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Multiples clinic: a model for antenatal care
Seminars in Fetal & Neonatal Medicine 15 (2010) 357e361
Contents lists available at ScienceDirect
Seminars in Fetal & Neonatal Medicine journal homepage: www.elsevier.com/locate/siny
Multiples clinic: a model for antenatal care Ellen Knox, William Martin* Birmingham Women’s Hospital, Metchley Park Road, Edgbaston B15 2TG, UK
s u m m a r y Keywords: Antenatal clinic Multiple pregnancy Twins
Antenatal care has become more focused in recent years with an increase in the number of specialist clinics providing care in a multidisciplinary manner. Multiple pregnancies are complex with complications for the mother and babies arising frequently. As a group they lend themselves well to a specialist clinic model where interested doctors and midwives can provide care tailored to the individual. This makes it less likely that complications will be missed and provides a consistent approach to care that patients desire. This article aims to describe models of care that can be given in such a clinic, acknowledging that one model will not fit all. The scant evidence that exists is presented along with selected examples of individual complications. Ó 2010 Elsevier Ltd. All rights reserved.
1. Introduction In recent years there has been a vogue for subspecialism and a multidisciplinary approach to antenatal care. This allows concentration of expertise in one place to provide the patient with optimal care. This care is provided (where relevant) by specialists other than obstetricians, an interested obstetrician supported by (specialist) midwives and with access to additional staff such as anaesthetists, sonographers, day assessment care, etc. There is a paucity of data to show that such specialist care provides improved outcomes but it is logical to assume that care provided by a team of doctors and midwives with an interest in a particular area is likely to be of better quality as it is impossible to be knowledgeable about all aspects of obstetric care. Twins pregnancies make up around 1% of pregnancies and the incidence appears to be increasing. In the UK in 1988, twins comprised 11.1 per 1000 maternities. In 2007 they represented 15.3 per 1000 maternities, with triplets and higher order multiples increasing almost three-fold.1 Dizygous pregnancy rates vary with maternal age, race, nutrition and geography with highest rates in Nigeria and the lowest in Japan. Monozygous twinning rates are fairly constant, at 3e5 per 1000 births, although there have been some anecdotal reports that the incidence is also increasing. These increases are largely due to assisted conception techniques, which result in multiple rates of up to 30%.2 Though predominantly dizygotic, pregnancies which result from assisted conception techniques are at greater risk of monozygotic division than those spontaneously conceived. Both the British Fertility Society and the * Corresponding author. Tel.: þ44 (0)121 6074708; fax: þ44 (0)121 6272667. . E-mail address: [email protected] (W. Martin). 1744-165X/$ e see front matter Ó 2010 Elsevier Ltd. All rights reserved. doi:10.1016/j.siny.2010.07.001
Human Fertilisation and Embryology Authority suggest transferring a maximum of two embryos in each treatment cycle, without compromising pregnancy success. Multiple pregnancies are high risk both for the mother and fetuses. From the maternal point of view there is an increased risk of most pregnancy complications, including miscarriage, hyperemesis gravidarum, premature labour and delivery, anaemia, pre-eclampsia, gestational diabetes, antepartum and postpartum haemorrhage, polyhydramnios, operative delivery and increased stay in hospital, to name but a few. Women who have twins are also at increased risk of having problems with breastfeeding and developing postnatal depression.3 For the fetus and neonate, multiple pregnancies are associated with an increase in mortality compared with singleton pregnancies and this risk increases with increasing order of multiple pregnancy. Perinatal mortality rates are 27.2 and 81.8 per 1000 total births for twins, triplets and higher order multiple births respectively.4 The majority of perinatal deaths are associated with preterm birth and intrauterine growth restriction.4 Monochorionic (MC) twins have an increased loss rate (14.2%) compared with dichorionic (DC) twins (2.6%), mainly due to losses before 24 weeks. The differential loss rate is mainly the result of twinetwin transfusion syndrome (TTTS).5 Antenatal care focused in the correct way can help to ameliorate these risks by identifying the highest risk cases, and with appropriate monitoring and timing of delivery may help to improve outcomes. 2. Evidence for specialist clinics A literature review reveals that there has been little meaningful research carried out in the area of multiple pregnancy and antenatal specialist clinics. A 2009 Cochrane review concluded:
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There is no information available from randomised controlled trials to support the role of ‘specialised’ antenatal clinics for women with a multiple pregnancy compared with ‘standard’ antenatal care in improving maternal and infant health outcomes. The value of ‘specialised’ multiple pregnancy clinics in improving health outcomes for women and their infants requires evaluation in appropriately powered and designed randomised controlled trials.6 There are a few reports suggesting that management protocols may be of benefit.7,8 It seems plausible that dedicated antenatal clinics are beneficial. Women with twins and higher multiple pregnancy are at increased risk of complications. Thus frequent visits with staff tuned in to those risks are likely to lead to identification of such complications earlier. The Royal College of Obstetricians and Gynaecologists (RCOG) Green Top guidelines on monochorionic (MC) twin pregnancy suggest that care for these pregnancies may be best delivered in a dedicated clinic.5 Consistency of information including the use of specific multiple pregnancy guidelines and protocols is more likely. This will provide clarity for both staff and patients. Training is enhanced with the specialist clinic allowing more time for teaching of doctors, midwives and medical students. Centralisation of care aids in participation in multicentre trials and local audit, and allows development of databases to provide accurate unit data on outcome, further enhancing counselling for these complex pregnancies. Finally and perhaps of most importance, patients appreciate the specialist nature of the clinic. It tends not to be overcrowded and thus is less likely to be delayed, a frequent complaint about hospital antenatal clinics. Doctors and midwives have more time to spend discussing all aspects of antenatal and intrapartum care, thus they also prefer these clinics. All the patients attending are in the same boat, often making relationships that last until the birth of their twins and beyond. 3. General issues It is likely that a specialist antenatal multiple clinic will not be practical for all units. However, in a larger unit it is potentially more useful. At the Birmingham Women’s Hospital we deliver more than 7000 babies per annum; this number includes around 140 twins and 3e6 higher multiples. This number lends itself well to a specific multiples clinic model. A specialist multiples clinic provides consistency in antenatal care provided by clinicians experienced in the management of multiple pregnancies. They should be familiar with the importance of monitoring, allowing delivery at the appropriate time in a given circumstance. The lead clinician should ideally be experienced in scanning to give a better appreciation of the subtleties of fetal growth assessment. In difficult cases such a clinician can assess problem pregnancies themselves if there is any cause for concern. 4. Antenatal clinic models Traditionally management of multiple pregnancy is within an antenatal clinic setting. It relies upon scans being performed in the radiology department followed by review in the antenatal clinic. If there are complications then referral is made to a fetal medicine centre. However, an alternative model would be for uncomplicated DC twin pregnancies to be reviewed within a general antenatal clinic and the MC or complicated DC pregnancies being scanned and managed by the multiples lead and specialist midwife sonographers/ radiographers. This could be done through the day assessment unit. This would allow for greater ‘hands on’ input for the more complicated pregnancies. However, the uncomplicated twin pregnancies would not experience the (admittedly unproven) potential benefits
