,2]. One of the live major medical risks associated with multiple pregnancy, namely the increased rate of preterm birth, accounts for the vast majority of problems and their related costs. Unfortunately, simple preventive measures designed to reduce the rate of the most dangerous preterm births often may not be applied because they are considered too costly [l]. Nonetheless, society is obliged to deal with the expenditures required to compensate for preterm delivery; moreover, these costs are borne by al1 of society [2]. In the case of multiple pregnancies, risk of preterm delivery accounts for expenditures vastly out of proportion with the prevalente of the condition. This paper wil1 consider three distinct issues related to multiple gestation. The lïrst is the extent and the nature of the explosive increase in numbers of twins and higher order multiple births. The second is the inevitability of preterm delivery in substantial numbers of mothers of multiples. The third is the growing awareness of the true costs of these events and how these costs impact upon society. Data are drawn from US vita1 statistics and selected intemational publications which address these issues. Clinical and Clinical Research
I 10
Keiih et ai.
The epidemie of multiple births
26 25 -
The practicing clinician generally does not consider national or international statistics as he or she goes about performing daily tasks. Often, data pertaining to rates and trends of specific events are presented in governmental reports that are difficult to interpret. Such is the case with data regarding the incidence and prevalente of multiple gestation. Figure 1 displays the extent of the changes in numbers of multiple births in the United States between 1977 and 1987 based on data from the US vita1 statistics. Between 1977 and 1986, there were 35 180 824 singleton births and 720 400 multiple births in the United States. During this time, the number of twin births rose by about 30%, and this rise was paralleled by a similar increase in the rate of al1 multiple births. The Afro-American and the Caucasian segments of the American population both contributed to the increase in twin and multiple births, as is seen in Fig. 2. The, multiple birth ratio in this figure is the ratio of multiples to al1 births. The causes of the observed changes are not totally clear. It has been widely presumed that they result from the availability of assisted reproductive technologies (ART) or the use of fertility enhancing agents. However, both treatments are expensive and, in al1 probability, not equally available to al1 segments of the
-
1977
1979
1981
, 197?
1978
, ,979
Fig. 2. Multiple 1977- 1987.
(
lssa
birth
,
,
,981
1982
ratio
,
,983
(
,984
(MBR),
,
19%
United
,
ISSS
(
,987
States
population. Moreover, the data of Fig. 2 clearly document that a substantial portion of the increase occurred in the years these treatment modalities for were unavailable prescription except from a smal1 number of highly trained infertility experts. A biologically plausible explanation for the increase in multiple births relates to changing pattems of child bearing (Fig. 3). Between 1977 and 1987, a 30% deciine was observed in multiple births to adolescents and a concomitant and marked rise (47%) was noted among gravidas 35 years of age and older. In contrast, the increase in the incidence of multiple births among women 20-34 years of age during the same years was modest. Because the highest rates of dizygotic twinning normally
Multiple Births Twin Births 1983
1985
Fig. 1. Multiple births, United States 1977-1987. Int J Gynecol Obstet 36
.. .. .. . ..--. .. . .. .. ._.___.,_,rc 18,
1987
Fig. 3. Percent change in incidence of twin births by maternal age since 1977, United States.
