The impact of multiple preterm births on the family
Correspondence: Dr E. Bryan, International Society for Twin Studies, Quercwm, Vowchurch, Hereford, HR2 ORL, UK.
Multiple births are important contributors to the preterm and low birthweight population and the numbers of twin births have been steadily rising since the early 1980s in all developed countries. This is largely due to the increased use of ovulation induction and multi-embryo transfer in the treatment of subfertility. Parents of preterm twins have been shown to be less responsive to their infants than those with singletons. Parental stress with twins has also been demonstrated by the higher incidence of maternal depression and of child abuse in multiple birth families. Furthermore, siblings of twins are more likely to have behaviour problems. Mortality and long-term morbidity rates are greatly increased amongst multiple birth children. The problems of the single surviving twin and the unaffected co-twin of a disabled child are often underestimated as is the complexity of the bereavement of parents who still have surviving multiples. Addressing the cause of the epidemic of iatrogenic multiple births is likely to be the single most effective way to reduce the number of preterm infants and the long-term problems to which they are prone.
Multiple births are increasingly large contributors to the preterm and low birthweight population. The average duration of pregnancy is 37 weeks for twins, 33.5 for triplets and 31.5 for quads. About 40% of twins and nearly all triplets and quads are born preterm (<37 weeks). Fifty percent of twins, 90% of triplets and nearly all quads have a birthweight of less than 2500 g. Half of the quadruplets weigh less than 1500 g compared to a quarter of triplets, 1 in 10 twins and 1 in a 100 singletons1.
Several studies have found that in-vitro fertilisation (IVF) twin infants have a still greater tendency to prematurity and low birthweight than those that are naturally conceived2.
Concerning twin births in general, the incidence has been steadily increasing in all developed countries, since the early 1980s3,4. In the UK, it has risen from 9.0 to 14.2 per 1000 births in 2000. The incidence of triplets has been rising much faster still and in the UK has quadrupled in the last 15 years5.
The increase in multiple births is largely due to the widespread use of poorly monitored ovulation induction and to multiple-embryo transfer in the treatment of subfertility. East Flanders in Belgium is the only region that has so far provided accurate population-based data on the origin of all multiple births6. In most countries, accurate data on conception are only available for those multiple births that arise following IVF or gamete donation. The most recent Annual Report of the UK's Human Fertilisation and Embryology Authority showed 27.3% of pregnancies following IVF were multiple births of which 3.3% were triplets. After micromanipulation and donor insemination, 26.9% and 6.4% were multiple births, respectively7.
Due to the complications of preterm delivery and low birthweight, the perinatal mortality and long-term morbidity rates are substantially increased compared with single born children, with IVF multiples being at greater risk than those spontaneously conceived7,8.
Population studies have shown a three to seven-fold higher incidence of cerebral palsy in twins compared to singletons and over 10-fold higher in triplets9. The highest rate of cerebral palsy being in surviving children whose co-twin or triplet died in utero9,10. The chances of any particular multiple pregnancy producing a bereaved family or a disabled child are of course much greater still9,11.
Couples who have tried for years to have a child could think they would be lucky to acquire two or even three at once—and hence an instant family. They could well picture two or three healthy, happy children. They would rarely picture the medical risks to the children or to the mother herself. Even less would such couples recognise the practical, financial and emotional stresses that are likely to result from having to cope with two or more children of the same age.
In this paper, I consider the impact of multiple births both on the children themselves and on their families. Others authors will explore their increasing impact on society in general.
Impacts on the Children
Although the development of most multiple birth children is within the normal range, these children, for both medical and environmental reasons, do face a higher risk of long-term disability, learning difficulties and language delay in particular12,13. Twin children have also been found to have less good concentration and a higher incidence of attention deficit hyperactivity disorder14.
The environment of a twin child (or triplet) differs in many ways from that of a single born. From the start, twins must share the maternal attention and communicate in a threesome. This can be difficult for both the children and the mother. Shortage of time and factors like safety will also tend to deprive them of many stimulating opportunities. Furthermore, multiples may never experience solitude and the self-sufficiency that can develop from it. The relationship between the twins themselves must also have an effect on each child's development, although little research has been done on this.
Having a chronically ill or disabled child will be hard for any parent. Where twins are involved, the emotional and practical upheavals are likely to be even greater. The twin child with a disability will find it difficult to understand why they and not their twin is affected. They will watch their co-twin doing things they may never be able to do and, if monozygotic (MZ), will have before them the constant image of how they might have been. Jealousy, anger and sometimes depression are not uncommon—and not surprising15.