of attending a multiples clinic. The guidance for their care and for referral back to the multiples service if required would also have to be consistently implemented through protocols and/or care pathways. 5. Clinic visit schedule The first point of contact will be at the first visit. The diagnosis may already be known to the couple or potentially have been discovered moments before. A considerable amount of information will be imparted at this visit; much of it will not be retained, and therefore written information, preferably pertaining to the booking hospital figures and outcomes, should be provided when available. Issues requiring discussion include: Any relevant pre-existing conditions that are identified during routine questioning from the booking history. Frequency of attendance: in our clinic MC twins every 2 weeks from diagnosis to identify TTTS early; for DC twins attendance is every 4 weeks from 20 weeks. Risks of the pregnancy to include general advice about hyperemesis gravidarum, anaemia, pregnancy-induced hypertension and its detection, fetal growth problems and how they may be managed with increased frequency of visits and through care in a day assessment unit where possible; and the preterm labour risk. Prenatal diagnosis of Down’s syndrome screening. At Birmingham Women’s Hospital we offer nuchal translucency screening for all patients booking with multiple pregnancy, as it is a more reliable method than the triple test. It is important that the couple are adequately counselled regarding the implications of a disparity in results between the fetuses. They need to be aware of the risks of invasive testing and the possibility of fetal reduction in the event of an anomaly being identified. Ideally this should be discussed a few days prior to the test to allow the couple a chance to consider their position. (The National Screening Committee have produced a patient advice booklet pertaining to these issues e see below.) It is equally important, particularly when a couple have declined trisomy 21 screening to discuss the 20 week scan, to ensure the couple is aware that this is a screening test also. In MC pregnancies, the couple needs to be advised that there is a risk of TTTS of around 15%, and that this can best be identified by frequent scanning throughout pregnancy. (It is helpful to couch this in more positive terms, i.e. that there is an 85% chance that TTTS will not occur). The timings of subsequent clinic visits are determined largely by chorionicity with DC twin pregnancies requiring scanning every 4 weeks from 20 weeks of gestation. If there is any suggestion of suboptimal growth or growth discordance, growth scans should be performed every two weeks, with additional assessment occurring more frequently, for example where there is reduced liquor or abnormal umbilical artery Doppler. If Doppler velocimetry of the umbilical artery is normal, the liquor volume is normal and movements are subjectively satisfactory, then outpatient management in the setting of a day assessment unit or similar can be considered. Abnormal Doppler findings will necessitate more intensive surveillance. These issues are discussed in detail elsewhere in this issue of Seminars. Monochorionic twins require scanning every 2 weeks from diagnosis to delivery,5 to allow the earliest possible diagnosis of TTTS, which if untreated has high mortality for both twins. In MC twins not complicated by TTTS the presence of severe growth discordance may lead to compromise and demise of one twin which carries a risk of severe morbidity and mortality for the surviving twin. Growth discordance is best managed under the
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supervision of the multiples lead, through a fetal assessment/day assessment unit with appropriate fetal medicine review if required. Suspected development of TTTS should trigger referral to a tertiary referral fetal medicine unit with the capability to provide laser treatment if the diagnosis is confirmed.5 6. Delivery Timing of delivery and mode of delivery should be discussed early, and reviewed regularly throughout the pregnancy. At Birmingham Women’s Hospital we prefer to deliver by 38 weeks in uncomplicated MC twins and DC twins where the first twin is cephalic and the couple wish to try. If couples are keen on caesarean section, the pros and cons are discussed including risks for subsequent pregnancies. If they still wish this mode of delivery then we arrange elective delivery between 37þ0 and 38þ0 weeks. The final decisions are made nearer to term to ensure that fetal lie is known and to allow the couple a chance to consider the options. 7. Conditions peculiar to multiple pregnancy A full discussion of such conditions is provided elsewhere in this issue, but some general issues are mentioned here for completeness. It is essential that good links and referral pathways to fetal medicine subspecialists are in place. Where there is discordancy in fetal abnormality, or chromosomal anomaly; where TTTS develops or is suspected; or in higher order pregnancies where selective reduction may be considered, it is important to be able to refer promptly for further counselling and treatment. It is ideal if the lead for multiple pregnancy is subspecialty-trained in fetal medicine and can carry out some or all of the procedures that may be required. This means that they will be able to counsel appropriately, providing the patient with a good understanding of the condition prior to the visit to the fetal medicine department. Single fetal demise is distressing at whatever point it happens in the pregnancy. This eventuality should be considered by the unit and protocols arranged so that in the event of such an occurrence, the sonographer is aware how to proceed. All units should have a quiet room away from antenatal clinic where the couple can be seated. If alone, there should be someone who can sit with the patient until a partner or friend can attend for support. The patient should be seen promptly by an experienced clinician to discuss the likely causes and how the pregnancy is likely to be managed from that point. Follow-up may be more appropriate in another clinic, but some couples wish to continue in the multiples clinic as an acknowledgement that they had previously been pregnant with twins. This desire should be respected, where possible, but in this circumstance the single demise must be clearly and carefully documented to avoid other staff making the understandable error of assuming the pregnancy is ongoing. It is equally important to warn the couple that if they continue in the specialist clinic that such an occurrence may happen. The couple should be offered the chance to see the bereavement team, who in turn should be made aware of the couple’s situation. If the fetal demise is after 24 weeks then at some point, but not on the day of diagnosis unless specifically asked, the couple must be made aware that the baby will require to be registered when born. The implications of demise in an MC twin pregnancy need to be broached and follow-up scans arranged, perhaps with magnetic resonance imaging some 6 weeks later to assess intracranial anatomy. Some more unusual complications require individualised care. For example, monoamniotic twins are likely to need ultrasound scans every 2 weeks from booking to delivery. In view of the risk of cord entanglement, delivery should be at 34 weeks, at the latest, by caesarean section (with prophylactic steroids at 32e33 weeks).