The cosîs of multiple pregnancy
occur in adolescents and women over age 35, the changes noted among these two age groups may reflect increased numbers of induced abortions (including multiples) among adolescents and both delayed and increased child bearing among the older group of women. At present, it is not possible to accurately quantitate the proportion of multiple births due to ART or use of fertility agents in the United States. Even the 1989 version of the US Standard Certificate of Birth does not differentiate whether a conception is natura1 or induced [3]. The inevitability of preterm birth among multiple gestations Presently, there are no published US National data comparing multiples and singletons on a weight-for-gestational age basis. However, regardless of point in gestation, a higher proportion of twins are born at low birthweight compared to singletons. This circumstance is reflected in a relative risk of perinatal mortality of at least 4.25 for multiple versus singletons. Unfortunately, this differential mortality rate cannot be further refined to separate twins from higher order multiples. A reflection of what might be expected from national data is obtained from a 1982 publication on more than 2 million births in California between 1970 and 1976 (Fig. 4) [4]. Under the best of circumstances, twins are more than four times likely to die than
singletons. Comparable data for triplets and higher order multiples were not presented in this study, but it can be inferred that the ideal point for triplets would be at a lower gestational age and lesser birthweight, and that the perinatal mortality would increase geometrically. Costs related to preterm delivery The increased rate of preterm delivery accounts for the majority of the costs associated with multiple pregnancy. Only a fraction of al1 multiples account for the greatest concern. These are the very early births, i.e., those between 26 and 31 weeks. The majority of these very premature infants weigh less than 1500 g at birth, and require lengthy stays in the NICU. Recent data quantitating the duration of these hospitalizations have been provided by workers at the Johns Hopkins Hospita1 in Baltimore, Maryland. In this as yet unpublished study, the length of NICU stay among twins doubles for each 500 g increment below birthweights of 2000 g [5]. Among survivors, the risk of moderate to severe handicap is vastly increased as birthweight decreases. The relationship between preterm delivery and tost becomes particularly apparent when the skewed distribution of birthweights among twins toward extremely low categories is considered (Table 1). In al1 probability, the tost calculations presented in this paper give an underestimation of the problem. However, our decision to use reference data from the United Kingdom [6] to estimate costs relates to prior work in this area by Papiemik [l] and
TaMe
1.
Birthweight
distribution/lOOO Singletons
22
30
34
42
III
births. Twins
2
1001-1500
6
40 65
1501-2500
35
425
957
410
44
Completed Weeks Gestation
>2500 Fig. 4.
Lowest perinatal mortality rates by mean birthweight 1970-1976 (N = 2 228 806). and gestational age, Califomia
Adapted
from Simpson and Walker
[6].
Clinical and Clinical Reseurch
112
Keith et al
Table 2.
Singletons Twins Triplets Quads
Rate and relative risk NICU admission and neonatal death/lOOO babies. Expected NICU admissions
Relative risk
Expected no. neonatal deaths
Relative risk
24 172 421 > 520
1.0 7.2 17.5 22.0
4 32 77 104
I 8 19 26
Adapted from Simpson and Walker [6] and Stewart et al. [7].
the ease of understanding a series of interrelated estimations. As can be seen from Table 1, a full 10% of twins are born weighing 1500 g or less compared to 1% in a singleton population. Using the birthweight distribution previously shown, the rate of transfer to NICU11000 births can easily be calculated (Table 2). Not only are twins at elevated risk for NICU admission, but this risk increases dramatically for triplets and quadruplets. The relative risk of neonatal death has a similar distribution. Twins are at greater risk than singletons and this risk expands geometrically for triplets and quadruplets. The need for NICU days vis-a-vis tost per 1000 babies and proportionate tost per pregnancy is shown in Table 3. The relationship between the rising numbers of multiple pregnancies and their unavoidably associated preterm deliveries now becomes clear. Regardless of whether NICU costs are
Table 3.
calculated per 1000 pregnancies or apportioned per pregnancy, the sums are staggering. It is important to recognize that these costs are societal costs, because only rarely are individual parents capable of assuming such obligations. Low birthweight and length of NICU stay are intimately associated with risk of future handicap and the costs attendant to this condition (Table 4). Although these estimations do not subcategorize handicapped survivors by degree of handicap [7], they are illustrative of the point. Comments Potential solutions for the concerns enumerated above include the following: (1) provision of adequate methods to diagnose multiple pregnancy and provide comprehensive prenatal care; (2) provision for nutritional evaluation and support in the pregravid
Need and tost for NICU days per 1000 live births.
