Q&a attempts to provide balanced answers to those curly-yet-common questions in obstetrics and gynaecology for the broader O&G Magazine readership, including Diplomates, Trainees, medical students and other health professionals.
How would you manage the delivery of a healthy 39-year-old woman with a singleton pregnancy following seven years of infertility and IVF treatment?
Answer: Dr David Molloy (FRANZCOG)
The concept of unequal value for fetal outcome seems incongruous. We have long been taught and indeed preached, that all babies are equally precious and each deserves the same chance at optimum outcome. This is true in principle but not always practised. Parents, in particular, have different views as to how ‘precious’ their baby may be. Some smoke, drink, engage in other high-risk activity or expose their baby to higher risks of birth trauma or harm by delivery choice or mode, for example, homebirthing. Invariably, obstetricians categorise risk. unequal amounts of work may be put into the safe delivery of a low versus high-risk pregnancy. How then do you categorise a patient who may be having her only chance at a child? Is the fact that this pregnancy is likely to be a ‘one-off’ an additional factor which should alter your management beyond the usual risk parameters of age?
This particular case represents a hard won pregnancy with a low chance of replacing the baby if a disaster occurs. The Australian Institute of Health and Welfare (AIHW) data1 suggests a live birth rate for a repeat IVF cycle at 39 to 40 years of age of nine per cent for each repeat future cycle of treatment. Seven years of infertility is hardcore infertility with a low chance of natural conception and a reliance on reproductive technology to conceive.
It therefore makes sense to give this patient the best possible chance to take home a live healthy baby, the trade-off being more interventions hoping to shade the odds wherever possible towards least risk. In my delivery days, I would class these pregnancies as high premium as well as high-risk. Many of these mothers have no objections to additional intervention – their only goal is to take a healthy baby home in their arms. Interventions in the last 12 weeks of the pregnancy would include a double dose of betamethasone at 28 to 30 weeks and an ultrasound scan at 32 and 36 weeks for fetal assessment and intrauterine growth restriction. I would offer weekly visits from 32 or 34 weeks. These interventions lack an evidence base, like so much of obstetrics.
The key to risk reduction is to have a planned delivery by 39 weeks. Stillbirth risk increases exponentially from 37 to 41 weeks by a factor of 3 (1.3 to 4.6 /1000).2 There is no gain in exposing this baby to that risk after 38 weeks. If the patient was very eager, an induction and labour could be carried out under closely monitored circumstances if the cervix was very favourable, with quick resort to caesarean section as soon as any risk factor or aberration in the course of the labour arises, for example, any meconium, suboptimal CTG trace, failure to progress, etc.
Elective caesarean section with regional anaesthesia is an ideal mode of delivery for this patient. A 39-year-old primigravida is unlikely to have a favourable cervix at 38 to 39 weeks and this group often labours poorly. A caesarean section at 39 weeks offers a defined endpoint and lowest risk outcome for the baby, with a comparable surgical risk for the mother to that of a vaginal delivery in a primiparous patient. In my recent obstetric days, my caesarean section rate was over 90 per cent for IVF pregnancies aged 38 years or older and all were delivered by 39 weeks. No disasters, thank goodness. Caesar rules!
Answer: Dr Sue Jacobs (FRANZCOG)
Optimal management of this woman’s delivery begins at the first antenatal visit, at which time a thorough history needs to be taken in order to assess her level of risk in addition to her age of 39, infertility and IVF, each of which is associated with complications of pregnancy and delivery. Establishing a good rapport at the outset is essential as it will be important that she feels confident with the advice given during pregnancy and delivery. She will receive much information about her risks and will need reassurance that with careful antenatal care and appropriate management the risks can be minimised.
Singleton IVF pregnancies are at higher risk of preterm birth and low birth weight babies compared to spontaneously conceived singleton pregnancies.1 Subfertility/infertility per se appears to have an adverse impact on pregnancy outcomes, independent of ART/IVF.2 Maternal age over 35 is associated with lower birth weight (OR 1.8) and higher rates of preterm delivery (OR 1.7), when controlling for smoking, parity, multiple gestation and maternal medical disease.3 Stillbirth rates increase progressively with maternal age over 35 and the risk is magnified after 38 weeks gestation, sharply increasing after 40 weeks gestation.4 However, it must be remembered that the absolute risk of stillbirth in developed countries is low. Compared with women under 35, a woman aged 39 is more likely to be affected by hypertension (preexisting and/or pregnancy-related), diabetes (pregestational or gestational) and higher BMI. Dysfunctional labour increases in a linear fashion with advancing maternal age.5
This woman’s pregnancy should be managed with extra vigilance due to her high risk factors. As described she has no underlying health problems and normal pre-pregnancy BMI. Antenatal screening tests, including 75 g glucose tolerance tests at 16 to 18 weeks and 28 to 30 weeks, were normal. She has no other obstetric complications.
Fetal growth should be monitored carefully, both clinically at each visit, and sonograghically at 32 to 34 weeks gestation, with subsequent serial scans if indicated. I would advocate vaginal birth if presentation is cephalic and fetal growth is satisfactory. The advantages and disadvantages of vaginal birth versus elective caesarean section in her particular case should be discussed in detail at 36 weeks. Induction of labour (IOL) at 38 weeks should be advised if there is evidence of intrauterine growth restriction, oligohydramnios or any antepartum haemorrhage, even if small. If the woman does not have spontaneous onset of labour (SOL) by 39 to 40 weeks gestation, we would have further discussion about IOL. I would have a low threshold for IOL around 40 weeks, if no earlier indication. Continuous CTG monitoring in active labour is advisable due to high risk factors, preferably with telemetry to promote mobilisation. I would have a low threshold for caesarean section in labour. If it was decided to wait until 41 weeks gestation hoping for SOL, a formal ultrasound at 40 weeks should be considered and the importance of adequate fetal movements each day emphasised.
Management decisions regarding delivery should always be made together with the woman and her partner, with clear explanation of reasons for advice, listening carefully to each woman’s hopes and concerns.
Dr David Molloy’s answer:
- Wang, et al. Assisted reproductive technology in Australian and New Zealand 2007. Series No 13 Cat. No. PER47 page 11.
- Hankins GD, Clark SM, Munn MB. Caesarean section on request at 39 weeks: impact on shoulder dystocia, fetal trauma, neonatal encephalopathy and intrauterine fetal demise. Semin Perinatol. 2006 Oct; 30(5):276-87.
Dr Sue Jacobs’ answer:
- Schieve LA, Meikle SF, Ferre C, et al. Low and very low birth weight in infants conceived with use of assisted reproductive technology. N Engl J Med. 2002; 346:731.
- Romundstad LB, Romundstad PR, Sunde A, et al. Effects of technology or maternal factors on perinatal outcome after assisted fertilisation: a population-based cohort study. Lancet 2008; 372: 737.
- Tough SC, Newburn-Cook C, Johnston DW, et al. Delayed childbearing and its impact on population rate changes in lower birth weight, multiple birth, and preterm delivery. Paediatrics 2002; 109:399.
- Reddy uM, Ko CW, Willinger M. Maternal age and the risk of stillbirth throughout pregnancy in the united States. Am J Obstet Gynecol. 2006; 195:764.
- Greenberg MB, Cheng YW, Sullivan M, et al. Does length of labor vary by maternal age? Am J Obstet Gynecol. 2007; 197:428.