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Higher multiple pregnancies are uncommon. These require individual plans for management. For example, triplets involving a MC twin pair (triamniotic, DC) may develop TTTS. They should therefore have the same clinic/scan scheduling as MC twins. Triplets with separate placentas (triamniotic, trichorionic) are still at risk of growth discordance but not TTTS. In view of the former risk they would still require more frequent clinic attendance. 8. Scan charts for multiple pregnancies Although individual birth weight charts are available for use in singleton pregnancies, charts for twins are population-based. Validated birth weight centiles and estimated fetal weight charts customised for the physiological variables that affect birth weight are not available. Thus currently there is no alternative but to use scan-based biometry charts to assess abdominal circumference, femur length and head circumference to monitor fetal growth in multiple pregnancies. Asymmetrical growth (relatively small abdominal circumference in relation to head circumference and femur length) may suggest placental insufficiency. Symmetrical growth restriction is more likely to suggest either a constitutionally small fetus or an underlying chromosomal or viral cause (especially if the poor growth is of early onset). 9. Staff 9.1. Role of the specialist midwife The specialist midwife plays an important role in the multiples clinic. The need for regular scan review often means that women are seen infrequently by their own community midwife. The specialist midwife therefore provides invaluable midwifery support throughout their pregnancy. The social and financial pressures on patients who are pregnant with multiple pregnancies are often greater than those with a singleton. The midwife working with the lead obstetrician can help to highlight social concerns and refer on to the appropriate support agencies early in pregnancy to provide the necessary help that the woman and her family may need both antenatally and postnatally. They may also provide links to any local specific multiple birth support groups. Following medical consultation regarding the relative merits of vaginal birth versus caesarean section, the specialist midwife can provide additional support and the opportunity to discuss the process further which can help aid the decision-making process. They are also ideally suited to leading parentcraft lessons for this group of women and their partners. In this group the labour, delivery and subsequent postnatal period is often particularly daunting and requires specialist knowledgeable and reassuring support. The specialist midwife can have a role in the education of midwifery colleagues regarding all aspects of multiple pregnancy care, antenatal, intrapartum and postnatal. Although it will not be possible for one midwife to be present at the delivery of all twins, they can through education and support go a long way to ensuring that consistent care is provided to the patients. This applies not only to intrapartum care but also to the important postnatal period when women with twins require additional support with breastfeeding. 9.2. Role of the obstetrician The lead obstetrician is responsible for establishing guidelines for the antenatal and intrapartum management of multiple pregnancy. (S)he should determine a plan of care for each pregnancy at booking after careful review of previous medical and obstetric history and current pregnancy circumstances. (S)he should then be available to review that plan as the pregnancy progresses and
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provide advice to the junior medical staff assisting in clinic. The twins clinic provides an excellent opportunity for teaching because of a relatively small cohort of patients who present frequently, thereby offering continuity of care. It also provides exposure to many obstetric complications, most of which are found more frequently in multiple pregnancies, and the opportunity to learn from a senior clinician with a specific interest. As mentioned earlier, the lead obstetrician should have expertise in the antenatal and intrapatum management of multiple pregnancies. Ideally they should have training in fetal medicine, so that in the event of a complication arising they are able to scan themselves or be able to interpret scans carried out to ensure care is appropriate, prolonging the pregnancy to an optimal gestation and delivering at the correct juncture. If they do not have the practical scan skills themselves they should have a good understanding of the complications of fetal growth discordance in multiple pregnancy and rapid access to those who are able to scan and aid management and delivery decisions. 10. Governance The multiples clinic provides an ideal opportunity for the collection of data regarding pregnancy outcomes. The data obtained can be used in the counselling of patients, allowing them to make informed choices regarding their delivery options. For example, the risk of emergency caesarean after spontaneous or induced labour; or for the second twin following vaginal birth of the first twin. The data collected can be used in audit to help ensure that women are receiving the highest quality care. The importance of good quality care in multiple pregnancy has been recognised in the most recent Clinical Negligence Scheme for Trusts (CNST) National Health Service Litigation Authority (NHSLA) criteria. All trusts will need to have a multiple pregnancy guideline which includes, as a minimum, offering a dating scan and nuchal translucency screening for Down syndrome; a regimen for scan frequency and assessment; discussion regarding mode, timing and place of delivery; referral criteria for suspected TTTS and management of the second stage of labour. A new standard (3.4) for multiple pregnancies requires a case note review to ensure compliance with the guidelines. It is currently a pilot standard but is likely to be adopted as a full standard in the near future. The introduction of specialist clinics should improve care. This may be demonstrated through audit of outcome but the less measurable aspect of patient satisfaction can be assessed through surveys administered through the clinic to ensure care is optimal. It would be impossible (and for training purposes undesirable) for the multiple pregnancy lead to be present at all deliveries. However, through practical training (perhaps with scenario-based drills) they can help to familiarise staff with the practicalities of management in multiple pregnancies. 11. Research The presence of a dedicated multiples clinic provides an ideal opportunity to participate in research programmes. This may relate to conditions and outcomes specific to multiple pregnancy or more general obstetric research. In the realm of conditions specific to multiple pregnancy, one of the most frequently studied complications is prematurity, specifically interventions aiming to reduce premature delivery. The STOPPIT (Study for the prevention of preterm birth in twins) trial9 was a randomised controlled trial (RCT) of vaginal progesterone versus placebo, given to women with twin pregnancy with the aim of preventing preterm birth. There was no reduction in the rate of prematurity in the progesterone arm of the study. Therefore vaginal progesterone should not be given in twin pregnancy for preterm delivery prevention.