Singletons Twins Triplets Quads
Need (daysl
Relative risk
Cost /lOOO’
Prorated cost/infant
36 4168 20015 26300
I 116 556 731
36000 4168000 20015000 26300000
3600 8336 60045 105000
“Calculated at USSlOOO/day. Adapted from Simpson and Walker [6]. Int J Gynecol Obstet 36
The costs of multiple pregnancy
Tabie 4. births.
Singletons Twins Triplets Quads
Risk, relative r&k and tost for handicaps per 1000
Risk
Relative risk
cost/1OOo
2 16 41 51
1.0 8.0 20.5 26.5
2000000 3WO 16OOOOOO 32800 41000000 123000 51000000 204000
Prorated tost/ infant
Adapted from Stewart et al. [7].
and pregnant state; (3) elimination of inappropriate uses of fertility-enhancing agents and ART which lead to iatrogenic multiple gestation; and (4) consideration of selective reduction in some cases of higher order multiple gestation. Early diagnosis is the key to providing optimal antepartum care and the cornerstone of effective management of labor and delivery. Dramatic improvements in perinatal mortality and maternal outcome often result from early diagnosis and the initiation of antenatal care which focuses on the reduction or elimination of risk factors amenable to change. The most important advance in the diagnosis of twin gestation has been the development of clinical ultrasonography. Between 6 and 10 weeks of gestation, vagina1 or abdominal probes can establish the presence of two or more fetuses as wel1 as delineate the presence or absence of membranes between them. Later in pregnancy, ultrasound can assess fetal size, estimate gestational age, determine placenta1 location and quantitate amniotic fluid volume
M. Once the diagnosis of multiple gestation has been made, the importante of prenatal nutrition cannot be sufficiently stressed. Aside from length of gestation, preconceptional weight and gestational weight gain are the two most important factors affecting birthweight. According to Pederson et al. [9], optimal pregnancy outcome, defïned as birth L 37 weeks gestation, both infants 1 2500 g,
113
each with Apgar scores 1 7, was associated with gestational weight gains of 20 kg versus 16.8 kg for women with less than optimal outcome. In a survey of 200 mothers of twins conducted at the 1989 Twinsburg Festival, at Twinsburg, Ohio, researchers from Johns Hopkins Hospita1 and the Center for the Study of Multiple Birth in Chicago found that women who carried to term had pregravid weights averaging 10% higher (110% ideal weight-for-height) and a total gestational weight gain of about 23 kg. This is compared to women delivering preterm whose pregravid weight averaged 100% weight-for-height and who gained only about 18 kg [ 101. Although it is not possible to determine the exact percentage of higher order multiples which result from the injudicious use of fertility-promoting agents or ART, the explosive number of quadruplets, quintuplets and sextuplets in some developed countries suggest that many are iatrogenically produced. For example, prior to the year 1970, the occurrence of higher order multiples in England and Wales was a relatively stable phenomenon. After 1970, despite the number of deliveries declining by almost 40%, the number of quadruplets and quintuplets in[ 111. Similarly, in creased geometrically Germany between 1922 and 1983, there were 92 sets of triplets, whereas between 1984 and 1989 there were 225. There were only 15 sets of quadruplets between 1912 and 1983, but 40 were delivered between 1984 and 1988. NO quintuplets were bom prior to 1972, but 17 sets were counted from 1972 and 1988 [12]. Perhaps the most accurate American estimation of the impact of fertility-inducing agents and ART on the number of multiples comes from a survey prepared by the Triplet Connection of Stockton, Califomia [ 131. Among 1465 responses, 62% (845) of 1355 triplets and 87% (80) of 92 quadruplet gestations, respectively, resulted from ART. In light of the known risk of multiple birth subsequent to the use of ovulation-inducing agents and/or ART, it is incumbent upon physicians using such techniques to provide Clinical and Clinical Research
114
Keith et al.
their patients with relevant information on the basis of which informed decisions can be made. One of the proposed, albeit highly controversial, solutions to higher order multiple gestations is selective reduction. In this procedure, one or more fetuses are sacrifïced in the hopes of avoiding the preterm delivery of several infants with very low birthweight. Such operations are not widely available, and their application usually evoke profound ethica1 as wel1 as medical debates [ 141. Summary The epidemie of multiple pregnancy is of concern because of the need to provide high quality intensive neonatal support to large numbers of low birthweight infants. To the extent possible, the iatrogenic contribution to this problem should be diminished and physicians should implement al1 possible means to prevent preterm delivery in these cases. Acknowledgment Supported by The Center for the Study of Multiple Births and the Celia Porter Charitable Trust, Chicago, Illinois.
