Cesarean Section Reduces Hepatitis C Transmission to Neonates from Infected Mothers

[Guest guest]

Cesarean Section Reduces Hepatitis C Transmission to Neonates from

Infected Mothers

29th September, 2000

Lancet 2000;356:904-907 - Abstract

New study findings suggest the transmission of the hepatitis C virus from

mother to child occurs most frequently at delivery.

Elective cesarean section was found to reduce transmission risk, and may be

an option to consider for pregnant women positive for the virus.

Writing in the September 9, 2000, issue of The Lancet, Dr. D.M. Gibb, of the

Medical Research Council Clinical Trials Unit in London, England, and

colleagues there and at two hospitals in Ireland pointed out that not much

is understood about vertical transmission of hepatitis C virus (HCV). As a

result, steps to reduce acquisition of the virus by newborns haven't been

determined ( " Mother-to-child transmission of hepatitis C virus: Evidence for

preventable peripartum transmission, " Lancet, September 9,

2000;356:904-907).

Gibb et al. undertook an investigation of mother-to-child transmission of

HCV, collecting data on 441 mothers and their children from the United

Kingdom and Ireland. They estimated vertical transmission rate and possible

risk factors that contribute to passing along the virus.

Due to questionable sensitivity of HCV RNA polymerase chain reaction (PCR)

and because of the timing of antibody tests, it was impossible to determine,

for most of the children, who had HCV infection and who did not. Therefore,

the probability of infection for each child was estimated based on the rate

of loss of antibody to HCV and the sensitivity and specificity of HCV RNA

PCR.

" Fifty percent of uninfected children became HCV-antibody negative by eight

months and 95% by 13 months, " the researchers reported.

" The estimated specificity of PCR for HCV RNA was 97% (95% confidence

interval, 96%-99%) and was unrelated to age; sensitivity was only 22% (95%

CI, 7%-46%) in the first month, but rose sharply to 97% (95% CI, 85%-100%)

thereafter, " Gibb and co-authors continued.

Using their probabilistic model, Gibb's team determined the overall rate of

vertical transmission in their study cohort to be 6.7%. They noted

particularly that, after adjusting for other factors, the transmission rate

was 3.8 times higher between HCV positive women coinfected with HIV and

their babies than between pairs in which the mother did not have HIV

(p=0.06).

Breastfeeding did not appear to be a risk factor for HCV transmission.

Elective cesarean section delivery prior to rupture of the uterine membrane

resulted in significantly lower risk of HCV transmission (p=0.04) than

vaginal delivery or emergency C-section, the researchers reported.

" The low sensitivity of HCV RNA soon after birth and the finding of a lower

transmission rate after delivery by elective cesarean section suggest that

HCV transmission occurs predominantly around the time of delivery, " wrote

Gibb and colleagues.

They feel that the low sensitivity of HCV RNA PCR renders testing of

newborns fairly useless in the first month of life. And, Gibb et al. said,

while a negative RNA PCR test after the first month almost definitely

indicates no HCV infection, a positive test doesn't guarantee infection and

so additional testing would be necessary for diagnosis.

The researchers also suggest that to avoid interference with maternal

antibodies, physicians should postpone HCV blood testing until children as

12 to 15 months old.

" If the findings on elective cesarean section are confirmed in other

studies, " they added, " the case for antenatal HCV testing should be

reconsidered. "

Key points included in this report are:

a.. Transmission of the hepatitis C virus from infected mother to child

appears to occur primarily at the time of delivery

b.. Detection of HCV RNA via polymerase chain reaction is not very

sensitive in the first month of life; researchers suggest waiting until the

child is 12 to 15 months of age

c.. Women coinfected with HCV and HIV had an almost four times greater

risk of transmitting HCV to their babies than women without HIV

d.. Women undergoing elective cesarean delivery had a lower risk of

transmitting HCV to their babies

[Guest guest]

Cesarean Section Reduces Hepatitis C Transmission to Neonates from

Infected Mothers

29th September, 2000

Lancet 2000;356:904-907 - Abstract

New study findings suggest the transmission of the hepatitis C virus from

mother to child occurs most frequently at delivery.

Elective cesarean section was found to reduce transmission risk, and may be

an option to consider for pregnant women positive for the virus.

Writing in the September 9, 2000, issue of The Lancet, Dr. D.M. Gibb, of the

Medical Research Council Clinical Trials Unit in London, England, and

colleagues there and at two hospitals in Ireland pointed out that not much

is understood about vertical transmission of hepatitis C virus (HCV). As a

result, steps to reduce acquisition of the virus by newborns haven't been

determined ( " Mother-to-child transmission of hepatitis C virus: Evidence for

preventable peripartum transmission, " Lancet, September 9,

2000;356:904-907).

Gibb et al. undertook an investigation of mother-to-child transmission of

HCV, collecting data on 441 mothers and their children from the United

Kingdom and Ireland. They estimated vertical transmission rate and possible

risk factors that contribute to passing along the virus.

Due to questionable sensitivity of HCV RNA polymerase chain reaction (PCR)

and because of the timing of antibody tests, it was impossible to determine,

for most of the children, who had HCV infection and who did not. Therefore,

the probability of infection for each child was estimated based on the rate

of loss of antibody to HCV and the sensitivity and specificity of HCV RNA

PCR.

" Fifty percent of uninfected children became HCV-antibody negative by eight

months and 95% by 13 months, " the researchers reported.

" The estimated specificity of PCR for HCV RNA was 97% (95% confidence

interval, 96%-99%) and was unrelated to age; sensitivity was only 22% (95%

CI, 7%-46%) in the first month, but rose sharply to 97% (95% CI, 85%-100%)

thereafter, " Gibb and co-authors continued.

Using their probabilistic model, Gibb's team determined the overall rate of

vertical transmission in their study cohort to be 6.7%. They noted

particularly that, after adjusting for other factors, the transmission rate

was 3.8 times higher between HCV positive women coinfected with HIV and

their babies than between pairs in which the mother did not have HIV

(p=0.06).

Breastfeeding did not appear to be a risk factor for HCV transmission.

Elective cesarean section delivery prior to rupture of the uterine membrane

resulted in significantly lower risk of HCV transmission (p=0.04) than

vaginal delivery or emergency C-section, the researchers reported.

" The low sensitivity of HCV RNA soon after birth and the finding of a lower

transmission rate after delivery by elective cesarean section suggest that

HCV transmission occurs predominantly around the time of delivery, " wrote

Gibb and colleagues.

They feel that the low sensitivity of HCV RNA PCR renders testing of

newborns fairly useless in the first month of life. And, Gibb et al. said,

while a negative RNA PCR test after the first month almost definitely

indicates no HCV infection, a positive test doesn't guarantee infection and

so additional testing would be necessary for diagnosis.

The researchers also suggest that to avoid interference with maternal

antibodies, physicians should postpone HCV blood testing until children as

12 to 15 months old.

" If the findings on elective cesarean section are confirmed in other

studies, " they added, " the case for antenatal HCV testing should be

reconsidered. "

Key points included in this report are:

a.. Transmission of the hepatitis C virus from infected mother to child

appears to occur primarily at the time of delivery

b.. Detection of HCV RNA via polymerase chain reaction is not very

sensitive in the first month of life; researchers suggest waiting until the

child is 12 to 15 months of age

c.. Women coinfected with HCV and HIV had an almost four times greater

risk of transmitting HCV to their babies than women without HIV

d.. Women undergoing elective cesarean delivery had a lower risk of

transmitting HCV to their babies