A Cochrane review of six studies addressing bed-rest for multiple pregnancy compared to outpatient monitoring concluded that bed rest did not reduce the risk of preterm birth or perinatal mortality.10 In fact significantly more women delivered preterm in the inpatient group of uncomplicated twin pregnancies. For triplet pregnancies there was a suggestion of benefit to inpatient care although the confidence limits around the effect size were large and could therefore have been due to chance variation. With regard to mode of delivery, a Cochrane review found insufficient evidence to support routine caesarean delivery for non-cephalic second twin.11 However, there is evidence that the second twin has higher risk of death and/or serious perinatal morbidity compared to the first twin if delivered vaginally but not if delivered by caesarean section.12 This question is being addressed by the Twin Births Study, an international RCT comparing vaginal delivery with caesarean section for twins at 32e38 weeks (with an estimated weight of 1500e4000 g) where the first twin is presenting vertex and the second twin is nonvertex. Monoamniotic twin pregnancies, lethal congenital malformations of either twin or contraindications to vaginal birth are exclusions to entry in the trial. We await the results of this study to help provide important information with which to counsel regarding mode of delivery. In lieu of such evidence, counselling regarding delivery should involve in-depth discussion about the possible risks and complications of either delivery mode, including risks to future pregnancies, and written information should be supplied. 12. Summary There is a paucity of meaningful research into the use of dedicated multiple pregnancy clinics with a recent Cochrane review concluding that there was no information from RCTs supporting the role of such a clinic. However, it seems plausible that dedicated antenatal clinics are likely to be of benefit providing consistency in care, and likely earlier identification of problems. The role of dedicated clinics is supported by the RCOG for MC twins at least, as a good practice point.5 Dedicated multiple pregnancy clinics have much to recommend them. They may not be helpful in all hospitals but centralisation of expertise when practical seems logical. Ongoing research is helping to guide management. Guidelines and protocols can ensure that consistent advice is given to patients. Complications are more likely to be identified sooner. Appropriate referral pathways should ensure that the various complications seen in multiple pregnancies are treated in the optimal way.
Clinical practice points Multiple pregnancy is well-suited to a specialist clinic model. The majority of multiple pregnancies are uncomplicated but counselling at the booking visit should discuss the commoner conditions that may occur. Screening for Down syndrome is best provided by first trimester nuchal translucency scanning. A scanning schedule should be 4-weekly from 24 weeks for DC twins and 2-weekly from diagnosis for MC twins. MC twins should be referred to tertiary fetal medicine centres where there is suspicion that TTTS is developing. Delivery should be by 38 weeks in DC twins, but there is controversy regarding MC twins with advice varying from elective caesarean section at 34 weeks to vaginal delivery at 38 weeks. Mode of delivery should be discussed and the patient’s wishes respected where safe. If elective caesarean section is contemplated there should be a full discussion including risks in subsequent pregnancy backed up by written information.
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References Research directions The lack of objective data showing that specialist clinics are beneficial suggests one avenue of research. Research in the optimal mode and gestation of delivery. Methods of prediction and prevention of preterm labour.
Appendix. Websites and relevant literature Twins and Multiple Births Association (TAMBA) http://www.tamba.org.uk/Page.aspx?pid¼195 (fee for joining) Multiple Birth Foundation (MBF) http://www.multiplebirths.org.uk/ (fee for obtaining literature produced) National Screening Committe, Down syndrome screening for multiple pregnancy, CNST standard 3.4: www.nhsla.com/Claims/Schemes/CNST Conflict of interest statement None declared. Funding sources None.
1. Office of National Statistics. Birth statistics 2007. Series FMI no. 36. London: ONS; 2008. 2. Gunby J, Bissonnette F, Librach C, Cowan L, on behalf of the IVF Directors Group of the Canadian Fertility and Andrology Society. Assisted reproductive technologies (ART) in Canada: 2006 results from the Canadian ART Register. Fertil Steril 2009;91:1721e30. 3. Choi Y, Bishai D, Minkovitz CS. Multiple births are a risk factor for postpartum maternal depressive symptoms. Pediatrics 2009;123:1147e54. 4. Confidential Enquiry into Maternal and Child Health. Perinatal mortality 2006: England, Wales and Northern Ireland. London: CEMACH; 2008. 5. RCOG Guideline No. 51. Management of monochorionic twin pregnancy. London: RCOG; 2009. 6. Dodd JM, Crowther CA. Specialised antenatal clinics for women with a multiple pregnancy for improving maternal and infant outcomes. Cochrane Database Syst Rev; 2007 (2):CD005300. 7. Vergani P, Ghidini A, Bozzo G, Sirtori M. Prenatal management of twin gestation. Experience with a new protocol. J Reprod Med 1991;36:667e71. 8. Luke B, Brown MB, Misiunas R, et al. Specialized prenatal care and maternal and infant outcomes in twin pregnancy. Am J Obstet Gynecol 2003;189: 934e8. 9. Norman JE, Mackenzie JE, Owen P, et al. Progesterone for the prevention of preterm birth in twin pregnancy (STOPPIT): a randomised, double-blind, placebo-controlled study and meta-analysis. Lancet 2009;373:2034e40. 10. Crowther CA. Hospitalisation and bed rest for multiple pregnancy. Cochrane Database Syst Rev; 2001 (1):CD000110. 11. Crowther CA. Caesarean delivery for the second twin. Cochrane Database Syst Rev; 1996 (1):CD000047. 12. Smith GC, Fleming KM, White IR. Birth order of twins and risk of perinatal death related to delivery in England, Northern Ireland, and Wales, 1994e2003: retrospective cohort study. BMJ 2007;334:576.