Luke B. Keith L: A critical commentary on the U.S. standard at live birth. J Reprod Med 36: 579. 1991. 4 Williams RL, Creasy RK, Cunningham GC. Hawes WE, Norris FD, Tashiro M: Fetal growth and perinatal viability in Califomia. Obstet Gynecol 59: 624. 1982. 5 Feng T, Luke B, Witter F, Namoum A: Perinatal morbidity in newborn twins: Association between birth weight, zygosity and length of hospita1 stay (unpublished data). 6 Simpson H, Walker G: Estimating the costs required for neonatal intensive care. Arch Dis Child 56: 90. 1981. 7 Stewart AL, Reynolds EOR, Lipscomb AP: Outcome for infants of very low birth weight. Survey of world literature. Lancet i: 1038, 1981. 8 Socol M: Multiple gestation. In: Diagnostic Ultrasound Applied to Obstetrics and Gynecology, 2nd edn (ed R.E. Sabbagha), pp 175-179. J.B. Lippincott, Philadelphia. PA, 1987. 9 Pederson AL, Worthington-Roberts B. Hickok DE: Weight gain pattems during twin gestation. J Am Diet Assoc 89: 642, 1989. 10 Luke B, Markowitz R, Keith D, Keith LG, Johnson TRB. Bradford V, Paige DM: The inlluence of matemal pregravid weight, gestational weight gain, and zygosity on birth weight in twin gestations. Poster presented at The VIth International Congress on Twin Studies, Rome. Italy, 1989 (manuscript in preparation). 11 OPCS Birth Statistic Series, FMI United Kingdom, 1989. 12 Grutzner H, Grutzner P, Grutzner B: Hohergradige Mehrlinge in Wandel der Zeit. Geburtshilfe Frauenheilkd 50: 368, 1990. 13 Bleyel J: The triplet connection. Personal Comments, January IS, 1989. 14 Lynch L, Berkowitz RL, Chitkara U, Alvarez M: Fint trimester transabdominal multi fetal pregnancy reduction: a report of 85 cases. Obstet Gynecol 75: 735, 1990. 3
References Addrem for reprinb: 1 2
Papiernik E: Social costs of twin births. Acts Genet Med Gemellol 32: 105, 1983. Tresmontant R, Heluin Cl, Papiernik E: Cost of care and prevention of preterm births in twin pregnancies. Acts Genet Med Gemellol 32: 99, 1983.
Int J Gynecol Obstet 36
L.G. Keith Prentice Wnmen’s Hospltal 333 E. Superior Street, Room 464 Cbieago, IL 60611, USA
109
The costs of multiple pregnancy* L.G. Keith”,
E. Papiernikb
and B. Luke”
‘Department of Obstetrics and Gynecology, Northwestern University Medical School and Prentice Women’s Hospita1 and Maternity Center of The Northwestern Memorial Hospital, Chicago, Illinois (USA), “The University of Paris-South and the Departmenr of Obstetrics and Gynecology. Hospita1 Antoine Beclere. Clamart (F,rance) and <‘Divisionof Maternal-Fetal Medicine, Department of Gynecology and Obstetrics. Johns Hopkins University School of Medicine. Baltimore, Maryland (USA)
(Received May 9th. 1990) (Revised and accepted October 29th, 1990)
Abstract This paper reviews US vita1 statistics to describe the increase in multiple births in the United States between 1977 and 1987 and clarify the participation of differing maternal ethnic and age groups to this trend. The projected needs for NICU beds and costs of handicaps are estimated based on the distribution of low birthweights in multiple gestations. The potential methoak of changing the distribution of low birthweight infants in multiple pregnancies are discussed. Keywords: Multiple pregnancy; Costs.
