Wednesday, January 02, 2008

C-section increases the risk of future hysterectomy

A study in the January 2008 issue of Obstetrics and Gynecology, Cesarean Delivery and Peripartum Hysterectomy, shows definitely that even one C-section increases the risk of a future peripartum (around the time of delivery) hysterectomy. This is not a new finding, but the paper is extremely well done and comprehensive. It also quantifies the risks in a variety of ways that will help women make informed decisions about C-section.

The study is a case-control study. They identified over 315 women who had a peripartum hysterectomy due to hemorrhage in a 13 month period. The controls were the 2 patients that had delivered in the same hospital, under the care of the same physician, immediately prior to the hysterectomy case. The reason for peripartum hysterectomy in 75% of the cases was placenta previa, placenta accreta, or uterine rupture.
Compared with controls, women who had had a peripartum hysterectomy were over three times more likely to have had a previous cesarean delivery. This risk increased with the number of previous cesarean deliveries, such that women with a peripartum hysterectomy were over eighteen times more likely to have had two or more previous cesarean deliveries. There was some evidence of an interaction between previous cesarean delivery and age; the risk associated with previous cesarean delivery was higher in women aged less than 35 years than in those aged 35 years or older...
Other risk factors for peripartum hysterectomy were also identified including: age greater than 35, parity greater than 3, previous uterine instrumentation, twin pregnancy, previous manual placenta removal and previous myomectomy. The authors calculated that approximately 28% of peripartum hysterectomies could be attributed to previous C-section.

Two women died after hysterectomy, for a case fatality rate of 0.6%.

Tha authors calculated the risk of needing a peripartum hysterectomy in different categories of women:
first delivery vaginally1:30,000
first delivery by C-section1:1700
delivery after one previous C-section1:1300
delivery after two or more previous C-sections1:220

Clearly, having a C-section in one pregnancy dramatically increases the risk of having a peripartum hysterectomy in a subsequent pregnancy. As the authors state:
We have also been able to identify that the risk also then extends beyond the initial cesarean delivery into subsequent deliveries; women who have had one previous cesarean delivery have more than double the risk of peripartum hysterectomy in the next pregnancy, and women who have had two or more previous cesarean deliveries have more than eighteen times the risk. This full quantification of these risks provides the evidence needed to comprehensively counsel women about the risks of primary cesarean delivery and to counsel against cesarean delivery without a specific medical indication.
Of course, in order to make an informed decision, women need to know the benefits, as well as the risks. Using the data from the paper, I did some additional calculations: Let us assume, as the authors claim, that for every 1300 women who have a C-section, one woman will ultimately require a peripartum hysterectomy. Let us make an extremely conservative assumption that of the 1300 primary C-sections, only 10% were required to save the life of the baby or mother or both. That would mean that 1300 C-sections would save at least 130 lives and probably more.

1300 primary C-sections130 lives saved1 current + 1 future peripartum hysterectomy

Most people would consider that the benefits of primary C-section would far outweigh the risks. So while the risks of future complications from C-section are real, and women should not have a C-section without a medical indication, the benefits are several orders of magnitude higher. As I have said many times in the past, it is difficult to imagine that most women would accept a substantial risk of neonatal death in an effort to avoid a very small risk of future complications.


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