Contents lists available at ScienceDirect
Seminars in Fetal & Neonatal Medicine journal homepage: www.elsevier.com/locate/siny
Multiples clinic: a model for antenatal care Ellen Knox, William Martin* Birmingham Women’s Hospital, Metchley Park Road, Edgbaston B15 2TG, UK
s u m m a r y Keywords: Antenatal clinic Multiple pregnancy Twins
Antenatal care has become more focused in recent years with an increase in the number of specialist clinics providing care in a multidisciplinary manner. Multiple pregnancies are complex with complications for the mother and babies arising frequently. As a group they lend themselves well to a specialist clinic model where interested doctors and midwives can provide care tailored to the individual. This makes it less likely that complications will be missed and provides a consistent approach to care that patients desire. This article aims to describe models of care that can be given in such a clinic, acknowledging that one model will not fit all. The scant evidence that exists is presented along with selected examples of individual complications. Ó 2010 Elsevier Ltd. All rights reserved.
1. Introduction In recent years there has been a vogue for subspecialism and a multidisciplinary approach to antenatal care. This allows concentration of expertise in one place to provide the patient with optimal care. This care is provided (where relevant) by specialists other than obstetricians, an interested obstetrician supported by (specialist) midwives and with access to additional staff such as anaesthetists, sonographers, day assessment care, etc. There is a paucity of data to show that such specialist care provides improved outcomes but it is logical to assume that care provided by a team of doctors and midwives with an interest in a particular area is likely to be of better quality as it is impossible to be knowledgeable about all aspects of obstetric care. Twins pregnancies make up around 1% of pregnancies and the incidence appears to be increasing. In the UK in 1988, twins comprised 11.1 per 1000 maternities. In 2007 they represented 15.3 per 1000 maternities, with triplets and higher order multiples increasing almost three-fold.1 Dizygous pregnancy rates vary with maternal age, race, nutrition and geography with highest rates in Nigeria and the lowest in Japan. Monozygous twinning rates are fairly constant, at 3e5 per 1000 births, although there have been some anecdotal reports that the incidence is also increasing. These increases are largely due to assisted conception techniques, which result in multiple rates of up to 30%.2 Though predominantly dizygotic, pregnancies which result from assisted conception techniques are at greater risk of monozygotic division than those spontaneously conceived. Both the British Fertility Society and the * Corresponding author. Tel.: þ44 (0)121 6074708; fax: þ44 (0)121 6272667. . E-mail address: [email protected] (W. Martin). 1744-165X/$ e see front matter Ó 2010 Elsevier Ltd. All rights reserved. doi:10.1016/j.siny.2010.07.001
Human Fertilisation and Embryology Authority suggest transferring a maximum of two embryos in each treatment cycle, without compromising pregnancy success. Multiple pregnancies are high risk both for the mother and fetuses. From the maternal point of view there is an increased risk of most pregnancy complications, including miscarriage, hyperemesis gravidarum, premature labour and delivery, anaemia, pre-eclampsia, gestational diabetes, antepartum and postpartum haemorrhage, polyhydramnios, operative delivery and increased stay in hospital, to name but a few. Women who have twins are also at increased risk of having problems with breastfeeding and developing postnatal depression.3 For the fetus and neonate, multiple pregnancies are associated with an increase in mortality compared with singleton pregnancies and this risk increases with increasing order of multiple pregnancy. Perinatal mortality rates are 27.2 and 81.8 per 1000 total births for twins, triplets and higher order multiple births respectively.4 The majority of perinatal deaths are associated with preterm birth and intrauterine growth restriction.4 Monochorionic (MC) twins have an increased loss rate (14.2%) compared with dichorionic (DC) twins (2.6%), mainly due to losses before 24 weeks. The differential loss rate is mainly the result of twinetwin transfusion syndrome (TTTS).5 Antenatal care focused in the correct way can help to ameliorate these risks by identifying the highest risk cases, and with appropriate monitoring and timing of delivery may help to improve outcomes. 2. Evidence for specialist clinics A literature review reveals that there has been little meaningful research carried out in the area of multiple pregnancy and antenatal specialist clinics. A 2009 Cochrane review concluded:
358
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There is no information available from randomised controlled trials to support the role of ‘specialised’ antenatal clinics for women with a multiple pregnancy compared with ‘standard’ antenatal care in improving maternal and infant health outcomes. The value of ‘specialised’ multiple pregnancy clinics in improving health outcomes for women and their infants requires evaluation in appropriately powered and designed randomised controlled trials.6 There are a few reports suggesting that management protocols may be of benefit.7,8 It seems plausible that dedicated antenatal clinics are beneficial. Women with twins and higher multiple pregnancy are at increased risk of complications. Thus frequent visits with staff tuned in to those risks are likely to lead to identification of such complications earlier. The Royal College of Obstetricians and Gynaecologists (RCOG) Green Top guidelines on monochorionic (MC) twin pregnancy suggest that care for these pregnancies may be best delivered in a dedicated clinic.5 Consistency of information including the use of specific multiple pregnancy guidelines and protocols is more likely. This will provide clarity for both staff and patients. Training is enhanced with the specialist clinic allowing more time for teaching of doctors, midwives and medical students. Centralisation of care aids in participation in multicentre trials and local audit, and allows development of databases to provide accurate unit data on outcome, further enhancing counselling for these complex pregnancies. Finally and perhaps of most importance, patients appreciate the specialist nature of the clinic. It tends not to be overcrowded and thus is less likely to be delayed, a frequent complaint about hospital antenatal clinics. Doctors and midwives have more time to spend discussing all aspects of antenatal and intrapartum care, thus they also prefer these clinics. All the patients attending are in the same boat, often making relationships that last until the birth of their twins and beyond. 3. General issues It is likely that a specialist antenatal multiple clinic will not be practical for all units. However, in a larger unit it is potentially more useful. At the Birmingham Women’s Hospital we deliver more than 7000 babies per annum; this number includes around 140 twins and 3e6 higher multiples. This number lends itself well to a specific multiples clinic model. A specialist multiples clinic provides consistency in antenatal care provided by clinicians experienced in the management of multiple pregnancies. They should be familiar with the importance of monitoring, allowing delivery at the appropriate time in a given circumstance. The lead clinician should ideally be experienced in scanning to give a better appreciation of the subtleties of fetal growth assessment. In difficult cases such a clinician can assess problem pregnancies themselves if there is any cause for concern. 4. Antenatal clinic models Traditionally management of multiple pregnancy is within an antenatal clinic setting. It relies upon scans being performed in the radiology department followed by review in the antenatal clinic. If there are complications then referral is made to a fetal medicine centre. However, an alternative model would be for uncomplicated DC twin pregnancies to be reviewed within a general antenatal clinic and the MC or complicated DC pregnancies being scanned and managed by the multiples lead and specialist midwife sonographers/ radiographers. This could be done through the day assessment unit. This would allow for greater ‘hands on’ input for the more complicated pregnancies. However, the uncomplicated twin pregnancies would not experience the (admittedly unproven) potential benefits