Obstetricians generally are aware of the high-risk nature of multiple pregnancy. Classic matemal risks include anemia, polyhydramnios, toxemia, preterm delivery (< 37 weeks) and postpartum hemorrhage. Whereas the poor obstetrical outcome of multifetal pregnancy is wel1 known, clinicians often do not consider the magnitude of these ‘Presented in part at the 33rd Pan American Conference on Sterility and Fertility, Casa Del Campo, The Dominican Republic, February 8, 1990. 0020-1292/91/503.50 0 1991 International Federation of Gynecology and Obstetrics Published and Printed in Ireland
outcomes in terms of lives lost or diminished quality of life as a result of handicaps. They also do not consider the costs of these problems [1,2]. One of the live major medical risks associated with multiple pregnancy, namely the increased rate of preterm birth, accounts for the vast majority of problems and their related costs. Unfortunately, simple preventive measures designed to reduce the rate of the most dangerous preterm births often may not be applied because they are considered too costly [l]. Nonetheless, society is obliged to deal with the expenditures required to compensate for preterm delivery; moreover, these costs are borne by al1 of society [2]. In the case of multiple pregnancies, risk of preterm delivery accounts for expenditures vastly out of proportion with the prevalente of the condition. This paper wil1 consider three distinct issues related to multiple gestation. The lïrst is the extent and the nature of the explosive increase in numbers of twins and higher order multiple births. The second is the inevitability of preterm delivery in substantial numbers of mothers of multiples. The third is the growing awareness of the true costs of these events and how these costs impact upon society. Data are drawn from US vita1 statistics and selected intemational publications which address these issues. Clinical and Clinical Research
I 10
Keiih et ai.
The epidemie of multiple births
26 25 -
The practicing clinician generally does not consider national or international statistics as he or she goes about performing daily tasks. Often, data pertaining to rates and trends of specific events are presented in governmental reports that are difficult to interpret. Such is the case with data regarding the incidence and prevalente of multiple gestation. Figure 1 displays the extent of the changes in numbers of multiple births in the United States between 1977 and 1987 based on data from the US vita1 statistics. Between 1977 and 1986, there were 35 180 824 singleton births and 720 400 multiple births in the United States. During this time, the number of twin births rose by about 30%, and this rise was paralleled by a similar increase in the rate of al1 multiple births. The Afro-American and the Caucasian segments of the American population both contributed to the increase in twin and multiple births, as is seen in Fig. 2. The, multiple birth ratio in this figure is the ratio of multiples to al1 births. The causes of the observed changes are not totally clear. It has been widely presumed that they result from the availability of assisted reproductive technologies (ART) or the use of fertility enhancing agents. However, both treatments are expensive and, in al1 probability, not equally available to al1 segments of the
-
1977
1979
1981
, 197?
1978
, ,979
Fig. 2. Multiple 1977- 1987.
(
lssa
birth
,
,
,981
1982
ratio
,
,983
(
,984
(MBR),
,
19%
United
,
ISSS
(
,987
States
population. Moreover, the data of Fig. 2 clearly document that a substantial portion of the increase occurred in the years these treatment modalities for were unavailable prescription except from a smal1 number of highly trained infertility experts. A biologically plausible explanation for the increase in multiple births relates to changing pattems of child bearing (Fig. 3). Between 1977 and 1987, a 30% deciine was observed in multiple births to adolescents and a concomitant and marked rise (47%) was noted among gravidas 35 years of age and older. In contrast, the increase in the incidence of multiple births among women 20-34 years of age during the same years was modest. Because the highest rates of dizygotic twinning normally
Multiple Births Twin Births 1983
1985
Fig. 1. Multiple births, United States 1977-1987. Int J Gynecol Obstet 36
.. .. .. . ..--. .. . .. .. ._.___.,_,rc 18,
1987
Fig. 3. Percent change in incidence of twin births by maternal age since 1977, United States.
