What’s new in the other journals?
These snippets are extracts from a monthly service called the Journal Article Summary Service (JASS). JASS summarises clinically important O&G articles published the preceding month in the world literature. If you would like to receive details of how to subscribe, please email the editor Athol Kent at firstname.lastname@example.org or visit the website www.jassonline.com for more information.
For those at the cutting edge of computers and parturition, there is a gem of an article by Errol Norwitz from Yale (AJOG 2006;194:1510–2). It is about how computers can extract patterns from data fed into them and recognise sequences that are too complex to be picked up by standard computer programs or our brains. This artificial intelligence resembles human intelligence but can hold and connect more variables simultaneously than can our innate software.
The multifactorial initiation of labour may yield to such scrutiny, and the unravelling may have already begun. These sophisticated programs make in silico predictions—a term Norwitz uses to describe the complex solutions the computers come up with—as compared to in vitro or in vivo evidence. Presumably in silico will take its place in our new lexicon, so drop it into a ward round casually to impress your listeners.
For those in need to be conversant with the modern views of the onset of labour, this editorial is highly recommended.
The application of obstetric forceps is an art. Fears have been expressed that it may become a lost art as labour ward experience is reduced by shorter working hours or the willingness to apply them becomes discouraged by litigation threats (Nuthalapaty et al. AJOG 2006;194:1556–62). Indeed, the rise in caesarean section rates is, in part, attributed to obstetricians’ lack of skill or confidence in such assisted deliveries. The conundrum of less experience leading to less skill, plus fewer people willing to teach forceps deliveries, may be solved by technology.
Dupuis et al. from France (AJOG 2006;194:1524–31) have attached electrodes to specially designed forceps that can be used to deliver a dummy fetus from a plastic model. As the trainee applies the forceps blades, the three-dimensional trajectory of the blade moving around the dummy fetal head is projected onto a screen and plotted onto a graph. Direction and pressure are measured so the procedure can be safely learnt under controlled conditions until novices feel comfortable about putting on the forceps in an emergency situation. The article describes how senior doctors had clearly different techniques to junior doctors, eloquently demonstrating how experience in vivo does make a difference.
A good idea, but please don’t call it in plastico teaching.
Fifteen percentage of pregnancies end in miscarriage in the first trimester. The pregnancy fails and is either retained as an early fetal loss (previously called a missed abortion or a blighted ovum) or partially extruded giving rise to retained products of conception (previously called an incomplete abortion). The management of either can be expectant, medical or surgical, but the risks or advantages of each have not been tested head-to-head.
Now Trinder et al. (BMJ 2006;332:1235–8) report on a large randomised trial that clearly shows that all three options are acceptable treatments in terms of sepsis rates or haemorrhage. They allocated women to expectant, medical or surgical management and examined the outcomes 2 and 8 weeks later in terms of infection, bleeding, the need for evacuation and return to normal activities.
The expectant group were given no treatment but were told they could choose to have an evacuation. They were given routine follow-up appointments.
The medical group were treated with vaginal misoprostol in a somewhat outdated regimen in which women were assessed 8 hours after the initial administration and offered an evacuation. This is not consistent with modern methods, but the protocols for the trial were set 10 years ago, so better results with present day regimens could be anticipated. These days, success rates of more than 85% with misoprostol via oral and vaginal routes of administration are the norm.
The surgical group were given an evacuation on the next convenient operating list.
There were no prophylactic antibiotics used, and the sepsis rates in each arm of the study were 2–3%. Excessive bleeding was not a complication.
Weeks and Danielsson (BMJ 2006;332:1223–4) sum up the present situation as follows:
- • expectant management is safe with low risks of infection or dangerous blood loss and will probably allow most women to avoid admission to hospital
- • medical management will speed the process considerably and will make evacuation only necessary in 10–15% of women
- • surgical management will provide rapid resolution to her problem with low complication rates.
Antibiotic cover should only be used as a routine in circumstancies where sexually transmitted infections are prevalent. Women have a legitimate choice of resolution to a miscarriage, and the options are safe and should be offered.
In women, temperature control is mediated via the thermoregulatory centre in the brain.
The mechanism is a basic redistribution of blood depending in core temperatures. If the woman feels hot, then peripheral vasodilatation redirects blood flow to the skin where it cools, lowering core temperatures when it returns centrally. If cold, peripheral vasoconstriction plus shivering reduces surface blood cooling, conserving heat while the muscular activity of shivering generates warmth.
Oestrogen has a homeostatic effect on the thermoregulatory centre, so when oestrogen levels drop menopausally, the centre becomes labile and abnormal responses may be triggered by previously inconsequential temperature changes. The mechanism of action may be through adrenergic neurotransmission—which may explain why alpha-adrenergic agonists, like clonidine, can reduce flushing.
