SMFM 27th Annual Meeting 2007
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This online presentation is made possible with an educational grant by Cytyc (formerly Adeza)
Hello, I’m Dr. Linda Pelaez. I’m currently a fourth year resident in Obstetrics and Gynecology at Weill Cornell Medical Centre. I’d like to talk about my poster presentation that was presented at the Society of Maternal Fetal Medicine conference in San Francisco, California.
The title of my study is Negative Fetal Fibronectin and Who Is Still Managed Aggressively and Whether it Helps. As we know, fetal fibronectin identified in the cervix vaginal secretions over the gestational age of 22 weeks has been correlated to the risk of preterm delivery. The negative predictive value has been shown to be, in multiple studies, up to 99 percent of delivery of seven days. Our main question was whether patients who have the negative fetal fibronectin test, and are symptomatic, whether they are contracting or dilated or have some cervical effacement, if these patients were being managed in a setting of a negative fetal fibronectin and whether the management of these patients actually made a difference.
What we did was we retrospectively reviewed patients’ charts who had been seen in our labor and delivery triage unit from December 2004 to July of 2006. We had 126 patients who had presented to labor and delivery with complaints of either pressure contractions, discharge and we identified these patients as sort of being ruled out preterm labor patients. We then proceeded to find 111 patients who had negative fetal fibronectin testing and we looked at these patients specifically. Interestingly, out of the 111 patients who had negative fetal fibronectin tests at the time of presentation and evaluation, 34 percent of these patients were managed aggressively. We defined aggressive treatment as admission to the hospital, tocolytic therapy, antibiotics or steroid use. We identified those patients as aggressive management. So those were 38 patients who were managed aggressively and 73 patients who were managed expectantly. The expected management group was usually just evaluated in triage, got a negative fetal fibronectin test, and were sent home.
At baseline our two groups of patients were similar with respect to the age of patient, the gestational age at testing, as well as whether they had had a prior preterm delivery, and parity. Interestingly, we discovered that the aggressive management patient was more dilated, more effaced and contracting more frequently. The dilation and contraction frequency was statistically significant and there was a trend in the effacement of over 40 percent of the cervix.
Our results showed that in both groups the gestational age of delivery was 38 weeks, whether you were treated or not in the face of a negative fetal fibronectin test. There was no difference in the gestational age at delivery, how many days after your fetal fibronectin test you delivered, delivery within seven days or delivery within 14 days. There was one patient in the expectant management group who delivered after 6 days of testing. Based on this we concluded that patients that were managed aggressively were those that were more symptomatic, contracting, dilated, but in the end in the face of a negative fetal fibronectin test, they did the same, and there was no improvement in outcome.
We then thought of the question as to whether these high-risk patients, because they were treated, if that was the reason that they delivered at 38 weeks and matched the group of the expectant management. We looked at that sub-analysis of patients, those that were either two cm dilated or contracting more than 12 contractions an hour, and in that sub-analysis the gestational age at delivery was again 38 weeks in both groups in the setting of a negative fetal fibronectin.
We concluded that even in the face of a negative fetal fibronectin test in the patient who we identified to be most symptomatic, most at risk for preterm delivery, the negative fetal fibronectin test still is very highly predictive of no delivery within 14 days, and there is no benefit in treating these patients aggressively.
If your patient is dilated and contracting with a negative fetal fibronectin test, we can conclude that treatment does not improve her outcome and treatment with tocolytics can be potentially dangerous to the patient as well.