of attending a multiples clinic. The guidance for their care and for referral back to the multiples service if required would also have to be consistently implemented through protocols and/or care pathways. 5. Clinic visit schedule The first point of contact will be at the first visit. The diagnosis may already be known to the couple or potentially have been discovered moments before. A considerable amount of information will be imparted at this visit; much of it will not be retained, and therefore written information, preferably pertaining to the booking hospital figures and outcomes, should be provided when available. Issues requiring discussion include: Any relevant pre-existing conditions that are identified during routine questioning from the booking history. Frequency of attendance: in our clinic MC twins every 2 weeks from diagnosis to identify TTTS early; for DC twins attendance is every 4 weeks from 20 weeks. Risks of the pregnancy to include general advice about hyperemesis gravidarum, anaemia, pregnancy-induced hypertension and its detection, fetal growth problems and how they may be managed with increased frequency of visits and through care in a day assessment unit where possible; and the preterm labour risk. Prenatal diagnosis of Down’s syndrome screening. At Birmingham Women’s Hospital we offer nuchal translucency screening for all patients booking with multiple pregnancy, as it is a more reliable method than the triple test. It is important that the couple are adequately counselled regarding the implications of a disparity in results between the fetuses. They need to be aware of the risks of invasive testing and the possibility of fetal reduction in the event of an anomaly being identified. Ideally this should be discussed a few days prior to the test to allow the couple a chance to consider their position. (The National Screening Committee have produced a patient advice booklet pertaining to these issues e see below.) It is equally important, particularly when a couple have declined trisomy 21 screening to discuss the 20 week scan, to ensure the couple is aware that this is a screening test also. In MC pregnancies, the couple needs to be advised that there is a risk of TTTS of around 15%, and that this can best be identified by frequent scanning throughout pregnancy. (It is helpful to couch this in more positive terms, i.e. that there is an 85% chance that TTTS will not occur). The timings of subsequent clinic visits are determined largely by chorionicity with DC twin pregnancies requiring scanning every 4 weeks from 20 weeks of gestation. If there is any suggestion of suboptimal growth or growth discordance, growth scans should be performed every two weeks, with additional assessment occurring more frequently, for example where there is reduced liquor or abnormal umbilical artery Doppler. If Doppler velocimetry of the umbilical artery is normal, the liquor volume is normal and movements are subjectively satisfactory, then outpatient management in the setting of a day assessment unit or similar can be considered. Abnormal Doppler findings will necessitate more intensive surveillance. These issues are discussed in detail elsewhere in this issue of Seminars. Monochorionic twins require scanning every 2 weeks from diagnosis to delivery,5 to allow the earliest possible diagnosis of TTTS, which if untreated has high mortality for both twins. In MC twins not complicated by TTTS the presence of severe growth discordance may lead to compromise and demise of one twin which carries a risk of severe morbidity and mortality for the surviving twin. Growth discordance is best managed under the
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supervision of the multiples lead, through a fetal assessment/day assessment unit with appropriate fetal medicine review if required. Suspected development of TTTS should trigger referral to a tertiary referral fetal medicine unit with the capability to provide laser treatment if the diagnosis is confirmed.5 6. Delivery Timing of delivery and mode of delivery should be discussed early, and reviewed regularly throughout the pregnancy. At Birmingham Women’s Hospital we prefer to deliver by 38 weeks in uncomplicated MC twins and DC twins where the first twin is cephalic and the couple wish to try. If couples are keen on caesarean section, the pros and cons are discussed including risks for subsequent pregnancies. If they still wish this mode of delivery then we arrange elective delivery between 37þ0 and 38þ0 weeks. The final decisions are made nearer to term to ensure that fetal lie is known and to allow the couple a chance to consider the options. 7. Conditions peculiar to multiple pregnancy A full discussion of such conditions is provided elsewhere in this issue, but some general issues are mentioned here for completeness. It is essential that good links and referral pathways to fetal medicine subspecialists are in place. Where there is discordancy in fetal abnormality, or chromosomal anomaly; where TTTS develops or is suspected; or in higher order pregnancies where selective reduction may be considered, it is important to be able to refer promptly for further counselling and treatment. It is ideal if the lead for multiple pregnancy is subspecialty-trained in fetal medicine and can carry out some or all of the procedures that may be required. This means that they will be able to counsel appropriately, providing the patient with a good understanding of the condition prior to the visit to the fetal medicine department. Single fetal demise is distressing at whatever point it happens in the pregnancy. This eventuality should be considered by the unit and protocols arranged so that in the event of such an occurrence, the sonographer is aware how to proceed. All units should have a quiet room away from antenatal clinic where the couple can be seated. If alone, there should be someone who can sit with the patient until a partner or friend can attend for support. The patient should be seen promptly by an experienced clinician to discuss the likely causes and how the pregnancy is likely to be managed from that point. Follow-up may be more appropriate in another clinic, but some couples wish to continue in the multiples clinic as an acknowledgement that they had previously been pregnant with twins. This desire should be respected, where possible, but in this circumstance the single demise must be clearly and carefully documented to avoid other staff making the understandable error of assuming the pregnancy is ongoing. It is equally important to warn the couple that if they continue in the specialist clinic that such an occurrence may happen. The couple should be offered the chance to see the bereavement team, who in turn should be made aware of the couple’s situation. If the fetal demise is after 24 weeks then at some point, but not on the day of diagnosis unless specifically asked, the couple must be made aware that the baby will require to be registered when born. The implications of demise in an MC twin pregnancy need to be broached and follow-up scans arranged, perhaps with magnetic resonance imaging some 6 weeks later to assess intracranial anatomy. Some more unusual complications require individualised care. For example, monoamniotic twins are likely to need ultrasound scans every 2 weeks from booking to delivery. In view of the risk of cord entanglement, delivery should be at 34 weeks, at the latest, by caesarean section (with prophylactic steroids at 32e33 weeks).