The cosîs of multiple pregnancy
occur in adolescents and women over age 35, the changes noted among these two age groups may reflect increased numbers of induced abortions (including multiples) among adolescents and both delayed and increased child bearing among the older group of women. At present, it is not possible to accurately quantitate the proportion of multiple births due to ART or use of fertility agents in the United States. Even the 1989 version of the US Standard Certificate of Birth does not differentiate whether a conception is natura1 or induced [3]. The inevitability of preterm birth among multiple gestations Presently, there are no published US National data comparing multiples and singletons on a weight-for-gestational age basis. However, regardless of point in gestation, a higher proportion of twins are born at low birthweight compared to singletons. This circumstance is reflected in a relative risk of perinatal mortality of at least 4.25 for multiple versus singletons. Unfortunately, this differential mortality rate cannot be further refined to separate twins from higher order multiples. A reflection of what might be expected from national data is obtained from a 1982 publication on more than 2 million births in California between 1970 and 1976 (Fig. 4) [4]. Under the best of circumstances, twins are more than four times likely to die than
singletons. Comparable data for triplets and higher order multiples were not presented in this study, but it can be inferred that the ideal point for triplets would be at a lower gestational age and lesser birthweight, and that the perinatal mortality would increase geometrically. Costs related to preterm delivery The increased rate of preterm delivery accounts for the majority of the costs associated with multiple pregnancy. Only a fraction of al1 multiples account for the greatest concern. These are the very early births, i.e., those between 26 and 31 weeks. The majority of these very premature infants weigh less than 1500 g at birth, and require lengthy stays in the NICU. Recent data quantitating the duration of these hospitalizations have been provided by workers at the Johns Hopkins Hospita1 in Baltimore, Maryland. In this as yet unpublished study, the length of NICU stay among twins doubles for each 500 g increment below birthweights of 2000 g [5]. Among survivors, the risk of moderate to severe handicap is vastly increased as birthweight decreases. The relationship between preterm delivery and tost becomes particularly apparent when the skewed distribution of birthweights among twins toward extremely low categories is considered (Table 1). In al1 probability, the tost calculations presented in this paper give an underestimation of the problem. However, our decision to use reference data from the United Kingdom [6] to estimate costs relates to prior work in this area by Papiemik [l] and
TaMe
1.
Birthweight
distribution/lOOO Singletons
22
30
34
42
III
births. Twins
2
1001-1500
6
40 65
1501-2500
35
425
957
410
44
Completed Weeks Gestation
>2500 Fig. 4.
Lowest perinatal mortality rates by mean birthweight 1970-1976 (N = 2 228 806). and gestational age, Califomia
Adapted
from Simpson and Walker
[6].
Clinical and Clinical Reseurch
112
Keith et al
Table 2.
Singletons Twins Triplets Quads
Rate and relative risk NICU admission and neonatal death/lOOO babies. Expected NICU admissions
Relative risk
Expected no. neonatal deaths
Relative risk
24 172 421 > 520
1.0 7.2 17.5 22.0
4 32 77 104
I 8 19 26
Adapted from Simpson and Walker [6] and Stewart et al. [7].
the ease of understanding a series of interrelated estimations. As can be seen from Table 1, a full 10% of twins are born weighing 1500 g or less compared to 1% in a singleton population. Using the birthweight distribution previously shown, the rate of transfer to NICU11000 births can easily be calculated (Table 2). Not only are twins at elevated risk for NICU admission, but this risk increases dramatically for triplets and quadruplets. The relative risk of neonatal death has a similar distribution. Twins are at greater risk than singletons and this risk expands geometrically for triplets and quadruplets. The need for NICU days vis-a-vis tost per 1000 babies and proportionate tost per pregnancy is shown in Table 3. The relationship between the rising numbers of multiple pregnancies and their unavoidably associated preterm deliveries now becomes clear. Regardless of whether NICU costs are
Table 3.
