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Valsalva Ok during labor in women with congenital heart disease, study finds.

CHICAGO--The conventional teaching that pregnant women with congenital heart disease should undergo a passive second stage of labor assisted by forceps or vacuum delivery has been called into question.

Avoidance of active pushing during labor by such patients has long been recommended because of theoretical concerns that the reduction in preload and increased myocardial oxygen requirement that occur with the Valsalva maneuver place women with congenital heart disease at increased risk for cardiac events. But the issue has never actually been studied--until recently, noted Dr. Katherine E. Economy, a maternal-fetal medicine specialist at Brigham and Women's Hospital, Boston.

"We've looked at this in our institution, and what we found is that avoiding Valsalva is associated with worse maternal outcomes: more third-and fourth-degree lacerations and more postpartum hemorrhages. So although the patient numbers were small, this has really encouraged us to move away from doing assisted second stage," she said at the meeting.

Other dogmata widely accepted by cardiologists, obstetricians, and anesthesiologists are that pregnant women with congenital heart disease should routinely be delivered a few weeks early, and by cesarean section. Dr. Economy challenged both notions.

For the Valsalva study, she and her coinvestigators carried out a retrospective cohort study including 112 pregnancies in 65 women with congenital heart disease who were delivered at the hospital during 1998-2005. The focus was on evaluating obstetric outcomes, as the great majority of previous studies of pregnancy outcomes in patients with congenital heart disease addressed maternal cardiac events. Roughly three-quarters of the women were instructed not to push during the second stage of labor; they underwent a planned assisted delivery in accord with conventional teaching. However, during the study period a shift in practice philosophy occurred in the Boston congenital heart obstetric service, such that women were allowed a trial of pushing on an individualized basis.

Among the 62 pregnancies that reached the second stage of labor, nine (20%) postpartum hemorrhages and seven (16%) third-or fourth-degree lacerations occurred among 45 no-Valsalva patients, compared with none in 17 (0%) women who pushed during labor. The only maternal adverse cardiac event (2%) occurred in a woman who did not do the Valsalva maneuver. Adverse obstetric events occurred in one-third of women. However, a multivariate analysis didn't identify any reliable independent predictors for sustaining an adverse obstetric event. Thus, women with congenital heart disease who move forward with pregnancy are at an overall increased risk for adverse obstetric outcomes, but baseline maternal cardiac factors aren't helpful in picking out a higher-risk subgroup.

The most common adverse obstetric outcome was preterm delivery; the 21% incidence was nearly twice that seen in the general population. Also noteworthy were the 14% incidence of postpartum hemorrhage and the 10% rate of preterm premature rupture of membranes (Int. J. Cardiol. 2010;144:195-9).

Dr. Economy observed that with growing numbers of women with congenital heart disease who survive well into their childbearing years, congenital heart disease now accounts for more than 50% of heart disease in pregnancy. And although maternal deaths due to hemorrhage or venous thromboembolism have fallen sharply over the last 20 years, maternal deaths from cardiovascular disease have risen. Indeed, cardiac disease in pregnancy is now the leading cause of indirect maternal mortality.

She noted that in discussing the possibility of termination in the event of unplanned pregnancy in a patient with congenital heart disease, it's important to understand that by the second trimester, many of the cardiovascular changes in pregnancy--including a 30%-50% increase in cardiac output, a drop in systemic vascular resistance, and an increase in heart rate--will already have occurred. At that point, the maternal risk may not be altered all that much by terminating.

Managing maternal cardiac risk in patients with congenital aortic root dilatation in accord with joint multi-specialty society-backed guidelines (J. Am. Coll. Cardiol. 2010;55:1509-44) entails strict blood pressure control with a beta-blocker, the discontinuation of angiotensin receptor blocker therapy, a monthly or bimonthly echocardiography, an MRI without gadolinium, and delivery in a center with cardiac surgery backup.

In the management of obstetric risk in patients with aortic disease, Dr. Economy recommends a first-trimester ultrasound for dating, sequential cervical length measurements beginning at 16 weeks, serious consideration of cerclage placement if the cervix shortens, and ultrasound for fetal growth surveillance.

Timing of delivery is individualized based upon cardiac status, gestational age, Bishop score, and other factors.

"Many of you probably start to lose your nerve a bit at the end and say, 'Pregnancy is bad for heart disease; we should just deliver.' But generally speaking, if your patients are doing well in the third trimester, there's really no reason to induce prematurity" Dr. Economy asserted.

She cited a large multicenter study that has turned heads in the world of maternal-fetal medicine. The study showed significantly increased rates of NICU admission, newborn sepsis, and respiratory complications requiring prolonged incubation with delivery at 37-38 weeks' gestation, compared with 39 weeks', in a broad population of pregnant women (N. Engl. J. Med. 2009;360:111-20).

"If your patients are doing well, let them stay pregnant," the ob.gyn. urged.

Cesarean section is really popular in patients with congenital heart disease. The joint guidelines state, "Fetal delivery via cesarean section is reasonable for patients with significant aortic enlargement, dissection, or severe aortic valve regurgitation" (Circulation 2010;121:1544-79). But Dr. Economy pointed out that this recommendation is rated class II, level of evidence C, meaning that it is based solely on expert opinion. And these joint guidelines were drawn up and approved by numerous cardiovascular and imaging societies without the endorsement of any obstetric organizations.

"I would put to you that every time you think about a cesarean section, you stop and remember that cesarean section is worse for women. For all women. C-section is worse for them, okay? It increases the risk of significant blood loss, increases infection risk, and increases the risk of venous thromboembolism," she said.

"My personal opinion is cesarean section should be reserved for obstetric indications--things like failure to progress, breech presentation, or nonreassuring fetal status in labor. The vast majority of patients will be better served by vaginal delivery. Plan on an interdisciplinary effort between obstetrics, cardiology, anesthesiology, and nursing," she advised.

Dr. Economy and her associates said they had no relevant financial disclosures.


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Author:Jancin, Bruce
Publication:OB GYN News
Date:Aug 1, 2012
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