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Higher multiple pregnancies are uncommon. These require individual plans for management. For example, triplets involving a MC twin pair (triamniotic, DC) may develop TTTS. They should therefore have the same clinic/scan scheduling as MC twins. Triplets with separate placentas (triamniotic, trichorionic) are still at risk of growth discordance but not TTTS. In view of the former risk they would still require more frequent clinic attendance. 8. Scan charts for multiple pregnancies Although individual birth weight charts are available for use in singleton pregnancies, charts for twins are population-based. Validated birth weight centiles and estimated fetal weight charts customised for the physiological variables that affect birth weight are not available. Thus currently there is no alternative but to use scan-based biometry charts to assess abdominal circumference, femur length and head circumference to monitor fetal growth in multiple pregnancies. Asymmetrical growth (relatively small abdominal circumference in relation to head circumference and femur length) may suggest placental insufficiency. Symmetrical growth restriction is more likely to suggest either a constitutionally small fetus or an underlying chromosomal or viral cause (especially if the poor growth is of early onset). 9. Staff 9.1. Role of the specialist midwife The specialist midwife plays an important role in the multiples clinic. The need for regular scan review often means that women are seen infrequently by their own community midwife. The specialist midwife therefore provides invaluable midwifery support throughout their pregnancy. The social and financial pressures on patients who are pregnant with multiple pregnancies are often greater than those with a singleton. The midwife working with the lead obstetrician can help to highlight social concerns and refer on to the appropriate support agencies early in pregnancy to provide the necessary help that the woman and her family may need both antenatally and postnatally. They may also provide links to any local specific multiple birth support groups. Following medical consultation regarding the relative merits of vaginal birth versus caesarean section, the specialist midwife can provide additional support and the opportunity to discuss the process further which can help aid the decision-making process. They are also ideally suited to leading parentcraft lessons for this group of women and their partners. In this group the labour, delivery and subsequent postnatal period is often particularly daunting and requires specialist knowledgeable and reassuring support. The specialist midwife can have a role in the education of midwifery colleagues regarding all aspects of multiple pregnancy care, antenatal, intrapartum and postnatal. Although it will not be possible for one midwife to be present at the delivery of all twins, they can through education and support go a long way to ensuring that consistent care is provided to the patients. This applies not only to intrapartum care but also to the important postnatal period when women with twins require additional support with breastfeeding. 9.2. Role of the obstetrician The lead obstetrician is responsible for establishing guidelines for the antenatal and intrapartum management of multiple pregnancy. (S)he should determine a plan of care for each pregnancy at booking after careful review of previous medical and obstetric history and current pregnancy circumstances. (S)he should then be available to review that plan as the pregnancy progresses and
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provide advice to the junior medical staff assisting in clinic. The twins clinic provides an excellent opportunity for teaching because of a relatively small cohort of patients who present frequently, thereby offering continuity of care. It also provides exposure to many obstetric complications, most of which are found more frequently in multiple pregnancies, and the opportunity to learn from a senior clinician with a specific interest. As mentioned earlier, the lead obstetrician should have expertise in the antenatal and intrapatum management of multiple pregnancies. Ideally they should have training in fetal medicine, so that in the event of a complication arising they are able to scan themselves or be able to interpret scans carried out to ensure care is appropriate, prolonging the pregnancy to an optimal gestation and delivering at the correct juncture. If they do not have the practical scan skills themselves they should have a good understanding of the complications of fetal growth discordance in multiple pregnancy and rapid access to those who are able to scan and aid management and delivery decisions. 10. Governance The multiples clinic provides an ideal opportunity for the collection of data regarding pregnancy outcomes. The data obtained can be used in the counselling of patients, allowing them to make informed choices regarding their delivery options. For example, the risk of emergency caesarean after spontaneous or induced labour; or for the second twin following vaginal birth of the first twin. The data collected can be used in audit to help ensure that women are receiving the highest quality care. The importance of good quality care in multiple pregnancy has been recognised in the most recent Clinical Negligence Scheme for Trusts (CNST) National Health Service Litigation Authority (NHSLA) criteria. All trusts will need to have a multiple pregnancy guideline which includes, as a minimum, offering a dating scan and nuchal translucency screening for Down syndrome; a regimen for scan frequency and assessment; discussion regarding mode, timing and place of delivery; referral criteria for suspected TTTS and management of the second stage of labour. A new standard (3.4) for multiple pregnancies requires a case note review to ensure compliance with the guidelines. It is currently a pilot standard but is likely to be adopted as a full standard in the near future. The introduction of specialist clinics should improve care. This may be demonstrated through audit of outcome but the less measurable aspect of patient satisfaction can be assessed through surveys administered through the clinic to ensure care is optimal. It would be impossible (and for training purposes undesirable) for the multiple pregnancy lead to be present at all deliveries. However, through practical training (perhaps with scenario-based drills) they can help to familiarise staff with the practicalities of management in multiple pregnancies. 11. Research The presence of a dedicated multiples clinic provides an ideal opportunity to participate in research programmes. This may relate to conditions and outcomes specific to multiple pregnancy or more general obstetric research. In the realm of conditions specific to multiple pregnancy, one of the most frequently studied complications is prematurity, specifically interventions aiming to reduce premature delivery. The STOPPIT (Study for the prevention of preterm birth in twins) trial9 was a randomised controlled trial (RCT) of vaginal progesterone versus placebo, given to women with twin pregnancy with the aim of preventing preterm birth. There was no reduction in the rate of prematurity in the progesterone arm of the study. Therefore vaginal progesterone should not be given in twin pregnancy for preterm delivery prevention.
