epidemiology in 2000–2001, the reported overall incidence of gbs infection in newborn babies in the uk was 0.72 per 1,000 live births, 0.47 per 1,000 for gbs-eod and 0.25 per 1,000 for gbs-lod. very marked variations were observed, the incidence in scotland was 0.42 per 1,000, whilst in northern ireland, it was 0.9 per 1,000 live births. nevertheless, it may be a serious underestimation of the real incidence of gbs infections in newborns. a plausible explanation of this is that a considerable number of infants with probable gbs-eod had negative cultures as a result of a previous maternal antibiotic treatment that inhibits the growth of gbs in blood and cerebrospinal fluid cultures, but does not mask clinical symptoms. data collected prospectively for neonates that required a septic screen in the first 72 hrs of life in the uk, indicated a combined rate of definite and probable gbs-eod infection of 3.6 per 1,000 live births. another study on the epidemiology of invasive gbs infections in england and wales, reported a rise in the incidence of gbs-eod between 2000 and 2010 from 0.28 to 0.41 per 1,000 live births. rates of gbs-lod also increased between 1991 and 2010 from 0.11 to 0.29 per 1,000 live births in england and wales. in the past, the incidence of gbs-eod ranged from 0.7 to 3.7 per thousand live births in the us, and from 0.2 to 3.25 per thousand in europe. in 2008, after widespread use of antenatal screening and intrapartum antibiotic prophylaxis, the centers for disease control and prevention in the united states reported an incidence of 0.28 cases of gbs-eod per thousand live births in the us. from 2006 to 2015 the incidence of gbs eod decreased to 0.37 to 0.23 per thousand live births in the us. in contrast, the incidence of gbs-lod has remained unchanged at 0.26-0.31 per 1,000 live births in the us. falling incidence of gbs-eod in spain (castrillo group of hospitals) in spain, the incidence of gbs vertical sepsis declined by 73.6%, from 1.25/1,000 live births in 1996 to 0.33/1,000 in 2008. the "grupo de hospitales fundación castrillo" has also reported in 2018 an incidence of gbs eod of 0.17/1000 live births and 0,05/1000 gbs lod. in the barcelona area between 2004 and 2010, the incidence of gbs-eod was 0.29 per thousand living newborns, with no significant differences along the years. the mortality rate was 8.16%. in france since 2001, a rapid decrease in the incidence of the neonatal gbs infections has also been reported after widespread use of iap, from 0.7 to 0.2 per 1,000 births between 1997 and 2006. since 2012 the incidence of neonatal gbs infection has been estimated as 0.53 per 1,000 births in the european region, 0.67 in america, and 0.15 in australasia. countries reporting no use of iap had a 2.2-fold higher incidence of gbs-eod compared with those reporting any use of iap. estimates of the incidence of gbs eod per 1,000 births differs among countries, japan 0.09, panama 0,58, hong kong 0,76, and 2.35 in the dominican republic. overall, rates are highest in africa and lowest in asia. the estimate of the global incidence of gbs lod is 0.26 cases per 1,000 live births. it has been appraised that gbs infections cause at least 409.000 maternal/fetal/infant cases and 147.000 stillbirths and infant deaths worldwide annually. the following are estimates of the chances that a baby will be infected with a gbs neonatal infection if no preventive measures are taken and no other risk factors are present: one in 1,000 where the woman is not a known gbs carrier one in 400 where the woman carries gbs during the pregnancy one in 300 where the woman carries gbs at delivery one in 100 where the woman had a previous baby infected with gbs if a woman who carries gbs is given iap during labour, the baby's risk is reduced significantly: one in 8,000 where the mother carries gbs during pregnancy; one in 6,000 where the mother carries gbs at delivery; and one in 2,200 where the mother has previously had a baby infected with gbs royal college of obstetricians and gynaecologists (rcog) the royal college of obstetricians and gynaecologists (rcog) first issued their green top guideline no 36 "prevention of early onset neonatal group b streptococcal disease" in 2003. this guideline clearly stated: "routine bacteriological screening of all pregnant women for antenatal gbs carriage is not recommended, and vaginal swabs should not be taken during pregnancy unless there is a clinical indication to do so." but, "intrapartum antibiotic prophylaxis should be offered if gbs is detected on a vaginal swab in the current pregnancy." nevertheless, this guideline uses minimum incidence figures from a study undertaken in 2000–2001, so it could not only have underestimated the true incidence of gbs infection, but it could also have underestimated the risks to babies from gbs infection. gbs infection in babies has increased in england, wales, and northern ireland since 2003 (when the guideline was introduced). voluntarily reported cases from the communicable disease report/health protection agency show 0.48 cases per 1,000 live births in 2003, and this figure increased to 0.64 per 1,000 in 2009. in 2007, the rcog published the findings of their audit to evaluate practice in the uk obstetric units against their recommendations. the audit started out by comparing international guidelines for prevention of gbs-eod: highlighting the fact that, in contrast to the uk and new zealand guidelines, most of the other countries recommended identifying women for iap by offering effective tests to all pregnant women. the audit reviewed hospitals' protocols against gbs infection in newborns. of the 161 uk units, which submitted their protocol, four units did not even have a protocol for gbs, of those that did, 35% did not mention the 2003 rcog guideline, and only a minority of units had protocols entirely consistent with the guideline. further uk research published in 2010 looked at the opportunities for prevention of gbs-eod following the introduction of the rcog guideline. they found that, in the 48 cases of gbs during 2004 to 2007 (0.52/1,000 live births), only 19% of the mothers in whom risk factors were present were given adequate iap. the researchers stated: "if all women with risk factors received prophylaxis, 23 cases (48%) may have been prevented." the 2003 rcog guideline was reviewed in july 2012 and again in september 