Another mechanism may be via serotonin neurotransmission—a theory supported by serotonin-reuptake-inhibitor efficacy in combating flushing. Whatever the final common pathway, most women experience hot flushes as their major symptom of oestrogen lack and are best treated by its replacement—a statement not in dispute. What is in dispute is the optimal duration of use for this indication and viable alternatives.
The Women’s Health Initiative (WHI) trial did nothing to answer this question but the meta-analysis of Nelson et al. (JAMA 2006;295:2057–71) examines nonhormonal therapies with some stringency. They identify selective serotonin-reuptake-inhibitors or their no-adrenaline counterparts, clonidine and gabapentin, as possibilities—but all are less effective than oestrogens. Complementary therapies are simply not considered useful at all.
The real problem is that the alternatives for menopausal flushes have not been monitored for any length of time. As Tica and Grady (JAMA 2006;295:2076–8) remind us, the WHI study shows that the absolute risk of combined hormonal replacement therapy is small, with less than one serious adverse effect per 1000 women per year, so other preparations have to prove better safety records to counter their lesser efficiency—a situation that does not exist at present.
Oestrogen remains the best treatment for immediate menopausal symptoms, with a clear risk/benefit profile, and the nonhormonal alternatives are ‘not optimal choices for most women’.
Chlorhexidine and pregnancy outcomes
Neonatal infection is a major source of morbidity and mortality, especially in the developing world. Of the four million neonatal deaths annually worldwide, the overwhelming majority occur in developing countries where resources to treat maternal infection are limited—and HIV is more prevalent. To prevent mother-to-child bacterial infection during delivery, various antibacterial agents can be used vaginally either as creams, gels or washes.
Goldenberg et al. (Obstet Gynecol 2006;107:1139–46) reviewed the literature of chlorhexidine as a suitable vaginal disinfectant and/or neonatal skin wash over the past 50 years and came up with some promising information. It is effective against a broad spectrum of bacteria implicated in perinatal infections such as group B streptococci, Klebsiella pneumoniae and Escherichia coli, it is nontoxic and nonirritating to mother, fetus or neonate. It is commercially available in the developing world as well as being cheap, costing less than one cent per application.
Chlorhexidine was originally developed as an antimalarial agent but was never used for that purpose. It is a highly cationic molecule that binds readily to negatively charged organic substrates and is slowly released over 24 hours or longer. It has a high safety profile with virtually no adverse effects, and reports of resistance are rare. There are wide concentrations used for vaginal examining lubricants in labour or as douches, ranging from 0.05 to 4%. There appears to be little systemic absorption, and no generalised adverse effects are known.
This review of all the trials published suggests that the greatest advantages of chlorhexidine use would be in situations with the highest sepsis rates, and unsurprisingly, these are the places where randomised trials are least likely to be carried out. Studies from Egypt and Malawi yielded positive results, so maybe it is pragmatic to use it in such circumstances until new data confirm, or refute, its promising potential.
Clotting and flying
Much debate has arisen around a link between flying and thrombosis. Long-haul flights do expose us to prolonged periods of relative hypoxia at low pressure, combined with inactivity, but does the combination make thrombosis more likely—even if we have no risk factors?
It seems not. Toff et al. (JAMA 2006;295:2251–61) simulated an 8-hour flight by placing volunteers in an oxygen chamber set to commercial aircraft flying conditions, then at ground settings and checked their clotting factors. Changing the environment to hyperbaric and hypoxia flight levels makes little difference to laboratory-testable thrombosis propensity.
If you are a Factor V Leiden positive or using oral contraceptives, then take extra precautions, otherwise keep well hydrated (not with alcohol), flex and extend your ankle and knee joints and walk around the cabin as often as you can.
Are mobile phones dangerous?
There are one billion mobile phones worldwide. Even if they pose the slightest health risk, this could be important, so experts have been looking into the potential risk of cerebral gliomas in frequent users. Although there is no biological mechanism for radiofrequency radiation to cause cancer—this worst-case scenario has been investigated.
Hepworth et al. (BMJ 2006;832:883–6) carried out a case–control study of UK citizens who had developed gliomas and matched them with controls to see if the index cases were more frequent mobile phone users. They were not, and even if there were a cause and effect association, this would take decades to become apparent. It would seem mobile phones do not ‘fry our brains’.
But mobile phones are dangerous—extremely. They increase the number of road accidents if used while driving by about 25%. This applies to hand-held and hands-free systems. Since the number of people killed in road-traffic accidents now tops 1 million, with 50 million injured per annum, any factor increasing these numbers should be avoided (Ameratunga et al. Lancet 2005;367:1533–40). They also predict that motor vehicle accidents will be the third greatest contributor to the world burden of disease in 15 years time.
Meanwhile, a letter in BMJ (Esprit et al. 2006;332:1513) records a girl struck by lightening while using her mobile phone in a London park during a storm. She was resuscitated but a year later has major disabilities from the strike. The authors quote three deaths under similar circumstances from newspapers in Asia and recommend the public should be made aware of this danger.