A Cochrane review of six studies addressing bed-rest for multiple pregnancy compared to outpatient monitoring concluded that bed rest did not reduce the risk of preterm birth or perinatal mortality.10 In fact significantly more women delivered preterm in the inpatient group of uncomplicated twin pregnancies. For triplet pregnancies there was a suggestion of benefit to inpatient care although the confidence limits around the effect size were large and could therefore have been due to chance variation. With regard to mode of delivery, a Cochrane review found insufficient evidence to support routine caesarean delivery for non-cephalic second twin.11 However, there is evidence that the second twin has higher risk of death and/or serious perinatal morbidity compared to the first twin if delivered vaginally but not if delivered by caesarean section.12 This question is being addressed by the Twin Births Study, an international RCT comparing vaginal delivery with caesarean section for twins at 32e38 weeks (with an estimated weight of 1500e4000 g) where the first twin is presenting vertex and the second twin is nonvertex. Monoamniotic twin pregnancies, lethal congenital malformations of either twin or contraindications to vaginal birth are exclusions to entry in the trial. We await the results of this study to help provide important information with which to counsel regarding mode of delivery. In lieu of such evidence, counselling regarding delivery should involve in-depth discussion about the possible risks and complications of either delivery mode, including risks to future pregnancies, and written information should be supplied. 12. Summary There is a paucity of meaningful research into the use of dedicated multiple pregnancy clinics with a recent Cochrane review concluding that there was no information from RCTs supporting the role of such a clinic. However, it seems plausible that dedicated antenatal clinics are likely to be of benefit providing consistency in care, and likely earlier identification of problems. The role of dedicated clinics is supported by the RCOG for MC twins at least, as a good practice point.5 Dedicated multiple pregnancy clinics have much to recommend them. They may not be helpful in all hospitals but centralisation of expertise when practical seems logical. Ongoing research is helping to guide management. Guidelines and protocols can ensure that consistent advice is given to patients. Complications are more likely to be identified sooner. Appropriate referral pathways should ensure that the various complications seen in multiple pregnancies are treated in the optimal way.
Clinical practice points Multiple pregnancy is well-suited to a specialist clinic model. The majority of multiple pregnancies are uncomplicated but counselling at the booking visit should discuss the commoner conditions that may occur. Screening for Down syndrome is best provided by first trimester nuchal translucency scanning. A scanning schedule should be 4-weekly from 24 weeks for DC twins and 2-weekly from diagnosis for MC twins. MC twins should be referred to tertiary fetal medicine centres where there is suspicion that TTTS is developing. Delivery should be by 38 weeks in DC twins, but there is controversy regarding MC twins with advice varying from elective caesarean section at 34 weeks to vaginal delivery at 38 weeks. Mode of delivery should be discussed and the patient’s wishes respected where safe. If elective caesarean section is contemplated there should be a full discussion including risks in subsequent pregnancy backed up by written information.
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References Research directions The lack of objective data showing that specialist clinics are beneficial suggests one avenue of research. Research in the optimal mode and gestation of delivery. Methods of prediction and prevention of preterm labour.
Appendix. Websites and relevant literature Twins and Multiple Births Association (TAMBA) http://www.tamba.org.uk/Page.aspx?pid¼195 (fee for joining) Multiple Birth Foundation (MBF) http://www.multiplebirths.org.uk/ (fee for obtaining literature produced) National Screening Committe, Down syndrome screening for multiple pregnancy, CNST standard 3.4: www.nhsla.com/Claims/Schemes/CNST Conflict of interest statement None declared. Funding sources None.
1. Office of National Statistics. Birth statistics 2007. Series FMI no. 36. London: ONS; 2008. 2. Gunby J, Bissonnette F, Librach C, Cowan L, on behalf of the IVF Directors Group of the Canadian Fertility and Andrology Society. Assisted reproductive technologies (ART) in Canada: 2006 results from the Canadian ART Register. Fertil Steril 2009;91:1721e30. 3. Choi Y, Bishai D, Minkovitz CS. Multiple births are a risk factor for postpartum maternal depressive symptoms. Pediatrics 2009;123:1147e54. 4. Confidential Enquiry into Maternal and Child Health. Perinatal mortality 2006: England, Wales and Northern Ireland. London: CEMACH; 2008. 5. RCOG Guideline No. 51. Management of monochorionic twin pregnancy. London: RCOG; 2009. 6. Dodd JM, Crowther CA. Specialised antenatal clinics for women with a multiple pregnancy for improving maternal and infant outcomes. Cochrane Database Syst Rev; 2007 (2):CD005300. 7. Vergani P, Ghidini A, Bozzo G, Sirtori M. Prenatal management of twin gestation. Experience with a new protocol. J Reprod Med 1991;36:667e71. 8. Luke B, Brown MB, Misiunas R, et al. Specialized prenatal care and maternal and infant outcomes in twin pregnancy. Am J Obstet Gynecol 2003;189: 934e8. 9. Norman JE, Mackenzie JE, Owen P, et al. Progesterone for the prevention of preterm birth in twin pregnancy (STOPPIT): a randomised, double-blind, placebo-controlled study and meta-analysis. Lancet 2009;373:2034e40. 10. Crowther CA. Hospitalisation and bed rest for multiple pregnancy. Cochrane Database Syst Rev; 2001 (1):CD000110. 11. Crowther CA. Caesarean delivery for the second twin. Cochrane Database Syst Rev; 1996 (1):CD000047. 12. Smith GC, Fleming KM, White IR. Birth order of twins and risk of perinatal death related to delivery in England, Northern Ireland, and Wales, 1994e2003: retrospective cohort study. BMJ 2007;334:576.