Delaying the delivery between the babies
Written by Assoc Prof Mark Umstad - AMBA Patron, Obstetrician, Gynaecologist
The risk of premature delivery in multiple pregnancies is high. Approximately 5% of twins and 12% of triplets will deliver before 28 weeks gestation.
Premature delivery exposes these babies to an increased risk of either not surviving or surviving with a significant handicap. In multiple births, all of the babies are delivered within a short period of time, typically under 30 minutes between delivery of the first and second twin during a vaginal delivery; this period is reduced to just one or two minutes between each one of the twins, triplets or quadruplets at caesarean section. In certain circumstances, the premature birth of one twin (or triplet or quadruplet) may not necessarily require the remaining babies to be delivered immediately.
In circumstances of extreme prematurity, there may be significant advantages in the remaining foetus (or foetuses) remaining in utero for an extended period of time. Almost always, a longer period in utero will be associated with an increase in chances of survival and a reduction in the chance of long-term disability. This deliberately long delay between delivery of the babies is referred to as delayed-interval delivery or interval delivery. Interval delivery is very rare. It is difficult to be certain of how frequently it is performed because not all cases are recorded and there is tendency to only report cases with successful outcomes. Where information is available for analysis, it is apparent that the rate of interval delivery in twin pregnancy is approximately 1 per 1000 sets of twins. Interval delivery should be considered when it is appropriate to deliver some but not all foetuses in a multiple birth pregnancy. This is typically in the presence of a condition such as cervical incompetence or premature labour when the underlying pathology will not place the remaining foetus or foetuses at risk.
Certain circumstances make interval delivery completely inappropriate. These include monochorionicity, placental abruption, intrauterine infection, severe pre-eclampsia (high blood pressure) or late gestation. The intention is to extend the pregnancy from pre-viability to adequate viability, so generally it will be considered prior to the 24 to 26 week gestation period and would not be appropriate at 28 to 30 weeks or beyond. Many techniques have been suggested for interval delivery. The technique described here applies to twins but is also applicable to triplets, quadruplets or more. The pre-viable foetus is delivered and then the cord of this baby is cut and tied. It is important at this stage that there are no further contractions nor active bleeding and that the remaining foetus is showing no signs of distress. This is a technique that requires adequate pain relief and the agreement and cooperation of the parent. Obstetricians have varying preferences as to whether antibiotics should be administered, whether a cervical suture should be placed or whether medication should be given to suppress contractions. As there are no robust studies proving the risk or benefit of any of these, this is very much an individual choice. After the procedure has been performed, very close and intensive monitoring is required for the remaining foetus to ensure that there are no signs of infection or distress. Hospitalisation is usually required for a considerable period after interval delivery.
There are a large number of case reports of interval delivery. The delay between the birth of the first and second twin can vary from several hours to over 20 weeks. Similar delays have been reported in triplet pregnancies. It is relatively common to have a 6-to10-week increase in the duration of pregnancy with delayed-interval delivery. The improvement in survival and reduction in long-term outcomes is directly related to the period of time for which the pregnancy is prolonged.
The most significant risk is that the procedure will be ineffective and the remaining foetus (or foetuses) will deliver in a short period of time and the benefit of prolonging the pregnancy is not seen. There is also a risk that the underlying pathology, which might be infection or haemorrhage, can worsen with the remaining foetuses in utero, and this can pose a significant risk to the mother’s health. Very careful observation and treatment of these conditions is essential and it is important that, if conditions deteriorate, then a decision be made to complete the delivery of all remaining foetuses. Given that the survival of any foetus born prior to 24 weeks gestation is very low and presents a very significant risk of long-term morbidity, and that survival at 28 weeks and beyond is in excess of 95%, with by far the majority of babies surviving without long-term disability, this critical period of time from prior to 24 weeks gestation to after 28 weeks gestation is of vital importance. Interval delivery offers an option that should be considered in exceptional circumstances but can prove to be highly effective.