2017 with substantial changes. the second and final audit report into gbs (audit of current practice in preventing gbs eod in the uk) has been published. as a result of the audit, the rcog have recommended that the national guidelines for preventing gbs infection in newborns should be updated. in the uk, the rcog still does not recommend bacteriological screening of all pregnant women for antenatal gbs carriage in its 2017 guidelines, although it does state that women who tested positive in a previous pregnancy and the baby was well should be offered the option of testing and being offered intrapartum antimicrobial prophylaxis or having the iap without testing nevertheless, it is stated that if gbs carriage is detected incidentally or by intentional testing, women should be offered iap. and that all pregnant women should be provided with an appropriate information leaflet about gbs and pregnancy (published in december 2017). instead, women are treated according to their risk in labour. iap is offered to women in labout where gbs has been found from their urine or vaginal/rectal swabs taken during the pregnancy, and to women who have previously had a baby with gbs disease. immediate induction of labour and iap should be offered to all women with prelabour rupture of membranes at 37 weeks of gestation or more, to women whose membranes are ruptured more than 18 hours and to those who have fever in labour. women who are pyrexial in labour should be offered broad-spectrum antibiotics including an antibiotic appropriate for preventing eod-gbs. nice guidelines the uk's national institute for health and care excellence (nice) does not recommend routine testing for gbs, stating: "pregnant women should not be offered routine antenatal screening for group b streptococcus because evidence of its clinical and cost effectiveness remains uncertain." however, the guideline states that "at the first antenatal (booking) appointment (and later if appropriate), discuss and give information on .... infections that can impact on the baby in pregnancy or during birth (such as group b streptococcus, herpes simplex and cytomegalovirus)" nevertheless, the nice neonatal infection guideline states: "offer antibiotics during labour to women who: are in pre-term labour or have group b streptococcal colonisation, bacteriuria or infection during the current pregnancy or have had group b streptococcal colonisation, bacteriuria or infection in a previous pregnancy, and have not had a negative test for group b streptococcus by enrichment culture or pcr on a rectovaginal swab samples collected between 35 and 37 weeks' gestation or 3-5 weeks before the anticipated delivery date in the current pregnancy or have had a previous baby with an invasive group b streptococcal infection or have a clinical diagnosis of chorioamnionitis. ". national screening committee the uk national screening committee's current policy position on gbs is: "screening should not be offered to all pregnant women. this policy was reviewed in 2012, and despite receiving 212 responses, of which 93% advocated screening, the nsc has decided to not recommend antenatal screening. this decision was strongly criticized by the charity group b strep support as ignoring both the wishes of the public and the rising incidence rates of gbs infection in the uk. united states recommendations for iap to prevent perinatal gbs disease were issued in 1996 by the cdc. in these guidelines, the use of one of two prevention methods was recommended: either a risk-based approach or a culture-based screening approach. the cdc issued updated guidelines in 2002; these guidelines recommended the universal culture-based screening of all pregnant women at 35–37 weeks' gestation to optimize the identification of women who must receive iap. cdc also recommended that women with unknown gbs colonization status at the time of delivery be managed according to the presence of intrapartum risk factors. because of this strategy, the us has seen a major reduction in the incidence of gbs-eod. the cdc issued updated guidelines again in 2010, however, the foundations of prevention in the cdc's 2010 guidelines remained unchanged. the following were the main additions in the 2010 guidelines: expanded options for laboratory detection of gbs include the use of pigmented media and pcr assays. a revised colony count threshold was set for laboratories to report gbs in the urine of pregnant women. revised algorithms for gbs screening and use of iap for women with threatened preterm delivery include one algorithm for preterm labor and one for preterm premature rupture of membranes. recommendations for iap agents are presented in an algorithm format in an effort to promote the use of the most appropriate antibiotic for penicillin-allergic women. a minor change has been made to penicillin dosing to facilitate implementation in facilities with different packaged penicillin products. the neonatal management algorithm's scope was expanded to apply to all newborns. management recommendations depend upon clinical appearance of the neonate and other risk factors such as maternal chorioamnionitis, adequacy of iap if indicated for the mother, gestational age, and duration of membrane rupture. changes were made to the algorithm to reduce unnecessary evaluations in well-appearing newborns at relatively low risk for gbs-eod. in 2018, the task of revising and updating the gbs prophylaxis guidelines were transferred from the cdc to acog, to the american academy of pediatrics, aap and to the american society for microbiology, asm. the acog committee issued an updated document on prevention of group b streptococcal early-onset disease in newborns in 2019. acog's guidance replaced the 2010 guidelines published by cdc. this document does not introduce important changes from the cdc guidelines. the key measures necessary for preventing neonatal gbs early onset disease continue to be universal prenatal screening by culture of gbs from swabs collected from the lower vagina and rectum, correct collection and microbiological processing of the samples, and proper implementation of intrapartum antibiotic prophylaxis. it is also important to note that the acog recommended performing universal gbs screening between 36 and 37 weeks of gestation. this new recommendation provides a 5-week window for valid culture results that includes