Its been a while since I ranted about the CPS position statement regarding decision making around extremely preterm delivery. But I am currently in Europe where certain countries have specific thresholds for willingness to provide intensive interventions, thresholds which are somewhat more rigid than the guidelines of the CPS, which are often ignored. This made me think (dangerous I know) about what justification you could have for giving a specific threshold in completed weeks of gestational age below which stabilization and active intensive care for an extremely preterm baby would not be offered.
I think that for such an approach to be rational you would need 2 things, you would need to be able to know the gestational age with certainty, and you would also need to show that there was some substantial change in outcomes (survival or another outcome that you thought was important) at that precise moment. Then you could justify intervening at say 24 weeks and 0 days, but not at 23 weeks and 6 days. Or using the threshold of the CPS position statement, be sometimes willing to offer intervention at 23 weeks and 0 days, but never at 22 weeks 6 days.
We know that the second criterion is not satisfied, there is no step-wise change in outcomes at any particular date, and certainly not at the end of an arbitrary 7 day cyclical period known as a week. There is a gradual progressive change in survival with advancing gestational age, and major effects of birth weight, sex and other variables. In contrast there is little or no effect of gestational age on long term neurodevelopmental outcomes among survivors.
Which led me to think of the following story:
Suppose a mother pregnant with twins following IVF was in threatened labour. She has passed 22 weeks, and has been seen by the neonatologist. She wishes institution of intensive care, but is told by the neonatologist that it is not an option before 23 completed weeks; the consensus of the hospital where she is being looked after is that they should follow the CPS guidelines, and be prepared to intervene actively at 23 weeks, (but only after the mother has had the litany of possible negative outcomes related to her), whereas prior to 23 weeks, life-saving interventions are not offered.
Her contractions continue and the cervix dilates. Just before midnight on the day she reached 22 weeks and 6 days she delivers a little girl, who is placed in her arms for comfort care. 30 minutes later, just after midnight, the little boy delivers, and is intubated and taken to the NICU.
Would you actually do that? If you were to follow the CPS statement, the answer should be yes. Even if you are prepared to be flexible with twins, and treat them as a ‘package deal’ what about 2 mothers in adjoining rooms who deliver before and after midnight?
And what if the next day the mother comes to you and tells you that she had the Egg retrieval for her IVF at 2 pm in the afternoon. Oh no! The boy is actually only 22 weeks 6 days and 14 hours! We should not have intervened, maybe we should switch to comfort care…
You then find out that mother is referring to the original egg retrieval a couple of years ago, the obstetrician had known that and calculated the dates from the transfer of her embryos, which had been done at midnight because of a power failure during the day. Phew! So she really was exactly the gestation that they thought. we did the right thing after all.
The next day the obstetrician phones you sheepishly, to tell you that the mother actually had transfer of 5-day blastocysts not 3-day embryos. Which means that she had been actually 2 days further advanced in her pregnancy than they thought, so the little girl had actually been 23 weeks and 1 day gestation. So she should have been offered intensive care… Too late now.
This may seem absurd, but arbitrary limits to intensive interventions based on completed weeks of gestational age lead to such absurdities. When you add in the uncertainties of gestational age, the absurdities are multiplied.
This is a plea to recognize messiness. There are too many unknowns, and too many variables to have simplistic rules. Some of the variables can be quantified with precision, such as birth weight, some can be quantified but are imprecise (gestational age), and some can not be quantified at all, such as the values of the parents. We have to do the best we can, for the families we care for, making the best decisions possible in the uncertainties of real life.