It is not unusual for the sibling of a child with a disability to present with signs of psychological stress, as the disabled child receives so much more attention. Where the sibling is a twin there are likely to be extra difficulties. Jealousy in the early years followed later by guilt and an excessive burden of responsibility are common emotions of the unaffected twin. They may spend much time caring for their twin at the expense of their own activities and development.
Because most parents are proud of having twins they may find it hard to stop treating them the same, despite one having severe difficulties. This artificial imposition of ‘twinness’ can burden both children. Indeed the development of the more advanced child may be held back.
The Single Survivor
The child whose twin died in the perinatal period may suffer not only from the loss of his companion but also the grief of their parents. The parents may also come to idealise, even idolise, the dead twin. Some survivors have said their parents blamed them for the intrauterine death of their twin or would have preferred the other child to have survived especially if of the opposite sex16.
The surviving twin can have complex reactions to a twin's death17. Many feel angry with the twin for deserting them; for causing such unhappiness to the family; for making them feel guilty. They may be angry with their parents for ‘allowing’ the twin to die. Others feel guilty to have survived especially if at the expense of their twin as, for example, in the twin–twin transfusion syndrome.
When a twin child dies early in life, he/she is too often never mentioned. Teachers and even nursery staff may not hear at all of the twin and therefore misinterpret symptoms of unresolved grief or fail to note the bereaved child's need for comfort and explanation.
The Mother and Father
For many mothers, relating to one baby is a full-time occupation both emotionally and physically. The complexity of relating simultaneously to twins, in addition to the extra practical strains, can often cause great stress—which will be even greater if the babies are preterm or separated from her.
It is unfortunately not unusual for sick preterm multiples to have to be transferred from their hospital of delivery to tertiary care neonatal units1. Moreover, the mother may be unfit to travel with them. The babies themselves may be separated by many miles when no single tertiary unit can provide two or three intensive care cots at the time they are needed. This can become a logistic nightmare for the father as he tries to keep in touch with his partner and each baby and an emotional one for both parents.
It is common for mothers of twins to have a further emotional strain if one of the babies is notably more ill than the other. Mothers are more likely to be attracted to the healthier infant18. It is well established that mothers find it more difficult to relate to babies from whom they have been separated during their first days following delivery. Size, appearance and responsiveness may also influence the mother's first feelings about the babies.
One twin may be ready to go home before the other, but most units now try to discharge the babies together. Otherwise the baby left behind may suffer in their relationship with their mother. Moreover, it has been shown that early discharge from hospital is one of three factors significantly affecting the self-esteem of a school-age twin—the others being birth order and birthweight. Indeed earlier discharge from hospital is the most important19.
Every mother aims to give her babies the same amount of attention and to love them equally. She often feels guilty if she doesn't and cannot easily acknowledge that she actually prefers one to the other. Where one baby is more demanding, the mother may not only feel guilty that she is depriving the other twin of attention but resentful of having to spend so much time on a difficult baby at the expense of a positively responsive one.
The long-term effects of early mother–twin relationships have yet to be established. A recent study of preterm single-born and twins found that the mother of twins showed fewer initiatives and responses to their babies and were less responsive to both positive signals and to crying. They also lifted, held, touched and patted their babies less and talked less to them. When tested at 18 months, the cognitive development of the twins was less advanced than that of the single born controls and maternal behaviour in the newborn period was predictive of the level of development of the children at 18 months20. It is clearly vital that the children are followed to see if the effects of these early relationships persist into school.
Mothers of twins have been shown to suffer more from lack of sleep and fatigue than mothers of singleborns21. Furthermore, depression is more common well beyond the infancy period22. Isolation and fatigue are probably both contributory factors.
An increasing number of mothers of multiple births are relatively old4 and may find the pregnancy as well as the demands of caring for several young children especially stressful. Many of these will also be inexperienced first-time mothers.
Added stresses may derive from bereavement or having a child with special needs. The difficulties are increased by having to cope at the same time with children of the same age, but with very different needs15. Moreover, the parents, and often the child too, have a constant reminder in the unaffected child of how they both might—indeed should—have been. The special status of having or being a parent of twins is effectively lost if the twins look very different.