calculated per 1000 pregnancies or apportioned per pregnancy, the sums are staggering. It is important to recognize that these costs are societal costs, because only rarely are individual parents capable of assuming such obligations. Low birthweight and length of NICU stay are intimately associated with risk of future handicap and the costs attendant to this condition (Table 4). Although these estimations do not subcategorize handicapped survivors by degree of handicap [7], they are illustrative of the point. Comments Potential solutions for the concerns enumerated above include the following: (1) provision of adequate methods to diagnose multiple pregnancy and provide comprehensive prenatal care; (2) provision for nutritional evaluation and support in the pregravid
Need and tost for NICU days per 1000 live births.
Singletons Twins Triplets Quads
Need (daysl
Relative risk
Cost /lOOO’
Prorated cost/infant
36 4168 20015 26300
I 116 556 731
36000 4168000 20015000 26300000
3600 8336 60045 105000
“Calculated at USSlOOO/day. Adapted from Simpson and Walker [6]. Int J Gynecol Obstet 36
The costs of multiple pregnancy
Tabie 4. births.
Singletons Twins Triplets Quads
Risk, relative r&k and tost for handicaps per 1000
Risk
Relative risk
cost/1OOo
2 16 41 51
1.0 8.0 20.5 26.5
2000000 3WO 16OOOOOO 32800 41000000 123000 51000000 204000
Prorated tost/ infant
Adapted from Stewart et al. [7].
and pregnant state; (3) elimination of inappropriate uses of fertility-enhancing agents and ART which lead to iatrogenic multiple gestation; and (4) consideration of selective reduction in some cases of higher order multiple gestation. Early diagnosis is the key to providing optimal antepartum care and the cornerstone of effective management of labor and delivery. Dramatic improvements in perinatal mortality and maternal outcome often result from early diagnosis and the initiation of antenatal care which focuses on the reduction or elimination of risk factors amenable to change. The most important advance in the diagnosis of twin gestation has been the development of clinical ultrasonography. Between 6 and 10 weeks of gestation, vagina1 or abdominal probes can establish the presence of two or more fetuses as wel1 as delineate the presence or absence of membranes between them. Later in pregnancy, ultrasound can assess fetal size, estimate gestational age, determine placenta1 location and quantitate amniotic fluid volume
M. Once the diagnosis of multiple gestation has been made, the importante of prenatal nutrition cannot be sufficiently stressed. Aside from length of gestation, preconceptional weight and gestational weight gain are the two most important factors affecting birthweight. According to Pederson et al. [9], optimal pregnancy outcome, defïned as birth L 37 weeks gestation, both infants 1 2500 g,
113
each with Apgar scores 1 7, was associated with gestational weight gains of 20 kg versus 16.8 kg for women with less than optimal outcome. In a survey of 200 mothers of twins conducted at the 1989 Twinsburg Festival, at Twinsburg, Ohio, researchers from Johns Hopkins Hospita1 and the Center for the Study of Multiple Birth in Chicago found that women who carried to term had pregravid weights averaging 10% higher (110% ideal weight-for-height) and a total gestational weight gain of about 23 kg. This is compared to women delivering preterm whose pregravid weight averaged 100% weight-for-height and who gained only about 18 kg [ 101. Although it is not possible to determine the exact percentage of higher order multiples which result from the injudicious use of fertility-promoting agents or ART, the explosive number of quadruplets, quintuplets and sextuplets in some developed countries suggest that many are iatrogenically produced. For example, prior to the year 1970, the occurrence of higher order multiples in England and Wales was a relatively stable phenomenon. After 1970, despite the number of deliveries declining by almost 40%, the number of quadruplets and quintuplets in[ 111. Similarly, in creased geometrically Germany between 1922 and 1983, there were 92 sets of triplets, whereas between 1984 and 1989 there were 225. There were only 15 sets of quadruplets between 1912 and 1983, but 40 were delivered between 1984 and 1988. NO quintuplets were bom prior to 1972, but 17 sets were counted from 1972 and 1988 [12]. Perhaps the most accurate American estimation of the impact of fertility-inducing agents and ART on the number of multiples comes from a survey prepared by the Triplet Connection of Stockton, Califomia [ 131. Among 1465 responses, 62% (845) of 1355 triplets and 87% (80) of 92 quadruplet gestations, respectively, resulted from ART. In light of the known risk of multiple birth subsequent to the use of ovulation-inducing agents and/or ART, it is incumbent upon physicians using such techniques to provide Clinical and Clinical Research
114
Keith et al.
their patients with relevant information on the basis of which informed decisions can be made. One of the proposed, albeit highly controversial, solutions to higher order multiple gestations is selective reduction. In this procedure, one or more fetuses are sacrifïced in the hopes of avoiding the preterm delivery of several infants with very low birthweight. Such operations are not widely available, and their application usually evoke profound ethica1 as wel1 as medical debates [ 141. Summary The epidemie of multiple pregnancy is of concern because of the need to provide high quality intensive neonatal support to large numbers of low birthweight infants. To the extent possible, the iatrogenic contribution to this problem should be diminished and physicians should implement al1 possible means to prevent preterm delivery in these cases. Acknowledgment Supported by The Center for the Study of Multiple Births and the Celia Porter Charitable Trust, Chicago, Illinois.
Luke B. Keith L: A critical commentary on the U.S. standard at live birth. J Reprod Med 36: 579. 1991. 4 Williams RL, Creasy RK, Cunningham GC. Hawes WE, Norris FD, Tashiro M: Fetal growth and perinatal viability in Califomia. Obstet Gynecol 59: 624. 1982. 5 Feng T, Luke B, Witter F, Namoum A: Perinatal morbidity in newborn twins: Association between birth weight, zygosity and length of hospita1 stay (unpublished data). 6 Simpson H, Walker G: Estimating the costs required for neonatal intensive care. Arch Dis Child 56: 90. 1981. 7 Stewart AL, Reynolds EOR, Lipscomb AP: Outcome for infants of very low birth weight. Survey of world literature. Lancet i: 1038, 1981. 8 Socol M: Multiple gestation. In: Diagnostic Ultrasound Applied to Obstetrics and Gynecology, 2nd edn (ed R.E. Sabbagha), pp 175-179. J.B. Lippincott, Philadelphia. PA, 1987. 9 Pederson AL, Worthington-Roberts B. Hickok DE: Weight gain pattems during twin gestation. J Am Diet Assoc 89: 642, 1989. 10 Luke B, Markowitz R, Keith D, Keith LG, Johnson TRB. Bradford V, Paige DM: The inlluence of matemal pregravid weight, gestational weight gain, and zygosity on birth weight in twin gestations. Poster presented at The VIth International Congress on Twin Studies, Rome. Italy, 1989 (manuscript in preparation). 11 OPCS Birth Statistic Series, FMI United Kingdom, 1989. 12 Grutzner H, Grutzner P, Grutzner B: Hohergradige Mehrlinge in Wandel der Zeit. Geburtshilfe Frauenheilkd 50: 368, 1990. 13 Bleyel J: The triplet connection. Personal Comments, January IS, 1989. 14 Lynch L, Berkowitz RL, Chitkara U, Alvarez M: Fint trimester transabdominal multi fetal pregnancy reduction: a report of 85 cases. Obstet Gynecol 75: 735, 1990. 3
References Addrem for reprinb: 1 2
Papiernik E: Social costs of twin births. Acts Genet Med Gemellol 32: 105, 1983. Tresmontant R, Heluin Cl, Papiernik E: Cost of care and prevention of preterm births in twin pregnancies. Acts Genet Med Gemellol 32: 99, 1983.
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L.G. Keith Prentice Wnmen’s Hospltal 333 E. Superior Street, Room 464 Cbieago, IL 60611, USA