Parents who have lost a multiple but still have a surviving twin or one or two of triplets, face special problems17. They have a constant reminder of the dead child in the surviving child—especially if a MZ twin. Parents of multiple infants also lose what many of them see as a proud status and their bereavement is often underestimated by other people who may indeed tell them that they are fortunate to still have a surviving child. All these factors tend to inhibit a grieving process already delayed by natural preoccupation with the survivor.
The loss of babies from a higher multiple set can be particularly difficult23. After many years of infertility, a mother may suddenly have three, four or more live babies but then see one, two or more of them die soon after birth or die one by one over what can be many painful weeks or even months. Despite these deaths, a couple left with one or two babies often receive remarkably little sympathy about the death of the others. Some couples have to cope with their grief over the death of one (or more) babies while also having to face the daily difficulties and emotional strain of caring for a disabled child at the same time.
Higher Order Births
Detailed insights into the lives of families with triplets and higher order births first become available through the United Kingdom National Study of Triplets and Higher Order Births24. This population-based study of over 300 families with higher order birth British children born in 1980 and 1982–1985 covered medical and social aspects from the time of conception until the children were in school.
The report demonstrated that the practical difficulties of looking after three babies at once are huge, even when all are healthy. At the most simple level, no mother can carry three babies at once. Only with the greatest difficulty can she feed or transport them on her own. Many mothers cannot take their babies out of the home and so become housebound and isolated as a result.
The UK study repeatedly found that help for families, both statutory and private, had been inadequate in amount and slow to arrive. Too often the parents became ill and exhausted before help was provided. On other occasions, the discharge of the babies from the neonatal unit was unnecessarily delayed because extra help at home had not been arranged in time.
A mother simply cannot look after three babies on her own. There are not enough hours in the day. A study by the Australian Multiple Births Association showed that 197.5 hours per week were required to care for six-month-old triplets and to carry out the necessary household tasks25. Unfortunately a week only has 168 hours.
For a childless couple, the practical and emotional difficulties of caring for two or more babies at the same time may be particularly difficult to imagine. It has been shown that parents do not have realistic expectations of how the birth of twins will affect their life26. A preliminary study of couples who have twins following IVF indicated that they find parenting considerably less rewarding than they had expected27. The authors compared families with IVF twins and spontaneously conceived twins and found that for both mothers and fathers parenting stress was greater in the IVF group. The quality of parenting was equally good but parental satisfaction was less. This could well be due to the inevitable failure to reach the high standards of parenting they had for so long expected to achieve28.
A little recognised problem is the effect on other children in the family, particularly on the single toddler who has been the centre of the family, when he or she is suddenly displaced by an attention-attracting pair or trio. It has been shown that a sibling is likely to be more disturbed by the arrival of twins than of a single sibling and that behaviour problems in the older child are more common29.
As the number of higher multiple pregnancies has escalated, so have the number of couples who feel they should maximise the chances of having a healthy baby or twins by reducing the number of viable fetuses.
A recent international survey30 of 15 years experience of the procedure at 11 centres and a total of 3,513 cases showed that with increasing experience there has been a considerable improvement in the outcomes. There have been decreases in rates of pregnancy loss and of extreme prematurity and the reduction of quads as well as triplets down to twins now produce outcomes as good as those for unreduced twin gestations.
Nevertheless, multifetal pregnancy reduction (MFPR) is never an easy or uncontroversial solution and carries its own risk of medical and emotional complications23. Some parents will feel a lasting grief and guilt over the death of one or more potentially healthy children. Nevertheless it appears that the great majority of parents feel that they had made the right decision.
Support for Families Worldwide
Families will continue to need informed advice and support from those who care for them. The Multiple Births Foundation (MBF) was established in the UK in 1988 as the first organisation to offer professional support to families with twins, triplets and more as well as information, advice and training to the many medical, educational and social work staff concerned with their care. It has published five sets of Guidelines for the professional on the care of multiple birth families from before conception through to adolescence31.
Despite a limit in many countries of three embryos to be transferred in any one IVF cycle, the high and increasing incidence of multiple births in the most developed countries continues to cause concern. While as many as three embryos continue to be transferred, triplets will occur—and even quads. Monozygotic twinning is probably several times higher amongst pregnancies involving ovulation induction and embryo transfer32.
For many couples, a multiple pregnancy is too high a price to pay for their infertility treatment. An increasing number of European centres, particularly those in Scandinavia, are therefore now advocating single embryo transfers in selected women33.